/**
* In this file we will implement the automatic SLA support tree generation.
*
*/
#include <numeric>
#include "SLASupportTree.hpp"
#include "SLABoilerPlate.hpp"
#include "SLASpatIndex.hpp"
#include "SLABasePool.hpp"
#include <libslic3r/ClipperUtils.hpp>
#include <libslic3r/Model.hpp>
#include <boost/log/trivial.hpp>
#include <tbb/parallel_for.h>
/**
* Terminology:
*
* Support point:
* The point on the model surface that needs support.
*
* Pillar:
* A thick column that spans from a support point to the ground and has
* a thick cone shaped base where it touches the ground.
*
* Ground facing support point:
* A support point that can be directly connected with the ground with a pillar
* that does not collide or cut through the model.
*
* Non ground facing support point:
* A support point that cannot be directly connected with the ground (only with
* the model surface).
*
* Head:
* The pinhead that connects to the model surface with the sharp end end
* to a pillar or bridge stick with the dull end.
*
* Headless support point:
* A support point on the model surface for which there is not enough place for
* the head. It is either in a hole or there is some barrier that would collide
* with the head geometry. The headless support point can be ground facing and
* non ground facing as well.
*
* Bridge:
* A stick that connects two pillars or a head with a pillar.
*
* Junction:
* A small ball in the intersection of two or more sticks (pillar, bridge, ...)
*
* CompactBridge:
* A bridge that connects a headless support point with the model surface or a
* nearby pillar.
*/
namespace Slic3r {
namespace sla {
using Coordf = double;
using Portion = std::tuple<double, double>;
inline Portion make_portion(double a, double b) {
return std::make_tuple(a, b);
}
template<class Vec> double distance(const Vec& p) {
return std::sqrt(p.transpose() * p);
}
template<class Vec> double distance(const Vec& pp1, const Vec& pp2) {
auto p = pp2 - pp1;
return distance(p);
}
Contour3D sphere(double rho, Portion portion = make_portion(0.0, 2.0*PI),
double fa=(2*PI/360)) {
Contour3D ret;
// prohibit close to zero radius
if(rho <= 1e-6 && rho >= -1e-6) return ret;
auto& vertices = ret.points;
auto& facets = ret.indices;
// Algorithm:
// Add points one-by-one to the sphere grid and form facets using relative
// coordinates. Sphere is composed effectively of a mesh of stacked circles.
// adjust via rounding to get an even multiple for any provided angle.
double angle = (2*PI / floor(2*PI / fa));
// Ring to be scaled to generate the steps of the sphere
std::vector<double> ring;
for (double i = 0; i < 2*PI; i+=angle) ring.emplace_back(i);
const auto sbegin = size_t(2*std::get<0>(portion)/angle);
const auto send = size_t(2*std::get<1>(portion)/angle);
const size_t steps = ring.size();
const double increment = 1.0 / double(steps);
// special case: first ring connects to 0,0,0
// insert and form facets.
if(sbegin == 0)
vertices.emplace_back(Vec3d(0.0, 0.0, -rho + increment*sbegin*2.0*rho));
auto id = coord_t(vertices.size());
for (size_t i = 0; i < ring.size(); i++) {
// Fixed scaling
const double z = -rho + increment*rho*2.0 * (sbegin + 1.0);
// radius of the circle for this step.
const double r = std::sqrt(std::abs(rho*rho - z*z));
Vec2d b = Eigen::Rotation2Dd(ring[i]) * Eigen::Vector2d(0, r);
vertices.emplace_back(Vec3d(b(0), b(1), z));
if(sbegin == 0)
facets.emplace_back((i == 0) ? Vec3crd(coord_t(ring.size()), 0, 1) :
Vec3crd(id - 1, 0, id));
++ id;
}
// General case: insert and form facets for each step,
// joining it to the ring below it.
for (size_t s = sbegin + 2; s < send - 1; s++) {
const double z = -rho + increment*double(s*2.0*rho);
const double r = std::sqrt(std::abs(rho*rho - z*z));
for (size_t i = 0; i < ring.size(); i++) {
Vec2d b = Eigen::Rotation2Dd(ring[i]) * Eigen::Vector2d(0, r);
vertices.emplace_back(Vec3d(b(0), b(1), z));
auto id_ringsize = coord_t(id - int(ring.size()));
if (i == 0) {
// wrap around
facets.emplace_back(Vec3crd(id - 1, id,
id + coord_t(ring.size() - 1)));
facets.emplace_back(Vec3crd(id - 1, id_ringsize, id));
} else {
facets.emplace_back(Vec3crd(id_ringsize - 1, id_ringsize, id));
facets.emplace_back(Vec3crd(id - 1, id_ringsize - 1, id));
}
id++;
}
}
// special case: last ring connects to 0,0,rho*2.0
// only form facets.
if(send >= size_t(2*PI / angle)) {
vertices.emplace_back(Vec3d(0.0, 0.0, -rho + increment*send*2.0*rho));
for (size_t i = 0; i < ring.size(); i++) {
auto id_ringsize = coord_t(id - int(ring.size()));
if (i == 0) {
// third vertex is on the other side of the ring.
facets.emplace_back(Vec3crd(id - 1, id_ringsize, id));
} else {
auto ci = coord_t(id_ringsize + coord_t(i));
facets.emplace_back(Vec3crd(ci - 1, ci, id));
}
}
}
id++;
return ret;
}
// Down facing cylinder in Z direction with arguments:
// r: radius
// h: Height
// ssteps: how many edges will create the base circle
// sp: starting point
Contour3D cylinder(double r, double h, size_t ssteps, const Vec3d sp = {0,0,0})
{
Contour3D ret;
auto steps = int(ssteps);
auto& points = ret.points;
auto& indices = ret.indices;
points.reserve(2*ssteps);
double a = 2*PI/steps;
Vec3d jp = sp;
Vec3d endp = {sp(X), sp(Y), sp(Z) + h};
// Upper circle points
for(int i = 0; i < steps; ++i) {
double phi = i*a;
double ex = endp(X) + r*std::cos(phi);
double ey = endp(Y) + r*std::sin(phi);
points.emplace_back(ex, ey, endp(Z));
}
// Lower circle points
for(int i = 0; i < steps; ++i) {
double phi = i*a;
double x = jp(X) + r*std::cos(phi);
double y = jp(Y) + r*std::sin(phi);
points.emplace_back(x, y, jp(Z));
}
// Now create long triangles connecting upper and lower circles
indices.reserve(2*ssteps);
auto offs = steps;
for(int i = 0; i < steps - 1; ++i) {
indices.emplace_back(i, i + offs, offs + i + 1);
indices.emplace_back(i, offs + i + 1, i + 1);
}
// Last triangle connecting the first and last vertices
auto last = steps - 1;
indices.emplace_back(0, last, offs);
indices.emplace_back(last, offs + last, offs);
// According to the slicing algorithms, we need to aid them with generating
// a watertight body. So we create a triangle fan for the upper and lower
// ending of the cylinder to close the geometry.
points.emplace_back(jp); size_t ci = points.size() - 1;
for(int i = 0; i < steps - 1; ++i)
indices.emplace_back(i + offs + 1, i + offs, ci);
indices.emplace_back(offs, steps + offs - 1, ci);
points.emplace_back(endp); ci = points.size() - 1;
for(int i = 0; i < steps - 1; ++i)
indices.emplace_back(ci, i, i + 1);
indices.emplace_back(steps - 1, 0, ci);
return ret;
}
struct Head {
Contour3D mesh;
size_t steps = 45;
Vec3d dir = {0, 0, -1};
Vec3d tr = {0, 0, 0};
double r_back_mm = 1;
double r_pin_mm = 0.5;
double width_mm = 2;
double penetration_mm = 0.5;
// For identification purposes. This will be used as the index into the
// container holding the head structures. See SLASupportTree::Impl
long id = -1;
// If there is a pillar connecting to this head, then the id will be set.
long pillar_id = -1;
inline void invalidate() { id = -1; }
inline bool is_valid() const { return id >= 0; }
Head(double r_big_mm,
double r_small_mm,
double length_mm,
double penetration,
Vec3d direction = {0, 0, -1}, // direction (normal to the dull end )
Vec3d offset = {0, 0, 0}, // displacement
const size_t circlesteps = 45):
steps(circlesteps), dir(direction), tr(offset),
r_back_mm(r_big_mm), r_pin_mm(r_small_mm), width_mm(length_mm),
penetration_mm(penetration)
{
// We create two spheres which will be connected with a robe that fits
// both circles perfectly.
// Set up the model detail level
const double detail = 2*PI/steps;
// We don't generate whole circles. Instead, we generate only the
// portions which are visible (not covered by the robe) To know the
// exact portion of the bottom and top circles we need to use some
// rules of tangent circles from which we can derive (using simple
// triangles the following relations:
// The height of the whole mesh
const double h = r_big_mm + r_small_mm + width_mm;
double phi = PI/2 - std::acos( (r_big_mm - r_small_mm) / h );
// To generate a whole circle we would pass a portion of (0, Pi)
// To generate only a half horizontal circle we can pass (0, Pi/2)
// The calculated phi is an offset to the half circles needed to smooth
// the transition from the circle to the robe geometry
auto&& s1 = sphere(r_big_mm, make_portion(0, PI/2 + phi), detail);
auto&& s2 = sphere(r_small_mm, make_portion(PI/2 + phi, PI), detail);
for(auto& p : s2.points) z(p) += h;
mesh.merge(s1);
mesh.merge(s2);
for(size_t idx1 = s1.points.size() - steps, idx2 = s1.points.size();
idx1 < s1.points.size() - 1;
idx1++, idx2++)
{
coord_t i1s1 = coord_t(idx1), i1s2 = coord_t(idx2);
coord_t i2s1 = i1s1 + 1, i2s2 = i1s2 + 1;
mesh.indices.emplace_back(i1s1, i2s1, i2s2);
mesh.indices.emplace_back(i1s1, i2s2, i1s2);
}
auto i1s1 = coord_t(s1.points.size()) - coord_t(steps);
auto i2s1 = coord_t(s1.points.size()) - 1;
auto i1s2 = coord_t(s1.points.size());
auto i2s2 = coord_t(s1.points.size()) + coord_t(steps) - 1;
mesh.indices.emplace_back(i2s2, i2s1, i1s1);
mesh.indices.emplace_back(i1s2, i2s2, i1s1);
// To simplify further processing, we translate the mesh so that the
// last vertex of the pointing sphere (the pinpoint) will be at (0,0,0)
for(auto& p : mesh.points) z(p) -= (h + r_small_mm - penetration_mm);
}
void transform()
{
using Quaternion = Eigen::Quaternion<double>;
// We rotate the head to the specified direction The head's pointing
// side is facing upwards so this means that it would hold a support
// point with a normal pointing straight down. This is the reason of
// the -1 z coordinate
auto quatern = Quaternion::FromTwoVectors(Vec3d{0, 0, -1}, dir);
for(auto& p : mesh.points) p = quatern * p + tr;
}
double fullwidth() const {
return 2 * r_pin_mm + width_mm + 2*r_back_mm - penetration_mm;
}
Vec3d junction_point() const {
return tr + ( 2 * r_pin_mm + width_mm + r_back_mm - penetration_mm)*dir;
}
double request_pillar_radius(double radius) const {
const double rmax = r_back_mm;
return radius > 0 && radius < rmax ? radius : rmax;
}
};
struct Junction {
Contour3D mesh;
double r = 1;
size_t steps = 45;
Vec3d pos;
long id = -1;
Junction(const Vec3d& tr, double r_mm, size_t stepnum = 45):
r(r_mm), steps(stepnum), pos(tr)
{
mesh = sphere(r_mm, make_portion(0, PI), 2*PI/steps);
for(auto& p : mesh.points) p += tr;
}
};
struct Pillar {
Contour3D mesh;
Contour3D base;
double r = 1;
size_t steps = 0;
Vec3d endpoint;
long id = -1;
// If the pillar connects to a head, this is the id of that head
bool starts_from_head = true; // Could start from a junction as well
long start_junction_id = -1;
Pillar(const Vec3d& jp, const Vec3d& endp,
double radius = 1, size_t st = 45):
r(radius), steps(st), endpoint(endp), starts_from_head(false)
{
assert(steps > 0);
double h = jp(Z) - endp(Z);
assert(h > 0); // Endpoint is below the starting point
// We just create a bridge geometry with the pillar parameters and
// move the data.
Contour3D body = cylinder(radius, h, st, endp);
mesh.points.swap(body.points);
mesh.indices.swap(body.indices);
}
Pillar(const Junction& junc, const Vec3d& endp):
Pillar(junc.pos, endp, junc.r, junc.steps){}
Pillar(const Head& head, const Vec3d& endp, double radius = 1):
Pillar(head.junction_point(), endp, head.request_pillar_radius(radius),
head.steps)
{
}
void add_base(double height = 3, double radius = 2) {
if(height <= 0) return;
assert(steps >= 0);
auto last = int(steps - 1);
if(radius < r ) radius = r;
double a = 2*PI/steps;
double z = endpoint(2) + height;
for(size_t i = 0; i < steps; ++i) {
double phi = i*a;
double x = endpoint(0) + r*std::cos(phi);
double y = endpoint(1) + r*std::sin(phi);
base.points.emplace_back(x, y, z);
}
for(size_t i = 0; i < steps; ++i) {
double phi = i*a;
double x = endpoint(0) + radius*std::cos(phi);
double y = endpoint(1) + radius*std::sin(phi);
base.points.emplace_back(x, y, z - height);
}
auto ep = endpoint; ep(2) += height;
base.points.emplace_back(endpoint);
base.points.emplace_back(ep);
auto& indices = base.indices;
auto hcenter = int(base.points.size() - 1);
auto lcenter = int(base.points.size() - 2);
auto offs = int(steps);
for(int i = 0; i < last; ++i) {
indices.emplace_back(i, i + offs, offs + i + 1);
indices.emplace_back(i, offs + i + 1, i + 1);
indices.emplace_back(i, i + 1, hcenter);
indices.emplace_back(lcenter, offs + i + 1, offs + i);
}
indices.emplace_back(0, last, offs);
indices.emplace_back(last, offs + last, offs);
indices.emplace_back(hcenter, last, 0);
indices.emplace_back(offs, offs + last, lcenter);
}
bool has_base() const { return !base.points.empty(); }
};
// A Bridge between two pillars (with junction endpoints)
struct Bridge {
Contour3D mesh;
double r = 0.8;
long id = -1;
long start_jid = -1;
long end_jid = -1;
// We should reduce the radius a tiny bit to help the convex hull algorithm
Bridge(const Vec3d& j1, const Vec3d& j2,
double r_mm = 0.8, size_t steps = 45):
r(r_mm)
{
using Quaternion = Eigen::Quaternion<double>;
Vec3d dir = (j2 - j1).normalized();
double d = distance(j2, j1);
mesh = cylinder(r, d, steps);
auto quater = Quaternion::FromTwoVectors(Vec3d{0,0,1}, dir);
for(auto& p : mesh.points) p = quater * p + j1;
}
Bridge(const Junction& j1, const Junction& j2, double r_mm = 0.8):
Bridge(j1.pos, j2.pos, r_mm, j1.steps) {}
};
// A bridge that spans from model surface to model surface with small connecting
// edges on the endpoints. Used for headless support points.
struct CompactBridge {
Contour3D mesh;
long id = -1;
CompactBridge(const Vec3d& sp,
const Vec3d& ep,
const Vec3d& n,
double r,
size_t steps = 45)
{
Vec3d startp = sp + r * n;
Vec3d dir = (ep - startp).normalized();
Vec3d endp = ep - r * dir;
Bridge br(startp, endp, r, steps);
mesh.merge(br.mesh);
// now add the pins
double fa = 2*PI/steps;
auto upperball = sphere(r, Portion{PI / 2 - fa, PI}, fa);
for(auto& p : upperball.points) p += startp;
auto lowerball = sphere(r, Portion{0, PI/2 + 2*fa}, fa);
for(auto& p : lowerball.points) p += endp;
mesh.merge(upperball);
mesh.merge(lowerball);
}
};
// A wrapper struct around the base pool (pad)
struct Pad {
TriangleMesh tmesh;
PoolConfig cfg;
double zlevel = 0;
Pad() {}
Pad(const TriangleMesh& object_support_mesh,
const ExPolygons& baseplate,
double ground_level,
const PoolConfig& pcfg) :
cfg(pcfg),
zlevel(ground_level +
(sla::get_pad_fullheight(pcfg) - sla::get_pad_elevation(pcfg)) )
{
ExPolygons basep;
cfg.throw_on_cancel();
// The 0.1f is the layer height with which the mesh is sampled and then
// the layers are unified into one vector of polygons.
base_plate(object_support_mesh, basep,
float(cfg.min_wall_height_mm + cfg.min_wall_thickness_mm),
0.1f, pcfg.throw_on_cancel);
for(auto& bp : baseplate) basep.emplace_back(bp);
create_base_pool(basep, tmesh, cfg);
tmesh.translate(0, 0, float(zlevel));
}
bool empty() const { return tmesh.facets_count() == 0; }
};
// The minimum distance for two support points to remain valid.
static const double /*constexpr*/ D_SP = 0.1;
enum { // For indexing Eigen vectors as v(X), v(Y), v(Z) instead of numbers
X, Y, Z
};
PointSet to_point_set(const std::vector<Vec3d> &v)
{
PointSet ret(v.size(), 3);
{ long i = 0; for(const Vec3d& p : v) ret.row(i++) = p; }
return ret;
}
Vec3d model_coord(const ModelInstance& object, const Vec3f& mesh_coord) {
return object.transform_vector(mesh_coord.cast<double>());
}
inline double ray_mesh_intersect(const Vec3d& s,
const Vec3d& dir,
const EigenMesh3D& m)
{
return m.query_ray_hit(s, dir).distance();
}
// This function will test if a future pinhead would not collide with the model
// geometry. It does not take a 'Head' object because those are created after
// this test.
// Parameters:
// s: The touching point on the model surface.
// dir: This is the direction of the head from the pin to the back
// r_pin, r_back: the radiuses of the pin and the back sphere
// width: This is the full width from the pin center to the back center
// m: The object mesh
//
// Optional:
// samples: how many rays will be shot
// safety distance: This will be added to the radiuses to have a safety distance
// from the mesh.
double pinhead_mesh_intersect(const Vec3d& s,
const Vec3d& dir,
double r_pin,
double r_back,
double width,
const EigenMesh3D& m,
unsigned samples = 8,
double safety_distance = 0.001)
{
// method based on:
// https://math.stackexchange.com/questions/73237/parametric-equation-of-a-circle-in-3d-space
// We will shoot multiple rays from the head pinpoint in the direction of
// the pinhead robe (side) surface. The result will be the smallest hit
// distance.
// Move away slightly from the touching point to avoid raycasting on the
// inner surface of the mesh.
Vec3d v = dir; // Our direction (axis)
Vec3d c = s + width * dir;
const double& sd = safety_distance;
// Two vectors that will be perpendicular to each other and to the axis.
// Values for a(X) and a(Y) are now arbitrary, a(Z) is just a placeholder.
Vec3d a(0, 1, 0), b;
// The portions of the circle (the head-back circle) for which we will shoot
// rays.
std::vector<double> phis(samples);
for(size_t i = 0; i < phis.size(); ++i) phis[i] = i*2*PI/phis.size();
a(Z) = -(v(X)*a(X) + v(Y)*a(Y)) / v(Z);
b = a.cross(v);
// Now a and b vectors are perpendicular to v and to each other. Together
// they define the plane where we have to iterate with the given angles
// in the 'phis' vector
tbb::parallel_for(size_t(0), phis.size(),
[&phis, &m, sd, r_pin, r_back, s, a, b, c](size_t i)
{
double& phi = phis[i];
double sinphi = std::sin(phi);
double cosphi = std::cos(phi);
// Let's have a safety coefficient for the radiuses.
double rpscos = (sd + r_pin) * cosphi;
double rpssin = (sd + r_pin) * sinphi;
double rpbcos = (sd + r_back) * cosphi;
double rpbsin = (sd + r_back) * sinphi;
// Point on the circle on the pin sphere
Vec3d ps(s(X) + rpscos * a(X) + rpssin * b(X),
s(Y) + rpscos * a(Y) + rpssin * b(Y),
s(Z) + rpscos * a(Z) + rpssin * b(Z));
// Point ps is not on mesh but can be inside or outside as well. This
// would cause many problems with ray-casting. So we query the closest
// point on the mesh to this.
// auto psq = m.signed_distance(ps);
// This is the point on the circle on the back sphere
Vec3d p(c(X) + rpbcos * a(X) + rpbsin * b(X),
c(Y) + rpbcos * a(Y) + rpbsin * b(Y),
c(Z) + rpbcos * a(Z) + rpbsin * b(Z));
// Vec3d n = (p - psq.point_on_mesh()).normalized();
// phi = m.query_ray_hit(psq.point_on_mesh() + sd*n, n);
Vec3d n = (p - ps).normalized();
auto hr = m.query_ray_hit(ps + sd*n, n);
if(hr.is_inside()) { // the hit is inside the model
if(hr.distance() > 2*r_pin) phi = 0;
else {
// re-cast the ray from the outside of the object
auto hr2 = m.query_ray_hit(ps + (hr.distance() + 2*sd)*n, n);
phi = hr2.distance();
}
} else phi = hr.distance();
});
auto mit = std::min_element(phis.begin(), phis.end());
return *mit;
}
// Checking bridge (pillar and stick as well) intersection with the model. If
// the function is used for headless sticks, the ins_check parameter have to be
// true as the beginning of the stick might be inside the model geometry.
double bridge_mesh_intersect(const Vec3d& s,
const Vec3d& dir,
double r,
const EigenMesh3D& m,
bool ins_check = false,
unsigned samples = 4,
double safety_distance = 0.001)
{
// helper vector calculations
Vec3d a(0, 1, 0), b;
const double& sd = safety_distance;
a(Z) = -(dir(X)*a(X) + dir(Y)*a(Y)) / dir(Z);
b = a.cross(dir);
// circle portions
std::vector<double> phis(samples);
for(size_t i = 0; i < phis.size(); ++i) phis[i] = i*2*PI/phis.size();
tbb::parallel_for(size_t(0), phis.size(),
[&phis, &m, a, b, sd, dir, r, s, ins_check](size_t i)
{
double& phi = phis[i];
double sinphi = std::sin(phi);
double cosphi = std::cos(phi);
// Let's have a safety coefficient for the radiuses.
double rcos = (sd + r) * cosphi;
double rsin = (sd + r) * sinphi;
// Point on the circle on the pin sphere
Vec3d p (s(X) + rcos * a(X) + rsin * b(X),
s(Y) + rcos * a(Y) + rsin * b(Y),
s(Z) + rcos * a(Z) + rsin * b(Z));
auto hr = m.query_ray_hit(p + sd*dir, dir);
if(ins_check && hr.is_inside()) {
if(hr.distance() > 2*r) phi = 0;
else {
// re-cast the ray from the outside of the object
auto hr2 = m.query_ray_hit(p + (hr.distance() + 2*sd)*dir, dir);
phi = hr2.distance();
}
} else phi = hr.distance();
});
auto mit = std::min_element(phis.begin(), phis.end());
return *mit;
}
PointSet normals(const PointSet& points, const EigenMesh3D& mesh,
double eps = 0.05, // min distance from edges
std::function<void()> throw_on_cancel = [](){});
inline Vec2d to_vec2(const Vec3d& v3) {
return {v3(X), v3(Y)};
}
bool operator==(const SpatElement& e1, const SpatElement& e2) {
return e1.second == e2.second;
}
// Clustering a set of points by the given criteria
ClusteredPoints cluster(
const PointSet& points,
std::function<bool(const SpatElement&, const SpatElement&)> pred,
unsigned max_points = 0);
// This class will hold the support tree meshes with some additional bookkeeping
// as well. Various parts of the support geometry are stored separately and are
// merged when the caller queries the merged mesh. The merged result is cached
// for fast subsequent delivery of the merged mesh which can be quite complex.
// An object of this class will be used as the result type during the support
// generation algorithm. Parts will be added with the appropriate methods such
// as add_head or add_pillar which forwards the constructor arguments and fills
// the IDs of these substructures. The IDs are basically indices into the arrays
// of the appropriate type (heads, pillars, etc...). One can later query e.g. a
// pillar for a specific head...
//
// The support pad is considered an auxiliary geometry and is not part of the
// merged mesh. It can be retrieved using a dedicated method (pad())
class SLASupportTree::Impl {
std::vector<Head> m_heads;
std::vector<Pillar> m_pillars;
std::vector<Junction> m_junctions;
std::vector<Bridge> m_bridges;
std::vector<CompactBridge> m_compact_bridges;
Controller m_ctl;
Pad m_pad;
mutable TriangleMesh meshcache; mutable bool meshcache_valid = false;
mutable double model_height = 0; // the full height of the model
public:
double ground_level = 0;
Impl() = default;
inline Impl(const Controller& ctl): m_ctl(ctl) {}
const Controller& ctl() const { return m_ctl; }
template<class...Args> Head& add_head(Args&&... args) {
m_heads.emplace_back(std::forward<Args>(args)...);
m_heads.back().id = long(m_heads.size() - 1);
meshcache_valid = false;
return m_heads.back();
}
template<class...Args> Pillar& add_pillar(long headid, Args&&... args) {
assert(headid >= 0 && headid < m_heads.size());
Head& head = m_heads[size_t(headid)];
m_pillars.emplace_back(head, std::forward<Args>(args)...);
Pillar& pillar = m_pillars.back();
pillar.id = long(m_pillars.size() - 1);
head.pillar_id = pillar.id;
pillar.start_junction_id = head.id;
pillar.starts_from_head = true;
meshcache_valid = false;
return m_pillars.back();
}
const Head& pillar_head(long pillar_id) const {
assert(pillar_id >= 0 && pillar_id < m_pillars.size());
const Pillar& p = m_pillars[size_t(pillar_id)];
assert(p.starts_from_head && p.start_junction_id >= 0 &&
p.start_junction_id < m_heads.size() );
return m_heads[size_t(p.start_junction_id)];
}
const Pillar& head_pillar(long headid) const {
assert(headid >= 0 && headid < m_heads.size());
const Head& h = m_heads[size_t(headid)];
assert(h.pillar_id >= 0 && h.pillar_id < m_pillars.size());
return m_pillars[size_t(h.pillar_id)];
}
template<class...Args> const Junction& add_junction(Args&&... args) {
m_junctions.emplace_back(std::forward<Args>(args)...);
m_junctions.back().id = long(m_junctions.size() - 1);
meshcache_valid = false;
return m_junctions.back();
}
template<class...Args> const Bridge& add_bridge(Args&&... args) {
m_bridges.emplace_back(std::forward<Args>(args)...);
m_bridges.back().id = long(m_bridges.size() - 1);
meshcache_valid = false;
return m_bridges.back();
}
template<class...Args>
const CompactBridge& add_compact_bridge(Args&&...args) {
m_compact_bridges.emplace_back(std::forward<Args>(args)...);
m_compact_bridges.back().id = long(m_compact_bridges.size() - 1);
meshcache_valid = false;
return m_compact_bridges.back();
}
const std::vector<Head>& heads() const { return m_heads; }
Head& head(size_t idx) { meshcache_valid = false; return m_heads[idx]; }
const std::vector<Pillar>& pillars() const { return m_pillars; }
const std::vector<Bridge>& bridges() const { return m_bridges; }
const std::vector<Junction>& junctions() const { return m_junctions; }
const std::vector<CompactBridge>& compact_bridges() const {
return m_compact_bridges;
}
const Pad& create_pad(const TriangleMesh& object_supports,
const ExPolygons& baseplate,
const PoolConfig& cfg) {
m_pad = Pad(object_supports, baseplate, ground_level, cfg);
return m_pad;
}
void remove_pad() {
m_pad = Pad();
}
const Pad& pad() const { return m_pad; }
// WITHOUT THE PAD!!!
const TriangleMesh& merged_mesh() const {
if(meshcache_valid) return meshcache;
Contour3D merged;
for(auto& head : heads()) {
if(m_ctl.stopcondition()) break;
if(head.is_valid())
merged.merge(head.mesh);
}
for(auto& stick : pillars()) {
if(m_ctl.stopcondition()) break;
merged.merge(stick.mesh);
merged.merge(stick.base);
}
for(auto& j : junctions()) {
if(m_ctl.stopcondition()) break;
merged.merge(j.mesh);
}
for(auto& cb : compact_bridges()) {
if(m_ctl.stopcondition()) break;
merged.merge(cb.mesh);
}
for(auto& bs : bridges()) {
if(m_ctl.stopcondition()) break;
merged.merge(bs.mesh);
}
if(m_ctl.stopcondition()) {
// In case of failure we have to return an empty mesh
meshcache = TriangleMesh();
return meshcache;
}
meshcache = mesh(merged);
// TODO: Is this necessary?
//meshcache.repair();
BoundingBoxf3&& bb = meshcache.bounding_box();
model_height = bb.max(Z) - bb.min(Z);
meshcache_valid = true;
return meshcache;
}
// WITH THE PAD
double full_height() const {
if(merged_mesh().empty() && !pad().empty())
return get_pad_fullheight(pad().cfg);
double h = mesh_height();
if(!pad().empty()) h += sla::get_pad_elevation(pad().cfg);
return h;
}
// WITHOUT THE PAD!!!
double mesh_height() const {
if(!meshcache_valid) merged_mesh();
return model_height;
}
};
template<class DistFn>
long cluster_centroid(const ClusterEl& clust,
std::function<Vec3d(size_t)> pointfn,
DistFn df)
{
switch(clust.size()) {
case 0: /* empty cluster */ return -1;
case 1: /* only one element */ return 0;
case 2: /* if two elements, there is no center */ return 0;
default: ;
}
// The function works by calculating for each point the average distance
// from all the other points in the cluster. We create a selector bitmask of
// the same size as the cluster. The bitmask will have two true bits and
// false bits for the rest of items and we will loop through all the
// permutations of the bitmask (combinations of two points). Get the
// distance for the two points and add the distance to the averages.
// The point with the smallest average than wins.
std::vector<bool> sel(clust.size(), false); // create full zero bitmask
std::fill(sel.end() - 2, sel.end(), true); // insert the two ones
std::vector<double> avgs(clust.size(), 0.0); // store the average distances
do {
std::array<size_t, 2> idx;
for(size_t i = 0, j = 0; i < clust.size(); i++) if(sel[i]) idx[j++] = i;
double d = df(pointfn(clust[idx[0]]),
pointfn(clust[idx[1]]));
// add the distance to the sums for both associated points
for(auto i : idx) avgs[i] += d;
// now continue with the next permutation of the bitmask with two 1s
} while(std::next_permutation(sel.begin(), sel.end()));
// Divide by point size in the cluster to get the average (may be redundant)
for(auto& a : avgs) a /= clust.size();
// get the lowest average distance and return the index
auto minit = std::min_element(avgs.begin(), avgs.end());
return long(minit - avgs.begin());
}
/**
* This function will calculate the convex hull of the input point set and
* return the indices of those points belonging to the chull in the right
* (counter clockwise) order. The input is also the set of indices and a
* functor to get the actual point form the index.
*
* I've adapted this algorithm from here:
* https://www.geeksforgeeks.org/convex-hull-set-1-jarviss-algorithm-or-wrapping/
* and modified it so that it starts with the leftmost lower vertex. Also added
* support for floating point coordinates.
*
* This function is a modded version of the standard convex hull. If the points
* are all collinear with each other, it will return their indices in spatially
* subsequent order (the order they appear on the screen).
*/
ClusterEl pts_convex_hull(const ClusterEl& inpts,
std::function<Vec2d(unsigned)> pfn)
{
using Point = Vec2d;
using std::vector;
static const double ERR = 1e-3;
auto orientation = [](const Point& p, const Point& q, const Point& r)
{
double val = (q(Y) - p(Y)) * (r(X) - q(X)) -
(q(X) - p(X)) * (r(Y) - q(Y));
if (std::abs(val) < ERR) return 0; // collinear
return (val > ERR)? 1: 2; // clock or counterclockwise
};
size_t n = inpts.size();
if (n < 3) return inpts;
// Initialize Result
ClusterEl hull;
vector<Point> points; points.reserve(n);
for(auto i : inpts) {
points.emplace_back(pfn(i));
}
// Check if the triplet of points is collinear. The standard convex hull
// algorithms are not capable of handling such input properly.
bool collinear = true;
for(auto one = points.begin(), two = std::next(one), three = std::next(two);
three != points.end() && collinear;
++one, ++two, ++three)
{
// check if the points are collinear
if(orientation(*one, *two, *three) != 0) collinear = false;
}
// Find the leftmost (bottom) point
size_t l = 0;
for (size_t i = 1; i < n; i++) {
if(std::abs(points[i](X) - points[l](X)) < ERR) {
if(points[i](Y) < points[l](Y)) l = i;
}
else if (points[i](X) < points[l](X)) l = i;
}
if(collinear) {
// fill the output with the spatially ordered set of points.
// find the direction
hull = inpts;
auto& lp = points[l];
std::sort(hull.begin(), hull.end(),
[&lp, points](unsigned i1, unsigned i2) {
// compare the distance from the leftmost point
return distance(lp, points[i1]) < distance(lp, points[i2]);
});
return hull;
}
// TODO: this algorithm is O(m*n) and O(n^2) in the worst case so it needs
// to be replaced with a graham scan or something O(nlogn)
// Start from leftmost point, keep moving counterclockwise
// until reach the start point again. This loop runs O(h)
// times where h is number of points in result or output.
size_t p = l;
do
{
// Add current point to result
hull.push_back(inpts[p]);
// Search for a point 'q' such that orientation(p, x,
// q) is counterclockwise for all points 'x'. The idea
// is to keep track of last visited most counterclock-
// wise point in q. If any point 'i' is more counterclock-
// wise than q, then update q.
size_t q = (p + 1) % n;
for (size_t i = 0; i < n; i++)
{
// If i is more counterclockwise than current q, then
// update q
if (orientation(points[p], points[i], points[q]) == 2) q = i;
}
// Now q is the most counterclockwise with respect to p
// Set p as q for next iteration, so that q is added to
// result 'hull'
p = q;
} while (p != l); // While we don't come to first point
auto first = hull.front();
hull.emplace_back(first);
return hull;
}
Vec3d dirv(const Vec3d& startp, const Vec3d& endp) {
return (endp - startp).normalized();
}
/// Generation of the supports, entry point function. This is called from the
/// SLASupportTree constructor and throws an SLASupportsStoppedException if it
/// gets canceled by the ctl object's stopcondition functor.
bool SLASupportTree::generate(const PointSet &points,
const EigenMesh3D& mesh,
const SupportConfig &cfg,
const Controller &ctl)
{
// If there are no input points there is no point in doing anything
if(points.rows() == 0) return false;
PointSet filtered_points; // all valid support points
PointSet head_positions; // support points with pinhead
PointSet head_normals; // head normals
PointSet headless_positions; // headless support points
PointSet headless_normals; // headless support point normals
using IndexSet = std::vector<unsigned>;
// Distances from head positions to ground or mesh touch points
std::vector<double> head_heights;
// Indices of those who touch the ground
IndexSet ground_heads;
// Indices of those who don't touch the ground
IndexSet noground_heads;
// Groups of the 'ground_head' indices that belong into one cluster. These
// are candidates to be connected to one pillar.
ClusteredPoints ground_connectors;
// A help function to translate ground head index to the actual coordinates.
auto gnd_head_pt = [&ground_heads, &head_positions] (size_t idx) {
return Vec3d(head_positions.row(ground_heads[idx]));
};
// This algorithm uses the Impl class as its output stream. It will be
// filled gradually with support elements (heads, pillars, bridges, ...)
using Result = SLASupportTree::Impl;
Result& result = *m_impl;
// Let's define the individual steps of the processing. We can experiment
// later with the ordering and the dependencies between them.
enum Steps {
BEGIN,
FILTER,
PINHEADS,
CLASSIFY,
ROUTING_GROUND,
ROUTING_NONGROUND,
HEADLESS,
DONE,
HALT,
ABORT,
NUM_STEPS
//...
};
// t-hrow i-f c-ance-l-ed: It will be called many times so a shorthand will
// come in handy.
auto& tifcl = ctl.cancelfn;
// Filtering step: here we will discard inappropriate support points and
// decide the future of the appropriate ones. We will check if a pinhead
// is applicable and adjust its angle at each support point.
// We will also merge the support points that are just too close and can be
// considered as one.
auto filterfn = [tifcl] (
const SupportConfig& cfg,
const PointSet& points,
const EigenMesh3D& mesh,
PointSet& filt_pts,
PointSet& head_norm,
PointSet& head_pos,
PointSet& headless_pos,
PointSet& headless_norm)
{
// Get the points that are too close to each other and keep only the
// first one
auto aliases =
cluster(points,
[tifcl](const SpatElement& p, const SpatElement& se)
{
tifcl();
return distance(p.first, se.first) < D_SP;
}, 2);
filt_pts.resize(Eigen::Index(aliases.size()), 3);
int count = 0;
for(auto& a : aliases) {
// Here we keep only the front point of the cluster.
filt_pts.row(count++) = points.row(a.front());
}
tifcl();
// calculate the normals to the triangles belonging to filtered points
auto nmls = sla::normals(filt_pts, mesh, cfg.head_front_radius_mm, tifcl);
head_norm.resize(count, 3);
head_pos.resize(count, 3);
headless_pos.resize(count, 3);
headless_norm.resize(count, 3);
// Not all of the support points have to be a valid position for
// support creation. The angle may be inappropriate or there may
// not be enough space for the pinhead. Filtering is applied for
// these reasons.
int pcount = 0, hlcount = 0;
for(int i = 0; i < count; i++) {
tifcl();
auto n = nmls.row(i);
// for all normals we generate the spherical coordinates and
// saturate the polar angle to 45 degrees from the bottom then
// convert back to standard coordinates to get the new normal.
// Then we just create a quaternion from the two normals
// (Quaternion::FromTwoVectors) and apply the rotation to the
// arrow head.
double z = n(2);
double r = 1.0; // for normalized vector
double polar = std::acos(z / r);
double azimuth = std::atan2(n(1), n(0));
// skip if the tilt is not sane
if(polar >= PI - cfg.normal_cutoff_angle) {
// We saturate the polar angle to 3pi/4
polar = std::max(polar, 3*PI / 4);
// Reassemble the now corrected normal
Vec3d nn(std::cos(azimuth) * std::sin(polar),
std::sin(azimuth) * std::sin(polar),
std::cos(polar));
nn.normalize();
// save the head (pinpoint) position
Vec3d hp = filt_pts.row(i);
// the full width of the head
double w = cfg.head_width_mm +
cfg.head_back_radius_mm +
2*cfg.head_front_radius_mm;
// We should shoot a ray in the direction of the pinhead and
// see if there is enough space for it
double t = pinhead_mesh_intersect(
hp, // touching point
nn,
cfg.head_front_radius_mm, // approx the radius
cfg.head_back_radius_mm,
w,
mesh);
if(t > w || std::isinf(t)) {
head_pos.row(pcount) = hp;
// save the verified and corrected normal
head_norm.row(pcount) = nn;
++pcount;
} else if( polar >= 3*PI/4 ) {
// Headless supports do not tilt like the headed ones so
// the normal should point almost to the ground.
headless_norm.row(hlcount) = nn;
headless_pos.row(hlcount++) = hp;
}
}
}
head_pos.conservativeResize(pcount, Eigen::NoChange);
head_norm.conservativeResize(pcount, Eigen::NoChange);
headless_pos.conservativeResize(hlcount, Eigen::NoChange);
headless_norm.conservativeResize(hlcount, Eigen::NoChange);
};
// Pinhead creation: based on the filtering results, the Head objects will
// be constructed (together with their triangle meshes).
auto pinheadfn = [tifcl] (
const SupportConfig& cfg,
PointSet& head_pos,
PointSet& nmls,
Result& result
)
{
/* ******************************************************** */
/* Generating Pinheads */
/* ******************************************************** */
for (int i = 0; i < head_pos.rows(); ++i) {
tifcl();
result.add_head(
cfg.head_back_radius_mm,
cfg.head_front_radius_mm,
cfg.head_width_mm,
cfg.head_penetration_mm,
nmls.row(i), // dir
head_pos.row(i) // displacement
);
}
};
// Further classification of the support points with pinheads. If the
// ground is directly reachable through a vertical line parallel to the Z
// axis we consider a support point as pillar candidate. If touches the
// model geometry, it will be marked as non-ground facing and further steps
// will process it. Also, the pillars will be grouped into clusters that can
// be interconnected with bridges. Elements of these groups may or may not
// be interconnected. Here we only run the clustering algorithm.
auto classifyfn = [tifcl] (
const SupportConfig& cfg,
const EigenMesh3D& mesh,
PointSet& head_pos,
IndexSet& gndidx,
IndexSet& nogndidx,
std::vector<double>& gndheight,
ClusteredPoints& ground_clusters,
Result& result
) {
/* ******************************************************** */
/* Classification */
/* ******************************************************** */
// We should first get the heads that reach the ground directly
gndheight.reserve(size_t(head_pos.rows()));
gndidx.reserve(size_t(head_pos.rows()));
nogndidx.reserve(size_t(head_pos.rows()));
// First we search decide which heads reach the ground and can be full
// pillars and which shall be connected to the model surface (or search
// a suitable path around the surface that leads to the ground -- TODO)
for(unsigned i = 0; i < head_pos.rows(); i++) {
tifcl();
auto& head = result.head(i);
Vec3d dir(0, 0, -1);
bool accept = false;
int ri = 1;
double t = std::numeric_limits<double>::infinity();
double hw = head.width_mm;
// We will try to assign a pillar to all the pinheads. If a pillar
// would pierce the model surface, we will try to adjust slightly
// the head with so that the pillar can be deployed.
while(!accept && head.width_mm > 0) {
Vec3d startpoint = head.junction_point();
// Collision detection
t = bridge_mesh_intersect(startpoint, dir, head.r_back_mm, mesh);
// Precise distance measurement
double tprec = ray_mesh_intersect(startpoint, dir, mesh);
if(std::isinf(tprec) && !std::isinf(t)) {
// This is a damned case where the pillar melds into the
// model but its center ray can reach the ground. We can
// not route this to the ground nor to the model surface.
head.width_mm = hw + (ri % 2? -1 : 1) * ri * head.r_back_mm;
} else {
accept = true; t = tprec;
auto id = head.id;
// We need to regenerate the head geometry
head = Head(head.r_back_mm,
head.r_pin_mm,
head.width_mm,
head.penetration_mm,
head.dir,
head.tr);
head.id = id;
}
ri++;
}
// Save the distance from a surface in the Z axis downwards. It may
// be infinity but that is telling us that it touches the ground.
gndheight.emplace_back(t);
if(accept) {
if(std::isinf(t)) gndidx.emplace_back(i);
else nogndidx.emplace_back(i);
} else {
// This is a serious issue. There was no way to deploy a pillar
// for the given pinhead. The whole thing has to be discarded
// leaving the model potentially unprintable.
//
// TODO: In the future this has to be solved by searching for
// a path in 3D space from this support point to a suitable
// pillar position or an existing pillar.
// As a workaround we could mark this head as "sidehead only"
// let it go trough the nearby pillar search in the next step.
BOOST_LOG_TRIVIAL(warning) << "A support point at "
<< head.tr.transpose()
<< " had to be discarded as there is"
<< " nowhere to route it.";
head.invalidate();
}
}
// Transform the ground facing point indices top actual coordinates.
PointSet gnd(gndidx.size(), 3);
for(size_t i = 0; i < gndidx.size(); i++)
gnd.row(long(i)) = head_pos.row(gndidx[i]);
// We want to search for clusters of points that are far enough from
// each other in the XY plane to not cross their pillar bases
// These clusters of support points will join in one pillar, possibly in
// their centroid support point.
auto d_base = 2*cfg.base_radius_mm;
ground_clusters =
cluster(
gnd,
[d_base, tifcl](const SpatElement& p, const SpatElement& s)
{
tifcl();
return distance(Vec2d(p.first(X), p.first(Y)),
Vec2d(s.first(X), s.first(Y))) < d_base;
}, 3); // max 3 heads to connect to one centroid
};
// Helper function for interconnecting two pillars with zig-zag bridges.
// This is not an individual step.
auto interconnect = [&cfg](
const Pillar& pillar,
const Pillar& nextpillar,
const EigenMesh3D& emesh,
Result& result)
{
const Head& phead = result.pillar_head(pillar.id);
const Head& nextphead = result.pillar_head(nextpillar.id);
Vec3d sj = phead.junction_point();
sj(Z) = std::min(sj(Z), nextphead.junction_point()(Z));
Vec3d ej = nextpillar.endpoint;
double pillar_dist = distance(Vec2d{sj(X), sj(Y)},
Vec2d{ej(X), ej(Y)});
double zstep = pillar_dist * std::tan(-cfg.tilt);
ej(Z) = sj(Z) + zstep;
double chkd = bridge_mesh_intersect(sj, dirv(sj, ej), pillar.r, emesh);
double bridge_distance = pillar_dist / std::cos(-cfg.tilt);
// If the pillars are so close that they touch each other,
// there is no need to bridge them together.
if(pillar_dist > 2*cfg.head_back_radius_mm &&
bridge_distance < cfg.max_bridge_length_mm)
while(sj(Z) > pillar.endpoint(Z) + cfg.base_radius_mm &&
ej(Z) > nextpillar.endpoint(Z) + cfg.base_radius_mm)
{
if(chkd >= bridge_distance) {
result.add_bridge(sj, ej, pillar.r);
auto pcm = cfg.pillar_connection_mode;
// double bridging: (crosses)
if( pcm == PillarConnectionMode::cross ||
(pcm == PillarConnectionMode::dynamic &&
pillar_dist > 2*cfg.base_radius_mm))
{
// If the columns are close together, no need to
// double bridge them
Vec3d bsj(ej(X), ej(Y), sj(Z));
Vec3d bej(sj(X), sj(Y), ej(Z));
// need to check collision for the cross stick
double backchkd = bridge_mesh_intersect(bsj,
dirv(bsj, bej),
pillar.r,
emesh);
if(backchkd >= bridge_distance) {
result.add_bridge(bsj, bej, pillar.r);
}
}
}
sj.swap(ej);
ej(Z) = sj(Z) + zstep;
chkd = bridge_mesh_intersect(sj, dirv(sj, ej), pillar.r, emesh);
}
};
// Step: Routing the ground connected pinheads, and interconnecting them
// with additional (angled) bridges. Not all of these pinheads will be
// a full pillar (ground connected). Some will connect to a nearby pillar
// using a bridge. The max number of such side-heads for a central pillar
// is limited to avoid bad weight distribution.
auto routing_ground_fn = [gnd_head_pt, interconnect, tifcl](
const SupportConfig& cfg,
const ClusteredPoints& gnd_clusters,
const IndexSet& gndidx,
const EigenMesh3D& emesh,
Result& result)
{
const double hbr = cfg.head_back_radius_mm;
const double pradius = cfg.head_back_radius_mm;
const double maxbridgelen = cfg.max_bridge_length_mm;
const double gndlvl = result.ground_level;
ClusterEl cl_centroids;
cl_centroids.reserve(gnd_clusters.size());
SpatIndex pheadindex; // spatial index for the junctions
for(auto& cl : gnd_clusters) { tifcl();
// place all the centroid head positions into the index. We will
// query for alternative pillar positions. If a sidehead cannot
// connect to the cluster centroid, we have to search for another
// head with a full pillar. Also when there are two elements in the
// cluster, the centroid is arbitrary and the sidehead is allowed to
// connect to a nearby pillar to increase structural stability.
if(cl.empty()) continue;
// get the current cluster centroid
long lcid = cluster_centroid(cl, gnd_head_pt,
[tifcl](const Vec3d& p1, const Vec3d& p2)
{
tifcl();
return distance(Vec2d(p1(X), p1(Y)), Vec2d(p2(X), p2(Y)));
});
assert(lcid >= 0);
auto cid = unsigned(lcid);
cl_centroids.push_back(unsigned(cid));
unsigned hid = gndidx[cl[cid]]; // Head index
Head& h = result.head(hid);
h.transform();
Vec3d p = h.junction_point(); p(Z) = gndlvl;
pheadindex.insert(p, hid);
}
// now we will go through the clusters ones again and connect the
// sidepoints with the cluster centroid (which is a ground pillar)
// or a nearby pillar if the centroid is unreachable.
size_t ci = 0;
for(auto cl : gnd_clusters) { tifcl();
auto cidx = cl_centroids[ci];
cl_centroids[ci++] = cl[cidx];
size_t index_to_heads = gndidx[cl[cidx]];
auto& head = result.head(index_to_heads);
Vec3d startpoint = head.junction_point();
auto endpoint = startpoint; endpoint(Z) = gndlvl;
// Create the central pillar of the cluster with its base on the
// ground
result.add_pillar(long(index_to_heads), endpoint, pradius)
.add_base(cfg.base_height_mm, cfg.base_radius_mm);
// Process side point in current cluster
cl.erase(cl.begin() + cidx); // delete the centroid before looping
// TODO: dont consider the cluster centroid but calculate a central
// position where the pillar can be placed. this way the weight
// is distributed more effectively on the pillar.
auto search_nearest =
[&tifcl, &cfg, &result, &emesh, maxbridgelen, gndlvl, pradius]
(SpatIndex& spindex, const Vec3d& jsh)
{
long nearest_id = -1;
const double max_len = maxbridgelen / 2;
while(nearest_id < 0 && !spindex.empty()) { tifcl();
// loop until a suitable head is not found
// if there is a pillar closer than the cluster center
// (this may happen as the clustering is not perfect)
// than we will bridge to this closer pillar
Vec3d qp(jsh(X), jsh(Y), gndlvl);
auto ne = spindex.nearest(qp, 1).front();
const Head& nearhead = result.heads()[ne.second];
Vec3d jh = nearhead.junction_point();
Vec3d jp = jsh;
double dist2d = distance(qp, ne.first);
// Bridge endpoint on the main pillar
Vec3d jn(jh(X), jh(Y), jp(Z) + dist2d*std::tan(-cfg.tilt));
if(jn(Z) > jh(Z)) {
// If the sidepoint cannot connect to the pillar from
// its head junction, then just skip this pillar.
spindex.remove(ne);
continue;
}
double d = distance(jp, jn);
if(jn(Z) <= gndlvl + 2*cfg.head_width_mm || d > max_len)
break;
double chkd = bridge_mesh_intersect(jp, dirv(jp, jn),
pradius,
emesh);
if(chkd >= d) nearest_id = ne.second;
spindex.remove(ne);
}
return nearest_id;
};
for(auto c : cl) { tifcl();
auto& sidehead = result.head(gndidx[c]);
sidehead.transform();
Vec3d jsh = sidehead.junction_point();
SpatIndex spindex = pheadindex;
long nearest_id = search_nearest(spindex, jsh);
// at this point we either have our pillar index or we have
// to connect the sidehead to the ground
if(nearest_id < 0) {
// Could not find a pillar, create one
Vec3d jp = jsh; jp(Z) = gndlvl;
result.add_pillar(sidehead.id, jp, pradius).
add_base(cfg.base_height_mm, cfg.base_radius_mm);
// connects to ground, eligible for bridging
cl_centroids.emplace_back(c);
} else {
// Creating the bridge to the nearest pillar
const Head& nearhead = result.heads()[size_t(nearest_id)];
Vec3d jp = jsh;
Vec3d jh = nearhead.junction_point();
double d = distance(Vec2d{jp(X), jp(Y)},
Vec2d{jh(X), jh(Y)});
Vec3d jn(jh(X), jh(Y), jp(Z) + d*std::tan(-cfg.tilt));
if(jn(Z) > jh(Z)) {
double hdiff = jn(Z) - jh(Z);
jp(Z) -= hdiff;
jn(Z) -= hdiff;
// pillar without base, this does not connect to ground.
result.add_pillar(sidehead.id, jp, pradius);
}
if(jp(Z) < jsh(Z)) result.add_junction(jp, hbr);
if(jn(Z) >= jh(Z)) result.add_junction(jn, hbr);
double r_pillar = sidehead.request_pillar_radius(pradius);
result.add_bridge(jp, jn, r_pillar);
}
}
}
// We will break down the pillar positions in 2D into concentric rings.
// Connecting the pillars belonging to the same ring will prevent
// bridges from crossing each other. After bridging the rings we can
// create bridges between the rings without the possibility of crossing
// bridges. Two pillars will be bridged with X shaped stick pairs.
// If they are really close to each other, than only one stick will be
// used in zig-zag mode.
// Breaking down the points into rings will be done with a modified
// convex hull algorithm (see pts_convex_hull()), that works for
// collinear points as well. If the points are on the same surface,
// they can be part of an imaginary line segment for which the convex
// hull is not defined. I this case it is enough to sort the points
// spatially and create the bridge stick from the one endpoint to
// another.
ClusterEl rem = cl_centroids;
ClusterEl ring;
while(!rem.empty()) { // loop until all the points belong to some ring
tifcl();
std::sort(rem.begin(), rem.end());
auto newring = pts_convex_hull(rem,
[gnd_head_pt](unsigned i) {
auto&& p = gnd_head_pt(i);
return Vec2d(p(X), p(Y)); // project to 2D in along Z axis
});
if(!ring.empty()) {
// inner ring is now in 'newring' and outer ring is in 'ring'
SpatIndex innerring;
for(unsigned i : newring) { tifcl();
const Pillar& pill = result.head_pillar(gndidx[i]);
assert(pill.id >= 0);
innerring.insert(pill.endpoint, unsigned(pill.id));
}
// For all pillars in the outer ring find the closest in the
// inner ring and connect them. This will create the spider web
// fashioned connections between pillars
for(unsigned i : ring) { tifcl();
const Pillar& outerpill = result.head_pillar(gndidx[i]);
auto res = innerring.nearest(outerpill.endpoint, 1);
if(res.empty()) continue;
auto ne = res.front();
const Pillar& innerpill = result.pillars()[ne.second];
interconnect(outerpill, innerpill, emesh, result);
}
}
// no need for newring anymore in the current iteration
ring.swap(newring);
/*std::cout << "ring: \n";
for(auto ri : ring) {
std::cout << ri << " " << " X = " << gnd_head_pt(ri)(X)
<< " Y = " << gnd_head_pt(ri)(Y) << std::endl;
}
std::cout << std::endl;*/
// now the ring has to be connected with bridge sticks
for(auto it = ring.begin(), next = std::next(it);
next != ring.end();
++it, ++next)
{
tifcl();
const Pillar& pillar = result.head_pillar(gndidx[*it]);
const Pillar& nextpillar = result.head_pillar(gndidx[*next]);
interconnect(pillar, nextpillar, emesh, result);
}
auto sring = ring; ClusterEl tmp;
std::sort(sring.begin(), sring.end());
std::set_difference(rem.begin(), rem.end(),
sring.begin(), sring.end(),
std::back_inserter(tmp));
rem.swap(tmp);
}
};
// Step: routing the pinheads that are would connect to the model surface
// along the Z axis downwards. For now these will actually be connected with
// the model surface with a flipped pinhead. In the future here we could use
// some smart algorithms to search for a safe path to the ground or to a
// nearby pillar that can hold the supported weight.
auto routing_nongnd_fn = [tifcl](
const SupportConfig& cfg,
const std::vector<double>& gndheight,
const IndexSet& nogndidx,
Result& result)
{
// TODO: connect these to the ground pillars if possible
for(auto idx : nogndidx) { tifcl();
double gh = gndheight[idx];
double base_width = cfg.head_width_mm;
auto& head = result.head(idx);
// In this case there is no room for the base pinhead.
if(gh < head.fullwidth()) {
double min_l =
2 * cfg.head_front_radius_mm +
2 * cfg.head_back_radius_mm - cfg.head_penetration_mm;
base_width = gh - min_l;
}
if(base_width < 0) {
// There is really no space for even a reduced size head. We
// have to replace that with a small half sphere that touches
// the model surface. (TODO)
head.invalidate();
continue;
}
head.transform();
Vec3d headend = head.junction_point();
Head base_head(cfg.head_back_radius_mm,
cfg.head_front_radius_mm,
base_width,
cfg.head_penetration_mm,
{0.0, 0.0, 1.0},
{headend(X), headend(Y), headend(Z) - gh});
base_head.transform();
// Robustness check:
if(headend(Z) < base_head.junction_point()(Z)) {
// This should not happen it is against all assumptions
BOOST_LOG_TRIVIAL(warning)
<< "Ignoring invalid supports connecting to model body";
head.invalidate();
continue;
}
double hl = base_head.fullwidth() - head.r_back_mm;
result.add_pillar(idx,
Vec3d{headend(X), headend(Y), headend(Z) - gh + hl},
cfg.head_back_radius_mm
).base = base_head.mesh;
}
};
// Step: process the support points where there is not enough space for a
// full pinhead. In this case we will use a rounded sphere as a touching
// point and use a thinner bridge (let's call it a stick).
auto process_headless = [tifcl](
const SupportConfig& cfg,
const PointSet& headless_pts,
const PointSet& headless_norm,
const EigenMesh3D& emesh,
Result& result)
{
// For now we will just generate smaller headless sticks with a sharp
// ending point that connects to the mesh surface.
const double R = cfg.headless_pillar_radius_mm;
const double HWIDTH_MM = R/3;
// We will sink the pins into the model surface for a distance of 1/3 of
// the pin radius
for(int i = 0; i < headless_pts.rows(); i++) { tifcl();
Vec3d sph = headless_pts.row(i); // Exact support position
Vec3d n = headless_norm.row(i); // mesh outward normal
Vec3d sp = sph - n * HWIDTH_MM; // stick head start point
Vec3d dir = {0, 0, -1};
Vec3d sj = sp + R * n; // stick start point
// This is only for checking
double idist = bridge_mesh_intersect(sph, dir, R, emesh, true);
double dist = ray_mesh_intersect(sj, dir, emesh);
if(std::isinf(idist) || std::isnan(idist) || idist < 2*R ||
std::isinf(dist) || std::isnan(dist) || dist < 2*R) {
BOOST_LOG_TRIVIAL(warning) << "Can not find route for headless"
<< " support stick at: "
<< sj.transpose();
continue;
}
Vec3d ej = sj + (dist + HWIDTH_MM)* dir;
result.add_compact_bridge(sp, ej, n, R);
}
};
// Now that the individual blocks are defined, lets connect the wires. We
// will create an array of functions which represents a program. Place the
// step methods in the array and bind the right arguments to the methods
// This way the data dependencies will be easily traceable between
// individual steps.
// There will be empty steps as well like the begin step or the done or
// abort steps. These are slots for future initialization or cleanup.
using std::cref; // Bind inputs with cref (read-only)
using std::ref; // Bind outputs with ref (writable)
using std::bind;
// Here we can easily track what goes in and what comes out of each step:
// (see the cref-s as inputs and ref-s as outputs)
std::array<std::function<void()>, NUM_STEPS> program = {
[] () {
// Begin...
// Potentially clear up the shared data (not needed for now)
},
// Filtering unnecessary support points
bind(filterfn, cref(cfg), cref(points), cref(mesh),
ref(filtered_points), ref(head_normals),
ref(head_positions), ref(headless_positions), ref(headless_normals)),
// Pinhead generation
bind(pinheadfn, cref(cfg),
ref(head_positions), ref(head_normals), ref(result)),
// Classification of support points
bind(classifyfn, cref(cfg), cref(mesh),
ref(head_positions), ref(ground_heads), ref(noground_heads),
ref(head_heights), ref(ground_connectors), ref(result)),
// Routing ground connecting clusters
bind(routing_ground_fn,
cref(cfg), cref(ground_connectors), cref(ground_heads), cref(mesh),
ref(result)),
// routing non ground connecting support points
bind(routing_nongnd_fn, cref(cfg), cref(head_heights), cref(noground_heads),
ref(result)),
bind(process_headless,
cref(cfg), cref(headless_positions),
cref(headless_normals), cref(mesh),
ref(result)),
[] () {
// Done
},
[] () {
// Halt
},
[] () {
// Abort
}
};
Steps pc = BEGIN, pc_prev = BEGIN;
// Let's define a simple automaton that will run our program.
auto progress = [&ctl, &pc, &pc_prev] () {
static const std::array<std::string, NUM_STEPS> stepstr {
"Starting",
"Filtering",
"Generate pinheads",
"Classification",
"Routing to ground",
"Routing supports to model surface",
"Processing small holes",
"Done",
"Halt",
"Abort"
};
static const std::array<unsigned, NUM_STEPS> stepstate {
0,
10,
30,
50,
60,
70,
80,
100,
0,
0
};
if(ctl.stopcondition()) pc = ABORT;
switch(pc) {
case BEGIN: pc = FILTER; break;
case FILTER: pc = PINHEADS; break;
case PINHEADS: pc = CLASSIFY; break;
case CLASSIFY: pc = ROUTING_GROUND; break;
case ROUTING_GROUND: pc = ROUTING_NONGROUND; break;
case ROUTING_NONGROUND: pc = HEADLESS; break;
case HEADLESS: pc = DONE; break;
case HALT: pc = pc_prev; break;
case DONE:
case ABORT: break;
default: ;
}
ctl.statuscb(stepstate[pc], stepstr[pc]);
};
// Just here we run the computation...
while(pc < DONE || pc == HALT) {
progress();
program[pc]();
}
if(pc == ABORT) throw SLASupportsStoppedException();
return pc == ABORT;
}
SLASupportTree::SLASupportTree(): m_impl(new Impl()) {}
const TriangleMesh &SLASupportTree::merged_mesh() const
{
return get().merged_mesh();
}
void SLASupportTree::merged_mesh_with_pad(TriangleMesh &outmesh) const {
outmesh.merge(merged_mesh());
outmesh.merge(get_pad());
}
SlicedSupports SLASupportTree::slice(float layerh, float init_layerh) const
{
if(init_layerh < 0) init_layerh = layerh;
auto& stree = get();
const auto modelh = float(stree.full_height());
auto gndlvl = float(this->m_impl->ground_level);
const Pad& pad = m_impl->pad();
if(!pad.empty()) gndlvl -= float(get_pad_elevation(pad.cfg));
std::vector<float> heights;
heights.reserve(size_t(modelh/layerh) + 1);
for(float h = gndlvl + init_layerh; h < gndlvl + modelh; h += layerh) {
heights.emplace_back(h);
}
TriangleMesh fullmesh = m_impl->merged_mesh();
fullmesh.merge(get_pad());
TriangleMeshSlicer slicer(&fullmesh);
SlicedSupports ret;
slicer.slice(heights, &ret, get().ctl().cancelfn);
return ret;
}
const TriangleMesh &SLASupportTree::add_pad(const SliceLayer& baseplate,
const PoolConfig& pcfg) const
{
// PoolConfig pcfg;
// pcfg.min_wall_thickness_mm = min_wall_thickness_mm;
// pcfg.min_wall_height_mm = min_wall_height_mm;
// pcfg.max_merge_distance_mm = max_merge_distance_mm;
// pcfg.edge_radius_mm = edge_radius_mm;
return m_impl->create_pad(merged_mesh(), baseplate, pcfg).tmesh;
}
const TriangleMesh &SLASupportTree::get_pad() const
{
return m_impl->pad().tmesh;
}
void SLASupportTree::remove_pad()
{
m_impl->remove_pad();
}
SLASupportTree::SLASupportTree(const PointSet &points,
const EigenMesh3D& emesh,
const SupportConfig &cfg,
const Controller &ctl):
m_impl(new Impl(ctl))
{
m_impl->ground_level = emesh.ground_level() - cfg.object_elevation_mm;
generate(points, emesh, cfg, ctl);
}
SLASupportTree::SLASupportTree(const SLASupportTree &c):
m_impl(new Impl(*c.m_impl)) {}
SLASupportTree &SLASupportTree::operator=(const SLASupportTree &c)
{
m_impl = make_unique<Impl>(*c.m_impl);
return *this;
}
SLASupportTree::~SLASupportTree() {}
SLASupportsStoppedException::SLASupportsStoppedException():
std::runtime_error("") {}
}
}