3DPrinting/PrusaSlicer-NonPlainar
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Document extensively the generated SupportPoint structure,

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fix wrong estimation of weight torque for connections
This commit is contained in:
PavelMikus 2023-01-19 15:07:06 +01:00
parent 6d37c505f7
commit be61ab37f4
2 changed files with 35 additions and 6 deletions
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19
src/libslic3r/SupportSpotsGenerator.cpp
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@ -463,7 +463,7 @@ public:
#ifdef DETAILED_DEBUG_LOGS
BOOST_LOG_TRIVIAL(debug) << "bed_centroid: " << bed_centroid.x() << " " << bed_centroid.y() << " " << bed_centroid.z();
BOOST_LOG_TRIVIAL(debug) << "SSG: bed_yield_torque: " << bed_yield_torque;
BOOST_LOG_TRIVIAL(debug) << "SSG: bed_weight_arm: " << bed_weight_arm;
BOOST_LOG_TRIVIAL(debug) << "SSG: bed_weight_arm: " << bed_weight_arm_len;
BOOST_LOG_TRIVIAL(debug) << "SSG: bed_weight_torque: " << bed_weight_torque;
BOOST_LOG_TRIVIAL(debug) << "SSG: bed_movement_arm: " << bed_movement_arm;
BOOST_LOG_TRIVIAL(debug) << "SSG: bed_movement_torque: " << bed_movement_torque;
@ -492,7 +492,7 @@ public:
params.material_yield_strength;
float conn_weight_arm = (conn_centroid.head<2>() - mass_centroid.head<2>()).norm();
float conn_weight_torque = conn_weight_arm * weight * (conn_centroid.z() / layer_z);
float conn_weight_torque = conn_weight_arm * weight * (1.0f - conn_centroid.z() / layer_z);
float conn_movement_arm = std::max(0.0f, mass_centroid.z() - conn_centroid.z());
float conn_movement_torque = movement_force * conn_movement_arm;
@ -732,17 +732,24 @@ SupportPoints check_stability(const PrintObject *po, const PrintTryCancel& cance
// and the support presence grid and add the point to the issues.
auto reckon_new_support_point = [&part, &weakest_conn, &supp_points, &supports_presence_grid, &params,
&layer_idx](const Vec3f &support_point, float force, const Vec2f &dir) {
// if position is taken and point is for global stability (force > 0) or we are too close to the bed, do not add
// This allows local support points (e.g. bridging) to be generated densely
if ((supports_presence_grid.position_taken(support_point) && force > 0) || layer_idx <= 1) {
return;
}
float area = params.support_points_interface_radius * params.support_points_interface_radius * float(PI);
part.add_support_point(support_point, area);
// add the stability effect of the point only if the spot is not taken, so that the densely created local support points do not add
// unrealistic amount of stability to the object (due to overlaping of local support points)
if (!(supports_presence_grid.position_taken(support_point))) {
part.add_support_point(support_point, area);
}
float radius = params.support_points_interface_radius;
supp_points.emplace_back(support_point, force, radius, dir);
if (force > 0) {
supports_presence_grid.take_position(support_point);
}
supports_presence_grid.take_position(support_point);
// The support point also increases the stability of the weakest connection of the object, which should be reflected
if (weakest_conn.area > EPSILON) { // Do not add it to the weakest connection if it is not valid - does not exist
weakest_conn.area += area;
weakest_conn.centroid_accumulator += support_point * area;

22
src/libslic3r/SupportSpotsGenerator.hpp
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@ -63,11 +63,33 @@ struct Params {
}
};
// The support points are generated for two reasons:
// 1. Local extrusion support for extrusions that are printed in the air and would not
// withstand on their own (too long bridges, sharp turns in large overhang, concave bridge holes, etc.)
// These points have negative force (-EPSILON) and Vec2f::Zero() direction
// The algorithm still expects that these points will be supported and accounts for them in the global stability check
// 2. Global stability support points are generated at each spot, where the algorithm detects that extruding the current line
// may cause separation of the object part from the bed and/or its support spots or crack in the weak connection of the object parts
// The generated point's direction is the estimated falling direction of the object part, and the force is equal to te difference
// between forces that destabilize the object (extruder conflicts with curled filament, weight if instable center of mass, bed movements etc)
// and forces that stabilize the object (bed adhesion, other support spots adhesion, weight if stable center of mass)
// Note that the force is only the difference - the amount needed to stabilize the object again.
struct SupportPoint {
SupportPoint(const Vec3f &position, float force, float spot_radius, const Vec2f &direction);
bool is_local_extrusion_support() const { return force < 0; }
bool is_global_object_support() const { return !is_local_extrusion_support(); }
//position is in unscaled coords. The z coordinate is aligned with the layers bottom_z coordiantes
Vec3f position;
// force that destabilizes the object to the point of falling/breaking. It is in g*mm/s^2 units
// values gathered from large XL print: Min : 0 | Max : 18713800 | Average : 1361186 | Median : 329103
// For reference 18713800 is weight of 1.8 Kg object, 329103 is weight of 0.03 Kg
// The final printed object weight was approx 0.5 Kg
float force;
// Expected spot size. The support point strength is calculated from the area defined by this value.
// Currently equal to the support_points_interface_radius parameter above
float spot_radius;
// direction of the fall of the object (z part is neglected)
Vec2f direction;
};