diff --git a/src/libslic3r/SLA/SLAConcurrency.hpp b/src/libslic3r/SLA/SLAConcurrency.hpp
index cd45ce83e..4beb2aead 100644
--- a/src/libslic3r/SLA/SLAConcurrency.hpp
+++ b/src/libslic3r/SLA/SLAConcurrency.hpp
@@ -10,7 +10,7 @@ namespace sla {
 
 // Set this to true to enable full parallelism in this module.
 // Only the well tested parts will be concurrent if this is set to false.
-const constexpr bool USE_FULL_CONCURRENCY = false;
+const constexpr bool USE_FULL_CONCURRENCY = true;
 
 template<bool> struct _ccr {};
 
diff --git a/src/libslic3r/SLA/SLASupportTreeBuilder.cpp b/src/libslic3r/SLA/SLASupportTreeBuilder.cpp
index 9e1f8c1da..3fa9f3b98 100644
--- a/src/libslic3r/SLA/SLASupportTreeBuilder.cpp
+++ b/src/libslic3r/SLA/SLASupportTreeBuilder.cpp
@@ -360,6 +360,66 @@ const TriangleMesh &SupportTreeBuilder::add_pad(const ExPolygons &modelbase,
     return m_pad.tmesh;
 }
 
+SupportTreeBuilder::SupportTreeBuilder(SupportTreeBuilder &&o)
+    : m_heads(std::move(o.m_heads))
+    , m_head_indices{std::move(o.m_head_indices)}
+    , m_pillars{std::move(o.m_pillars)}
+    , m_bridges{std::move(o.m_bridges)}
+    , m_crossbridges{std::move(o.m_crossbridges)}
+    , m_compact_bridges{std::move(o.m_compact_bridges)}
+    , m_pad{std::move(o.m_pad)}
+    , m_meshcache{std::move(o.m_meshcache)}
+    , m_meshcache_valid{o.m_meshcache_valid}
+    , m_model_height{o.m_model_height}
+    , ground_level{o.ground_level}
+{}
+
+SupportTreeBuilder::SupportTreeBuilder(const SupportTreeBuilder &o)
+    : m_heads(o.m_heads)
+    , m_head_indices{o.m_head_indices}
+    , m_pillars{o.m_pillars}
+    , m_bridges{o.m_bridges}
+    , m_crossbridges{o.m_crossbridges}
+    , m_compact_bridges{o.m_compact_bridges}
+    , m_pad{o.m_pad}
+    , m_meshcache{o.m_meshcache}
+    , m_meshcache_valid{o.m_meshcache_valid}
+    , m_model_height{o.m_model_height}
+    , ground_level{o.ground_level}
+{}
+
+SupportTreeBuilder &SupportTreeBuilder::operator=(SupportTreeBuilder &&o)
+{
+    m_heads = std::move(o.m_heads);
+    m_head_indices = std::move(o.m_head_indices);
+    m_pillars = std::move(o.m_pillars);
+    m_bridges = std::move(o.m_bridges);
+    m_crossbridges = std::move(o.m_crossbridges);
+    m_compact_bridges = std::move(o.m_compact_bridges);
+    m_pad = std::move(o.m_pad);
+    m_meshcache = std::move(o.m_meshcache);
+    m_meshcache_valid = o.m_meshcache_valid;
+    m_model_height = o.m_model_height;
+    ground_level = o.ground_level;
+    return *this;
+}
+
+SupportTreeBuilder &SupportTreeBuilder::operator=(const SupportTreeBuilder &o)
+{
+    m_heads = o.m_heads;
+    m_head_indices = o.m_head_indices;
+    m_pillars = o.m_pillars;
+    m_bridges = o.m_bridges;
+    m_crossbridges = o.m_crossbridges;
+    m_compact_bridges = o.m_compact_bridges;
+    m_pad = o.m_pad;
+    m_meshcache = o.m_meshcache;
+    m_meshcache_valid = o.m_meshcache_valid;
+    m_model_height = o.m_model_height;
+    ground_level = o.ground_level;
+    return *this;
+}
+
 const TriangleMesh &SupportTreeBuilder::merged_mesh() const
 {
     if (m_meshcache_valid) return m_meshcache;
diff --git a/src/libslic3r/SLA/SLASupportTreeBuilder.hpp b/src/libslic3r/SLA/SLASupportTreeBuilder.hpp
index 7f38cf280..e967f5ea7 100644
--- a/src/libslic3r/SLA/SLASupportTreeBuilder.hpp
+++ b/src/libslic3r/SLA/SLASupportTreeBuilder.hpp
@@ -287,7 +287,11 @@ public:
     double ground_level = 0;
     
     SupportTreeBuilder() = default;
-    
+    SupportTreeBuilder(SupportTreeBuilder &&o);
+    SupportTreeBuilder(const SupportTreeBuilder &o);
+    SupportTreeBuilder& operator=(SupportTreeBuilder &&o);
+    SupportTreeBuilder& operator=(const SupportTreeBuilder &o);
+
     template<class...Args> Head& add_head(unsigned id, Args&&... args)
     {
         std::lock_guard<Mutex> lk(m_mutex);
diff --git a/src/libslic3r/SLA/SLASupportTreeBuildsteps.cpp b/src/libslic3r/SLA/SLASupportTreeBuildsteps.cpp
index 72673babf..0ff26b3ac 100644
--- a/src/libslic3r/SLA/SLASupportTreeBuildsteps.cpp
+++ b/src/libslic3r/SLA/SLASupportTreeBuildsteps.cpp
@@ -213,7 +213,7 @@ EigenMesh3D::hit_result SupportTreeBuildsteps::pinhead_mesh_intersect(
     // 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
-    ccr_par::enumerate(
+    ccr::enumerate(
         phis.begin(), phis.end(),
         [&hits, &m, sd, r_pin, r_back, s, a, b, c](double phi, size_t i) {
            double sinphi = std::sin(phi);
@@ -310,7 +310,7 @@ EigenMesh3D::hit_result SupportTreeBuildsteps::bridge_mesh_intersect(
     // Hit results
     std::array<HitResult, SAMPLES> hits;
     
-    ccr_par::enumerate(
+    ccr::enumerate(
         phis.begin(), phis.end(),
         [&m, a, b, sd, dir, r, s, ins_check, &hits] (double phi, size_t i) {
             double sinphi = std::sin(phi);