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Vertex normal smoothing in CGAL --cgal-smooth-angle-degrees #6997

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This commit is contained in:
Thomas Krijnen
2025-08-06 05:46:07 +02:00
parent d1bcd887ca
commit 071353eddc
2 changed files with 55 additions and 9 deletions
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src/ifcgeom/ConversionSettings.h
+7 -1
View File
@@ -364,6 +364,12 @@ namespace ifcopenshell {
static constexpr int defaultvalue = 16;
};
struct CgalSmoothAngleDegrees : public SettingBase<CgalSmoothAngleDegrees, double> {
static constexpr const char* const name = "cgal-smooth-angle-degrees";
static constexpr const char* const description = "Angle in degrees under which adjacent facets will have averaged vertex normals in CGAL output. NB irrespective of original IFC geometry types. Defaults to -1 to disable smoothing.";
static constexpr int defaultvalue = -1.;
};
struct KeepBoundingBoxes : public SettingBase<KeepBoundingBoxes, bool> {
static constexpr const char* const name = "keep-bounding-boxes";
static constexpr const char* const description =
@@ -640,7 +646,7 @@ namespace ifcopenshell {
};
class IFC_GEOM_API Settings : public SettingsContainer<
std::tuple<MesherLinearDeflection, MesherAngularDeflection, ReorientShells, LengthUnit, PlaneUnit, Precision, OutputDimensionality, LayersetFirst, DisableBooleanResult, NoWireIntersectionCheck, NoWireIntersectionTolerance, PrecisionFactor, DebugBooleanOperations, BooleanAttempt2d, SurfaceColour, WeldVertices, UseWorldCoords, UnifyShapes, UseMaterialNames, ConvertBackUnits, ContextIds, ContextTypes, ContextIdentifiers, IteratorOutput, DisableOpeningSubtractions, ApplyDefaultMaterials, DontEmitNormals, GenerateUvs, ApplyLayerSets, UseElementHierarchy, ValidateQuantities, EdgeArrows, BuildingLocalPlacement, SiteLocalPlacement, ForceSpaceTransparency, CircleSegments, KeepBoundingBoxes, ComputeCurvature, FunctionStepType, FunctionStepParam, NoParallelMapping, PermissiveShapeReuse, ModelOffset, ModelRotation, TriangulationType, CgalEmitOriginalEdges, OcctNoCleanTriangulation, CacheShapes, DeferProcessingFirstElement, MaxOffset, MaxOffsetDeviation, ApplyOffset>
std::tuple<MesherLinearDeflection, MesherAngularDeflection, ReorientShells, LengthUnit, PlaneUnit, Precision, OutputDimensionality, LayersetFirst, DisableBooleanResult, NoWireIntersectionCheck, NoWireIntersectionTolerance, PrecisionFactor, DebugBooleanOperations, BooleanAttempt2d, SurfaceColour, WeldVertices, UseWorldCoords, UnifyShapes, UseMaterialNames, ConvertBackUnits, ContextIds, ContextTypes, ContextIdentifiers, IteratorOutput, DisableOpeningSubtractions, ApplyDefaultMaterials, DontEmitNormals, GenerateUvs, ApplyLayerSets, UseElementHierarchy, ValidateQuantities, EdgeArrows, BuildingLocalPlacement, SiteLocalPlacement, ForceSpaceTransparency, CircleSegments, CgalSmoothAngleDegrees, KeepBoundingBoxes, ComputeCurvature, FunctionStepType, FunctionStepParam, NoParallelMapping, PermissiveShapeReuse, ModelOffset, ModelRotation, TriangulationType, CgalEmitOriginalEdges, OcctNoCleanTriangulation, CacheShapes, DeferProcessingFirstElement, MaxOffset, MaxOffsetDeviation, ApplyOffset>
>
{};
}
src/ifcgeom/kernels/cgal/CgalConversionResult.cpp
+48 -8
View File
@@ -217,6 +217,14 @@ void ifcopenshell::geometry::CgalShape::Triangulate(ifcopenshell::geometry::Sett
}
}
boost::optional<double> smooth_treshold;
{
auto setting_value = settings.get<ifcopenshell::geometry::settings::CgalSmoothAngleDegrees>().get();
if (setting_value > 0.) {
smooth_treshold = std::cos(setting_value * boost::math::constants::pi<double>() / 180.0);
}
}
if (!all_triangles) {
if (!shape_to_use->is_valid()) {
Logger::Message(Logger::LOG_ERROR, "Invalid Polyhedron_3 in object (before triangulation)");
@@ -261,8 +269,8 @@ void ifcopenshell::geometry::CgalShape::Triangulate(ifcopenshell::geometry::Sett
// boost::associative_property_map<std::map<cgal_vertex_descriptor_t, Kernel_::Vector_3>> vertex_normals_map(vertex_normals);
// Triangulate the shape and compute the normals
std::map<cgal_face_descriptor_t, Kernel_::Vector_3> face_normals;
boost::associative_property_map<std::map<cgal_face_descriptor_t, Kernel_::Vector_3>> face_normals_map(face_normals);
std::map<Facet_const_handle, Kernel_::Vector_3> face_normals;
boost::associative_property_map<std::map<Facet_const_handle, Kernel_::Vector_3>> face_normals_map(face_normals);
// CGAL::Polygon_mesh_processing::compute_normals(s, vertex_normals_map, face_normals_map);
try {
@@ -286,17 +294,49 @@ void ifcopenshell::geometry::CgalShape::Triangulate(ifcopenshell::geometry::Sett
continue;
}
CGAL::Polyhedron_3<Kernel_>::Halfedge_around_facet_const_circulator current_halfedge = face->facet_begin();
const Kernel_::Vector_3 facet_normal = face_normals_map[face];
int vertexidx[3];
bool is_face_boundary[3];
int i = 0;
do {
auto v = current_halfedge->vertex();
auto vertex_norm = facet_normal;
if (smooth_treshold) {
Kernel_::Vector_3 normal_accum(0, 0, 0);
{
// circulator around the vertex
auto vh_begin = v->vertex_begin();
if (vh_begin != nullptr) {
auto vh = vh_begin;
do {
if (!vh->is_border()) {
Facet_const_handle adj_f = vh->facet();
const auto fn2 = face_normals_map[adj_f];
if ((fn2 * facet_normal) >= *smooth_treshold) {
normal_accum = normal_accum + fn2;
}
++vh;
}
} while (vh != vh_begin);
}
}
const double len = std::sqrt(CGAL::to_double(normal_accum.squared_length()));
if (len > 0) {
vertex_norm = normal_accum / len;
}
}
postion_normal pn = {
current_halfedge->vertex()->point().cartesian(0),
current_halfedge->vertex()->point().cartesian(1),
current_halfedge->vertex()->point().cartesian(2),
face_normals_map[face].cartesian(0),
face_normals_map[face].cartesian(1),
face_normals_map[face].cartesian(2)
v->point().cartesian(0),
v->point().cartesian(1),
v->point().cartesian(2),
vertex_norm.cartesian(0),
vertex_norm.cartesian(1),
vertex_norm.cartesian(2)
};
// @todo normalzie based on largest component?