TriangulateFace takes several arguments (cf. https://docs.techsoft3d.com/communicator/latest/build/api_ref/data_import/libsc/namespaceSC_1_1Store_1_1Utils.html#a10002aedb0ee2764603e5f5c0f5b9e07 SC::Store::Utils::TriangulateFace ) to triangulate a supplied polygonal face. While most arguments are straightforward, the face_list is a little more complicated.
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{ 3, 0, 1, 2,
3, 2, 3, 0 } |
\uD83D\uDCD8 Instructions
Simple Example
Lets assume we have a single polygon with 300 points (nb_circle_steps). This is all in one “face”. So, the correct code for this would be
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std::vector<int> face_list;
face_list.push_back(nb_circle_steps);
for (uint32_t i = 0; i < nb_circle_steps; i++)
face_list.push_back(i);
std::vector<SC::Store::Point> out_points;
bool triStatus = SC::Store::Utils::TriangulateFace(mesh_points.data(), face_list.data(), face_list.size(), SC::Store::Point(0, 0, 1), out_points);
if (triStatus)
std::cout << "TriangulateFace : out_points count = " << out_points.size() << std::endl;
else
std::cout << "TriangulateFace : failed" << std::endl; |
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Notice |
Concave Faces
This is the only triangulation function available in Communicator and it handles concave polygons. Consider this simple test.
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int point_count = 5;
std::vector<int> face_list;
face_list.push_back(point_count);
for (uint32_t i = 0; i < point_count; i++)
face_list.push_back(i);
std::vector<SC::Store::Point> poly_points;
poly_points.resize(point_count);
poly_points[0].x = 0;
poly_points[0].y = 0;
poly_points[0].z = 0;
poly_points[1].x = 1;
poly_points[1].y = 1;
poly_points[1].z = 0;
poly_points[2].x = 2;
poly_points[2].y = 0;
poly_points[2].z = 0;
poly_points[3].x = 1;
poly_points[3].y = 2;
poly_points[3].z = 0;
poly_points[4].x = 0;
poly_points[4].y = 0;
poly_points[4].z = 0;
std::vector<SC::Store::Point> out_points;
bool triStatus = SC::Store::Utils::TriangulateFace(poly_points.data(), face_list.data(), face_list.size(), SC::Store::Point(0, 0, 1), out_points); |
The result was
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+ [0] {x=1.00000000 y=2.00000000 z=0.00000000 } SC::Store::Point
+ [1] {x=0.00000000 y=0.00000000 z=0.00000000 } SC::Store::Point
+ [2] {x=1.00000000 y=1.00000000 z=0.00000000 } SC::Store::Point
+ [3] {x=1.00000000 y=2.00000000 z=0.00000000 } SC::Store::Point
+ [4] {x=1.00000000 y=1.00000000 z=0.00000000 } SC::Store::Point
+ [5] {x=2.00000000 y=0.00000000 z=0.00000000 } SC::Store::Point |
Faces with Holes
This method supports holes as well. It expects more than one face passed in where one face represents the perimeter and subsequent faces represent holes. Simply negate the first parameter in the face list for a face which represents a hole.
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int perim_count = 4;
int hole_count = 4;
int point_count = perim_count + hole_count;
std::vector<int> face_list;
for (uint32_t i = 0; i < point_count; i++)
{
if (i == 0)
face_list.push_back(perim_count);
else if (i == 4)
face_list.push_back(-hole_count); // negated parameter indicates this face is a hole
face_list.push_back(i);
}
std::vector<SC::Store::Point> poly_points;
poly_points.push_back(SC::Store::Point(0, 0, 0)); // perimeter
poly_points.push_back(SC::Store::Point(3, 0, 0));
poly_points.push_back(SC::Store::Point(3, 3, 0));
poly_points.push_back(SC::Store::Point(0, 3, 0));
poly_points.push_back(SC::Store::Point(1, 1, 0)); // hole
poly_points.push_back(SC::Store::Point(2, 1, 0));
poly_points.push_back(SC::Store::Point(2, 2, 0));
poly_points.push_back(SC::Store::Point(1, 2, 0));
std::vector<SC::Store::Point> out_points;
bool triStatus = SC::Store::Utils::TriangulateFace(poly_points.data(), face_list.data(), face_list.size(), SC::Store::Point(0, 0, 1), out_points);
if (triStatus)
std::cout << "TriangulateFace : out_points count = " << out_points.size() << std::endl;
else
std::cout << "TriangulateFace : failed" << std::endl;
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\uD83D\uDCCB Related articles
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For the full example, check out our forum post.