opt untangle() (cdc7919d) · Commits · Intelligent 3D Graphics / Fast Tetrahedral Meshing in the Wild

src/MeshImprovement.cpp

+75 −13

Original line number	Diff line number	Diff line
		@@ -1365,6 +1365,8 @@ void floatTetWild::untangle(Mesh &mesh) {
		auto &tet_vertices = mesh.tet_vertices;
		auto &tets = mesh.tets;
		static const Scalar zero_area = 1e2 * SCALAR_ZERO_2;
		static const std::vector<std::array<int, 4>> face_pairs = {{{0, 1, 2, 3}}, {{0, 2, 1, 3}}, {{0, 3, 1, 2}}};


		int cnt = 0;
		for (int t_id = 0;t_id<tets.size();t_id++) {
		@@ -1373,14 +1375,14 @@ void floatTetWild::untangle(Mesh &mesh) {
		continue;
		if (t.quality < 1e10)
		continue;
		bool is_on_surface = false;
		int cnt_on_surface = 0;
		bool has_degenerate_face = false;
		std::array<double, 4> areas;
		double max_area = 0;
		double max_j = -1;
		int max_j = -1;
		for (int j = 0; j < 4; j++) {
		if (t.is_surface_fs[j] != NOT_SURFACE)
		is_on_surface = true;
		cnt_on_surface++;
		areas[j] = get_area(tet_vertices[t[(j + 1) % 4]].pos,
		tet_vertices[t[(j + 2) % 4]].pos,
		tet_vertices[t[(j + 3) % 4]].pos);
		@@ -1391,7 +1393,27 @@ void floatTetWild::untangle(Mesh &mesh) {
		max_j = j;
		}
		}
		if (is_on_surface && has_degenerate_face && t.is_surface_fs[max_j] != NOT_SURFACE && max_area > zero_area) {
		if (cnt_on_surface == 0)
		continue;

		if (has_degenerate_face) {
		if (t.is_surface_fs[max_j] != NOT_SURFACE && max_area > zero_area) {
		for (int j = 0; j < 4; j++) {
		if (j != max_j) {
		t.is_surface_fs[j] = NOT_SURFACE;
		int opp_t_id = get_opp_t_id(mesh, t_id, j);
		if (opp_t_id >= 0) {
		int k = get_local_f_id(opp_t_id, t[(j + 1) % 4], t[(j + 2) % 4], t[(j + 3) % 4], mesh);
		tets[opp_t_id].is_surface_fs[k] = NOT_SURFACE;
		}
		}
		}
		cnt++;
		}
		} else {
		if (cnt_on_surface <= 2)
		continue;
		if (max_area - areas[(max_j + 1) % 4] - areas[(max_j + 2) % 4] - areas[(max_j + 3) % 4] < zero_area) {
		for (int j = 0; j < 4; j++) {
		if (j != max_j) {
		t.is_surface_fs[j] = NOT_SURFACE;
		@@ -1402,8 +1424,48 @@ void floatTetWild::untangle(Mesh &mesh) {
		}
		}
		}
		cnt++;
		} else {
		for (const auto &fp: face_pairs) {
		std::array<Vector3, 2> ns;
		auto& p1 = tet_vertices[tets[t_id][fp[2]]].pos;
		auto& p2 = tet_vertices[tets[t_id][fp[3]]].pos;
		Vector3 v = (p2-p1).normalized();
		for(int j=0;j<2;j++){
		auto& p = tet_vertices[tets[t_id][fp[j]]].pos;
		Vector3 q = p1+((p-p1).dot(v))*v;
		ns[j] = p-q;
		}
		if(ns[0].dot(ns[1])>0)
		continue;

		if (areas[fp[0]] + areas[fp[1]] - areas[fp[2]] - areas[fp[3]] > zero_area)
		continue;

		std::array<int, 2> js = {{-1, -1}};
		if (t.is_surface_fs[fp[0]] != NOT_SURFACE && t.is_surface_fs[fp[1]] != NOT_SURFACE)
		js = {{fp[2], fp[3]}};
		else if (t.is_surface_fs[fp[2]] != NOT_SURFACE && t.is_surface_fs[fp[3]] != NOT_SURFACE)
		js = {{fp[0], fp[1]}};

		for (int j: js) {
		if (j < 0)
		continue;
		if (t.is_surface_fs[j] == NOT_SURFACE)
		continue;
		t.is_surface_fs[j] = NOT_SURFACE;
		int opp_t_id = get_opp_t_id(mesh, t_id, j);
		if (opp_t_id >= 0) {
		int k = get_local_f_id(opp_t_id, t[(j + 1) % 4], t[(j + 2) % 4], t[(j + 3) % 4], mesh);
		tets[opp_t_id].is_surface_fs[k] = NOT_SURFACE;
		}
		}
		if(js[0]>=0)//fortest
		cnt++;
		break;
		}
		}
		}
		}
		pausee("fixed " + std::to_string(cnt) + " tangled element");
		cout<<"fixed " + std::to_string(cnt) + " tangled element"<<endl;
		}