How to programmatically bevel mesh edges

[JihoKang24]

Hi developers,

I came across this issue: #1210

In our case, we need to use the edge bevel feature programmatically in our C++ code.

Could you please provide any guidance or examples on how to access this feature through the MeshLib API?

Thanks in advance — really appreciate the great work you’re doing on this project!

[Grantim]

Hello!

Unfortunately that feature was not finished, and also was deprioritized, so we have not complete function. But if you need smooth corners, you can try this function:

MeshLib/source/MRVoxels/MRVDBConversions.h

Lines 183 to 185 in 5fd52ea

	/// performs convention from mesh to voxel grid and back with offsetA, and than same with offsetB;
	/// if input mesh is not closed then the sign of distance field will be obtained using generalized winding number computation
	MRVOXELS_API Expected<Mesh> doubleOffsetVdb( const MeshPart& mp, const DoubleOffsetSettings & settings );

Positive + negative will smooth concave edges
Negative + positive will smooth convex edges

Also we will consider putting mesh-based function in our roadmap.

[JihoKang24]

Hi grantim I'm so late for this answer

In our case we have to create this function. then
this is my tried code

	EdgePath edgePathBeforeTrim = mesh.topology.findHoleRepresentiveEdges();
	// 남길 메쉬쪽으로 plane의 normal 방향이 향해야한다.
	TrimWithPlaneParams params;
	{
		Plane3f plane = Plane3f();
		Vector3f v3PlanNormal = -VxConvertVxDouble3ToVector3f(d3PlaneNormal);
		Vector3f v3PlaneCenter = VxConvertVxDouble3ToVector3f(d3PlaneCenter);
		plane.n = v3PlanNormal;
		plane.d = dot(plane.n, v3PlaneCenter);
		params.plane = plane;
	}

	TrimOptionalOutput Output;
	EdgeLoops outCutContours = EdgeLoops();
	Output.outCutContours = &outCutContours;
	// cut plane
	trimWithPlane(mesh, params, Output);
	Mesh mesh2 = mesh;

	// calc normal
	auto norms = computePerVertNormals(mesh);

	map<int, vector<vxdouble3>> mapCutPoints;

	EdgePath edgePathNeedFill = EdgePath();
	{
		EdgePath edgePathAfterTrim = mesh.topology.findHoleRepresentiveEdges();
		for (int i = 0; i < edgePathAfterTrim.size(); i++)
		{
			auto e = edgePathAfterTrim[i];
			if (find(edgePathBeforeTrim.begin(), edgePathBeforeTrim.end(), e) == edgePathBeforeTrim.end())
			{
				edgePathNeedFill.push_back(e);
			}
		}
	}

	VertBitSet vsVerts = mesh.topology.getValidVerts();
	vector<vxdouble3> vtrRollingApplyPoints;
	map<int, vector<vxdouble3>> mapGenerateSplineCurve;
	int i = 0;
	map<int, vector<vxdouble3>> mapFilletCurvePoints;

	vector<float> vtrPlaneOffsetDistance;
	for (auto edge : edgePathNeedFill)
	{
		EdgeLoop edgeLoop = trackRightBoundaryLoop(mesh.topology, edge);

		// compute hole center
		Vector3f v3Point;
		int cnt = 0;
#pragma omp parallel
		{
			Vector3f v3Local;
			int local_cnt = 0;

#pragma omp for
			for (int i = 0; i < edgeLoop.size(); ++i)
			{
				v3Local += mesh.orgPnt(edgeLoop[i]);
				local_cnt++;
			}


			// 각 스레드의 결과를 최종 결과에 더하는 부분
#pragma omp critical
			{
				v3Point += v3Local;
				cnt += local_cnt;
			}
		}
		v3Point /= (float)cnt;
		mapFilletCurvePoints[loopIdx].push_back(VxConverVector3fToVxDouble3(v3Point));

		float fSum = 0.0f;
		for (auto e : edgeLoop)
		{
			auto v = mesh.topology.org(e);
			auto vDest = mesh.topology.dest(e);
			auto tri = mesh.topology.getLeftTriVerts(e);
			int idx = -1;
			for (int i = 0; i < 3; i++)
			{
				if (tri[i] != v && tri[i] != vDest)
				{
					idx = i;
					break;
				}
			}

			if (idx == -1)
				continue;


			auto dir0 = (v3Point - mesh.points[v]).normalized();
			auto dir1 = params.plane.n;
			auto p0 = mesh.points[v] + dir0 * dFilletRadius;
			auto p1 = mesh.points[v] + dir1 * dFilletRadius;

			mapFilletCurvePoints[loopIdx].push_back(VxConverVector3fToVxDouble3(p0));
			mapFilletCurvePoints[loopIdx].push_back(VxConverVector3fToVxDouble3(p1));
		}
	}

this way is correct ? always appreciate for your helps

[Grantim]

Hello!

this way is correct ?

This code seems to trim mesh with plane, and fill the cut. Looks like it should work for single edge, but more complex cases might not work. So short answer is it's OK while it works for your cases, but not in general.

[JihoKang24]

always appreciate for your helps!! thank you grantim!!!