topic Re: RVertex from MNMesh in 3ds Max Programming Forum

RVertex from MNMesh

Anonymous — Thu, 05 Nov 2015 22:12:35 GMT

I'm trying to read out the normals for a given vertex in a given face inside an MNMesh. The MNMesh::GetVertexNormal(..) is the averaged normal, which isn't what I want.

Basically I'm searching for the RVertex for a given vertex inside a given face. I know how to do this for a regular Mesh, but somehow I can't find how to do this for an MNMesh object. Does anyone perhaps know?

I need to use MNMesh as I don't want the triangulated mesh, but the poly mesh.

Re: RVertex from MNMesh

Anonymous — Thu, 05 Nov 2015 22:42:32 GMT

I solved it with a bit of a hack, assuming it is safe.

I keep the triangle mesh next to the poly mesh, assuming they have the same vertex order and I get the actual normals from the mesh now, that seems to work well.

Re: RVertex from MNMesh

michael_lawler — Mon, 14 Dec 2015 18:12:51 GMT

Hello,

Would you mind posting your method to resolve this? I am currently in the same situation where I want to calculate the MNMesh's vertex normals using Smooth Groups... and as you figured out-- its RVertex member is private and inaccessible (wtf Autodesk?)...

...anyways, I have the vertex normals exporting properly when there are specified/explicit vertex normals (via an Edit_Normals Modifier) using class MNNormalSpec... but I can't get the correct normals when I want them based on smoothing groups.

Any help would be greatly appreciated. Thanks!

Re: RVertex from MNMesh

Anonymous — Mon, 14 Dec 2015 18:22:26 GMT

Hi,

What I did was a super hack, and it works only in like 90% of the cases.

Next to having the MNMesh I keep a triangle mesh as well, using the other mesh/trimesh class.

And I first check if the vertex count in both meshes is the same.

If it is the same, which it is in most cases, I get the normals from the triangle mesh for the given vertex numbers.

That works good in all cases I tested.

I use it to export mesh data to a custom format.

In case the vertex counts in the triangle mesh and MNMesh are different, I force exporting the triangle mesh.

It is not how it should all be, obviously a mega hack and it doesn't even work in 100% of the cases as sometimes magically the vertex counts are very different (not sure why, I tried deleting dead vertices etc already in MNMesh).

For me it is an ok workaround now, but I would also really like to do this properly and just get the vertex normal from the MNMesh directly. Next to this I had other issues as well. I felt like I was the first one to ever use that class. Really bad from Autodesk in my eyes.

In Maya this works so much cleaner 🙂 They should just let Max die as it is one super hack that evolved from the same code base as the initial MS-Dos version if you ask me 🙂

Re: RVertex from MNMesh

michael_lawler — Tue, 15 Dec 2015 16:18:06 GMT

I think I may have a better solution that will work all the time... I will try it out this evening. Basically, use the MNNormalSpec pointer to the MNMesh... and if the MNNormalSpec pointer returns NULL... immediately make all normals specifed using:

MNMesh mnmesh(*pMesh);
mnmesh.MakePolyMesh();
mnmesh.EliminateBadVerts ();
mnmesh.EliminateDoubledMappingVerts();
mnmesh.EliminateIsoMapVerts();

MNNormalSpec *nspec = mnmesh->GetSpecifiedNormals();

if (nspec == NULL)
{
      mnmesh->SpecifyNormals(false, NULL); //make all unspecified normals-- specified
      nspec = mnmesh->GetSpecifiedNormals();
      nspec->CheckNormals();
}

// iterate thru faces/vertexes and get the normal from nspec