Max 2020 and VRay 3.70.01: crash when rendering empty mesh?

[tysonibele]

I have a scene with a tySpline object (from tyFlow) that has a tySplineMesher modifier on top of it that is crashing during light initialization. When the tySplineMesher is removed, it renders fine. The tySplineMesher for the first chunk of frames in the sequence is not generating any mesh so it leaves the object empty. Any ideas why this is occurring?

Attached is the minidump, as well as the scene. If you open the scene and render frame 10, for example, it should crash during initialization of VRayLight001.

[yavor.rubenov]

Hello,

In my test the mesh is not exactly empty - its faces member (Mesh::faces) is not nullptr but contains invalid data. Unfortunately we use it to check if the mesh is valid like this:

if (!mesh.faces) {
   return Point3(0.0f, 0.0f, 0.0f);
}

Probably we could add checks for numFaces and numVerts and that will fix the crash but ideally faces should also be nullptr.

Best regards,
Yavor

[tysonibele]

Thanks Yavor,

That helped me track down where the issue is occurring.

Might be worth adding that check for numFaces...in my tests here calling mesh.setNumFaces(0) actually initializes the faces array even if it was previously set to null, which is weird and is seemingly what was causing the issue. Although I'm getting some inconsistent results in that regard, so perhaps my debugger is reporting things incorrectly....either way, re-nulling faces before handing off the mesh through the modifier seems to have fixed the crashing.