Error Setting UVs on MFnMesh

[Anonymous]

I have the code below, where I create a mesh, and try to set UVs

MFnMesh fnMeshCreator;
MObject meshMObj = fnMeshCreator.create(uniquePositionsList->Count, mesh->Triangles->Count, mPointArray, polygonCounts, polygonConnects, meshTransformObj);

MFnMesh fnMesh(meshMObj);

fnMesh.clearUVs();

if (fnMesh.setUVs(uArray, vArray) == MStatus::kFailure)
{
    cerr << "Always comes in here" << endl;
}

However, it always returns MStatus::kFailure when attempting to setUVs

Anyone know why?

Thank you

[Anonymous]

I think you have to create a uv set first.

MString uvSetName = MString("UVSet");
mesh.createUVSet(uvSetName);
mesh.clearUVs(&uvSetName);
mesh.setUVs(.., .., &uvSetName);

If this doesn't work you could try assignUVs(...)

[Anonymous]

Anything I do -- if I pass in MStatus object -- it is always setting it as MStatus Failure

[Anonymous]

I forgot this already, you must call assignUVs, this will connect the indices to the suitable uv's. When you have a unique uv coordinate for each vertex, then you can simply use the indices. You must also use the UV Linking Editor (select the object, then right mouse click->UV Set->UV Linking..) to choose your uv set (if you have mulitple uv sets)

MString uvSetName = MString("UVSet");
fnMeshCreator.createUVSet(uvSetName);
fnMeshCreator.setCurrentUVSetName(uvSetName); // When you call this, then you don't have to assign the name to the following methods

fnMeshCreator.clearUVs(&uvSetName);
fnMeshCreator.setUVs(Us, Us, &uvSetName);

// Here you use the your polygon Count array and indices (polygonConnects) from the original method, this means for each vertex you create

// a unique uv coordinate. From this follow the Us and Vs array must have the same number like your vertex/point array!

fnMeshCreator.assignUVs(polygonCount, polygonConnects, &uvSetName);

Which method returns a Failed? In which method you execute your code?

[Anonymous]

MObject meshMObj = fnMeshCreator.create(uniquePositionsList->Count, mesh->Triangles->Count, mPointArray, polygonCounts, polygonConnects, meshTransformObj, &status);

if (status == MStatus::kFailure)
{
  cerr << "Mesh create error" << endl;
}

MFnMesh fnMesh(meshMObj);

MString setName = "UVSet";

fnMesh.createUVSet(setName);
fnMesh.setCurrentUVSetName(setName);

fnMesh.getCurrentUVSetName(setName);

cerr << "Current setName after getCurrentUVSetName: " << setName.asChar() << endl;

if (fnMesh.setUVs(uArray, vArray, &setName) == MStatus::kFailure)
{
  cerr << "setUVs Error" << endl;
}

if (fnMesh.assignUVs(polygonCounts, uvIDs, &setName) == MStatus::kFailure)
{
  cerr << "AssignUVs Error" << endl;
}

Output:

Current setName after getCurrentUVSetName:  
setUVs Error
AssignUVs Error

------------------------------------------------------------

As you can see no errors occured on Creation of the mesh -- and it seems it failed to create the UV set because the currentUVSetName is empty

[Anonymous · Accepted solution]

Apparently doing this:

MObject meshMObj = fnMeshCreator.create(uniquePositionsList->Count, mesh->Triangles->Count, mPointArray, polygonCounts, polygonConnects, meshTransformObj, &status);

if (status == MStatus::kFailure)
{
  cerr << "Mesh create error" << endl;
}

MFnMesh fnMesh(meshMObj);

breaks it.

Instead doing:

MFnMesh fnMesh;
fnMesh.create(uniquePositionsList->Count, mesh->Triangles->Count, mPointArray, polygonCounts, polygonConnects, meshTransformObj, &status);

seems to not have errors in the setting of UVs anymore