Adding New Uv Sets Inside A Node

[asterx]

Hi,

I'm writing a mesh loader node which should support uvs. My problem is that I can not add a new uv set inside my node.

I use the following "workflow" for uvs.

step 1
// geometry created from file, u & v arrays added
fMesh.create(numVertices,numPolygons,vertexArray,polygonCounts,polygonConnects,uArray,vArray,newMeshData,&status);

// mesh is set to the output
meshHandle.set(newMeshData);

step 2
// get back output mesh
MObject mesh = meshHandle.asMesh();
MFnMesh fMesh(mesh);

step 3
// create empty uv sets in a loop based on the number of the uv sets in file
fMesh.createUVSet(uvSet);

step 4
// assign uvs
fMesh.assignUVs(..,..,&uvSet);

So this is the base of my uv reader, step 3 is failed.

The problem should be something like this (documented in the API):
"This operation will only work when the MFnMesh refers to a shape."

How should I add multiple uv sets with uvs inside my loader node?

Thanks,
David

[pissed]

It took me a bit to figure this one out as well here's what I do in my importer:

create the uv set

CODE
meshNode.createUVSet( uvsetname );

name it
CODE
meshNode.setCurrentUVSetName( uvsetname );

set the UVs
CODE
meshNode.setUVs( uArray, vArray, &uvsetname );

Assign the UV set
CODE
meshNode.assignUVs( faceVertexCounts, UVIds, &uvsetname );

I should add, meshNode is an MFnMesh applied to the mesh shape node I created. I am actually setting multiple UV sets in a loop. In my code uvsetname is an MString array and this all happens in a loop.

[asterx]

Thanks, your solution seems to be similar.

"applied to the mesh shape node I created."

But in my code createUvSet(uvsetname) is failed. Because it is not applied to the mesh shape, I think.
What does it mean that an mfnmesh is applied to the shape in the code? My mfnmesh is set as a mesh output in my node, that seems to be not enough for uv set creation. (In maya I create a mesh node and connect this output to inMesh using MEL.)

Thanks
David

QUOTE(pissed @ 08/15/07, 07:33 PM) [snapback]271619[/snapback]
It took me a bit to figure this one out as well here's what I do in my importer:

create the uv set
CODE
meshNode.createUVSet( uvsetname );

name it
CODE
meshNode.setCurrentUVSetName( uvsetname );

set the UVs
CODE
meshNode.setUVs( uArray, vArray, &uvsetname );

Assign the UV set
CODE
meshNode.assignUVs( faceVertexCounts, UVIds, &uvsetname );

I should add, meshNode is an MFnMesh applied to the mesh shape node I created. I am actually setting multiple UV sets in a loop. In my code uvsetname is an MString array and this all happens in a loop.

[pissed]

Here's how I build the mesh

CODE
//Build the mesh
MFnMesh fn;
MObject obj = fn.create(  nPoints, nPrims, vertices, faceVertexCounts, faceVertexOrder, MObject::kNullObj, &status );
McheckErr(status,"MFnMesh::create() failed!");

MFnDagNode dagNode( obj, &status );
McheckErr(status,"MFnDagNode failed!");

dagNode.setName( nodeName, &status );
McheckErr(status,"MFnDagNode::setName() failed!");

MObject meshObj = dagNode.child(0, &status);
McheckErr(status,"MFnDagNode::child() failed!");

MFnMesh meshNode( meshObj, &status );
McheckErr(status,"MFnMesh failed!");

[asterx]

It works but my importer should also read file sequence, so this obj = mesh.create() and the others should be called multiple times. Your solution always creates a new shape node but i would like to update the same node (only update the geometry content). Any ideas?

[asterx]

I connect my geometry loader node to a mesh node. This code try to add uv sets to the node I connect my loader node to.
Number of uv sets are 1 after adding 3 uv maps.. The meshNode should be the mesh in the DAG (number of polygons, fullpathname etc are correct but I can not add uv sets..

[codebox]
if(plug==outMesh) {
MPlugArray plugArray;
plug.connectedTo(plugArray, 0, 1, &stat);
MObject meshNode = plugArray[0].node();

MFnDagNode dagNode(meshNode,&stat);
dagNode.setName("geoModel");
MObject shapeNode = dagNode.parent(0, &stat);
MFnDagNode dagNode2(shapeNode,&stat);
dagNode2.setName("geoModelShape");

MFnMesh mesh(meshNode, &stat);

mesh.createUVSet(MString("uv1"));
mesh.createUVSet(MString("uv2"));
mesh.createUVSet(MString("uv3"));

printf("%d ",mesh.numUVSets());
[/codebox]

[pissed]

I also read sequences, however I do that with a deformer node. The importer command reads a file and creates a mesh node, the deformer only reads the mesh points in object space, a world trasform matrix, and normals (you can make it read whatever else you need as well, say animated UV sets). The point is, you don't want to read in an entire mesh and rebuild it every frame, that'd be slow. You only what to read in the data that changes and apply it to the existing mesh. You can wrap up the importer command and deformer node with a MEL script with an interface or whatever to make it easy to work with.

If you try to read in and rebuild the entire mesh at every frame, you are going to find it very difficult to work with large meshes or meshes that have a lot of attributes on them. I have meshes that have like 30K+ primitives and mutliple UV and color sets as well as vertex attributes. Some of these meshes take seconds to read and build in Maya, which is completely unacceptable. Using a separate deformer node that reads only the neccessary info and applies it to a loaded mesh, I can scrub large data sets in real time.

For the UVs, all I can tell you is that with multiple UV sets, I create and set them one at a time and it works fine. I create a set, then setCurrentUVSetName to make certain my new set is the current set, I setUVs, and finally assignUVs, then move on to the next UV set. I don't see why trying to just create a bunch of empty sets one after the other would be an issue, but there's a lot of things about Maya and it's API that don't make a damn bit of sense to me.