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Hi,
I have a maya model attached in this post that I am trying to export.
I have my own rigged mesh representation.
In that, I export the
- bind pose world matrices for each joint (from the bindPose attribute on a joint node)
- the bind pose world vertex positions of the mesh
- the joint world matrices of each joint (using the inclusiveMatrix()) for each animation frame (all keyed on translation/rotation/scale)
- and the respective weights and joint indices for each vertex
I then perform skinning for frame i by doing:
skinned world vertex = (0, 0, 0)
skinned world vertex += (bind pose world vertex position) * (bindPose world matric inverse for joint k) * (world matrix for joint k on frame i) * (weight for joint k), for all joint k that influences that vertex
this approach works for some models but fails for the one I have (it just have one mesh with a hierarchy of joints)
I verify the approach by writing a command in maya that takes in a vertex idx and a frame idx and it outputs the world space bind pose points and world space skinned points by directly querying the maya mesh
this is the output from the command
// Selected mesh: |Ganfaul|GanfaulShape //
// GanfaulShape is a riggedMesh, skin cluster name: skinCluster1 //
// Checking mesh: GanfaulShape, vertexID: 4685, frameIdx: 3 //
// Bind Pose Local Space Point: -1.702918, 182.58876, 8.60685 //
// Bind Pose World Space Point: -1.702918, 182.58876, 8.60685 //
// Calculated Bind Pose World Space Point: -1.702918, 182.58876, 8.60685 //
// Num joint influence : 65 //
// Num weights for vertex: 511225 //
// Num joints for vertex : 65 //
// Valid joint idx: 59, name: Head, weight: 1, bind pose list name: Head //
// Frame Local Space Point: -3.06953, 175.204819, 7.018704 //
// Frame World Space Point: -3.06953, 175.204819, 7.018704 //
// Calculated Frame World Space Point: 4.036224, 153.692543, 25.453149 //
here is the code for the command
MObject skinClusterObj;
MObject skinnedMeshObj = skinnedMeshDag.node();
if (!MayaHelper::isMeshRigged(skinnedMeshObj, skinClusterObj))
{
MayaLog::OutputInfo(" TestCmd, selected mesh is not rigged");
return;
}
MStatus stats = MS::kSuccess;
MayaHelper::animControlGoToFirstFrame();
MayaHelper::setAllJointToBindPose();
MFnMesh meshFn(skinnedMeshDag);
MayaLog::OutputInfo(MString(" Checking mesh: ") + meshFn.name() + MString(", vertexID: ") + vertexId + MString(", frameIdx: ") + frameIdx);
MPoint bindPoseLocalSpacePoint;
MPoint bindPoseWorldSpacePoint;
stats = meshFn.getPoint(vertexId, bindPoseLocalSpacePoint, MSpace::kObject);
if (stats != MS::kSuccess)
{
MayaLog::OutputError(" Error getting bind pose local space point");
return;
}
stats = meshFn.getPoint(vertexId, bindPoseWorldSpacePoint, MSpace::kWorld);
if (stats != MS::kSuccess)
{
MayaLog::OutputError(" Error getting bind pose world space point");
return;
}
MDagPath skinnedMeshParentDag = skinnedMeshDag;
skinnedMeshParentDag.pop();
const MPoint bindPoseWorldCalculated = bindPoseLocalSpacePoint * skinnedMeshParentDag.inclusiveMatrix();
MayaHelper::printMPoint(MString(" Bind Pose Local Space Point: "), bindPoseLocalSpacePoint);
MayaHelper::printMPoint(MString(" Bind Pose World Space Point: "), bindPoseWorldSpacePoint);
MayaHelper::printMPoint(MString(" Calculated Bind Pose World Space Point: "), bindPoseWorldCalculated);
MFnSkinCluster skinClusterFn(skinClusterObj);
MDagPathArray jointDags;
skinClusterFn.influenceObjects(jointDags);
const unsigned int numJoints = jointDags.length();
// get bind pose world transforms
struct JointBindPoseInfo
{
std::string jointName;
MTransformationMatrix bindPoseWorldTransMat;
JointBindPoseInfo() :
jointName(""),
bindPoseWorldTransMat(MTransformationMatrix::identity),
{}
};
std::vector<JointBindPoseInfo> jointsBindPoseWorld(numJoints);
for (unsigned int i = 0; i < numJoints; ++i)
{
const MString jointName = jointDags[i].partialPathName();
MFnIkJoint jointFn(jointDags[i]);
// get the world bind pose matrix for this bone
// and store it in the bone desc
MPlug bindPosePlug = jointFn.findPlug(c_jointNodeBindPoseAttrName);
const MFnMatrixData bindPoseMatrixDataFn(bindPosePlug.asMObject());
// export bind pose world
const MMatrix bindPoseMatWorld = bindPoseMatrixDataFn.matrix();
jointsBindPoseWorld[i].jointName = jointName.asChar();
jointsBindPoseWorld[i].bindPoseWorldTransMat = bindPoseMatWorld;
MString transformName = jointName + MString("_bindPoseWorld");
}
MayaHelper::animControlGoToFrame(frameIdx);
MPoint frameWorldCalculated(0, 0, 0);
MPoint frameLocalSpacePoint;
MPoint frameWorldSpacePoint;
stats = meshFn.getPoint(vertexId, frameLocalSpacePoint, MSpace::kObject);
if (stats != MS::kSuccess)
{
MayaLog::OutputError(" Error getting frame local space point");
return;
}
stats = meshFn.getPoint(vertexId, frameWorldSpacePoint, MSpace::kWorld);
if (stats != MS::kSuccess)
{
MayaLog::OutputError(" Error getting frame world space point");
return;
}
MDoubleArray weights;
{
MIntArray elementArray;
elementArray.append(vertexId);
MFnSingleIndexedComponent vertices;
vertices.addElements(elementArray);
MObject vertComponents = vertices.create(MFn::kMeshVertComponent);
// numJointInfluences will always be number of bones in the skeleton even if they have weight of 0
// so weights will be numVerts * numJointInfluences big
// however, joints not part of influence list are not counted
unsigned int numJointInfluences = 0;
skinClusterFn.getWeights(skinnedMeshDag, vertComponents, weights, numJointInfluences);
const unsigned int numWeights = weights.length();
MayaLog::OutputInfo(MString(" Num joint influence : ") + numJointInfluences);
MayaLog::OutputInfo(MString(" Num weights for vertex: ") + numWeights);
MayaLog::OutputInfo(MString(" Num joints for vertex : ") + numJoints);
std::vector<double> vertWeights(numJointInfluences, 0.0);
for (unsigned int j = 0; j < numJointInfluences; ++j)
{
const double& weight = weights[vertexId * numJointInfluences + j];
vertWeights[j] = weight;
}
struct JointWeightInfo
{
MString jointName;
MDagPath jointDag;
double weight;
JointWeightInfo() :
jointName(""),
jointDag(),
weight(0.0)
{}
};
std::vector<JointWeightInfo> validJointAndWeights;
for (unsigned int i = 0; i < numJointInfluences; ++i)
{
if (vertWeights[i] > 0.0)
{
JointWeightInfo weightInfo;
weightInfo.jointName = jointDags[i].partialPathName();
weightInfo.jointDag = jointDags[i];
weightInfo.weight = vertWeights[i];
validJointAndWeights.emplace_back(weightInfo);
MayaLog::OutputInfo(MString(" Valid joint idx: ") + i + MString(", name: ") + jointDags[i].partialPathName() + MString(", weight: ") + vertWeights[i] + MString(", bind pose list name: ") + jointsBindPoseWorld[i].jointName.c_str());
frameWorldCalculated += vertWeights[i] * (bindPoseWorldCalculated *
jointsBindPoseWorld[i].bindPoseWorldTransMat.asMatrixInverse() *
jointDags[i].inclusiveMatrix());
}
}
}
MayaHelper::printMPoint(MString(" Frame Local Space Point: "), frameLocalSpacePoint);
MayaHelper::printMPoint(MString(" Frame World Space Point: "), frameWorldSpacePoint);
MayaHelper::printMPoint(MString(" Calculated Frame World Space Point: "), frameWorldCalculated);
MayaHelper::animControlGoToFirstFrame();
MayaHelper::setAllJointToBindPose();Is there any transform that I could have possibly not gotten from Maya to perform the skinning? It works well for most rigged meshs I created myself but for this model it doesn't. I would appreciate any help on this thanks!
Solved! Go to Solution.
