topic Re: Paint Blend Shape Weights Tool via Python/MEL? in Maya Programming Forum

Paint Blend Shape Weights Tool via Python/MEL?

jmalaska — Sun, 20 Sep 2020 02:27:06 GMT

Trying to do some very targeted blendshape painting. What I'd like to be able to do is select a series of vertices with soft selection, and have that selection be my "painted weights". I don't really want to have to go through manually painting weights.

Are there Python commands to help with this?

I can't dig to find out what the Paint Blendshape Weights tool is doing. The Node Graph doesn't show any intermediary that would hold this data.

https://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2020/ENU/Maya-CharacterAnimation/files/GUID-E49E9C30-D03A-456D-B7E8-FF99DA8C11E4-htm.html

Re: Paint Blend Shape Weights Tool via Python/MEL?

lee.dunham — Sun, 20 Sep 2020 03:14:52 GMT

So its certainly possible, although it will depend on how comfortable you are with python.

First off, you need to get the components and "weighting" from the soft selection;

https://github.com/ldunham1/maya_utilities/blob/master/ld_soft_cluster.py

def _get_soft_selection(): """ Return the current soft selection components and normalised influence weights. :return: List of components and matching weights. :rtype: list(str), list(float) """ # Grab the soft selection selection = om.MSelectionList() soft_sel = om.MRichSelection() om.MGlobal.getRichSelection(soft_sel) soft_sel.getSelection(selection) dag_path = om.MDagPath() component = om.MObject() # Filter Defeats the purpose of the else statement iter_sel = om.MItSelectionList(selection, om.MFn.kMeshVertComponent) elements, weights = [], [] while not iter_sel.isDone(): iter_sel.getDagPath(dag_path, component) # Grab the parent of the shape node dag_path.pop() node = dag_path.fullPathName() fn_comp = om.MFnSingleIndexedComponent(component) vtx_str = node + '.vtx[{}]' for i in range(fn_comp.elementCount()): elements.append(vtx_str.format(fn_comp.element(i))) weights.append(fn_comp.weight(i).influence() if fn_comp.hasWeights() else 1.0) iter_sel.next() return elements, weights

Then, modify the blendshape weights using the component index and soft selection weight - these two posts should help you out there.

https://yantor3d.wordpress.com/2017/09/16/inside-the-node-blendshape/

https://soup-dev.websitetoolbox.com/post/setting-blendshape-weights-through-maya-api-7116714?pid=1284620311

Hint: You're modify this to affect the blendshape base weights, although you can also access target specific weights too;

blendshape.inputTarget[0].baseWeights

Hope this helps!

Re: Paint Blend Shape Weights Tool via Python/MEL?

jmalaska — Sat, 05 Dec 2020 04:09:45 GMT

Lee, this is wicked awesome. Thank you for dropping your knowledge! Exactly what I was looking for. Cheers!

Re: Paint Blend Shape Weights Tool via Python/MEL?

lee.dunham — Sat, 05 Dec 2020 04:22:17 GMT

Not a problem, glad it's helpful 🙂