Rigging a Human Mesh Made from Multiple Shapes (Automatic Weights)

Hi everyone,

I’m currently working on a very simple character and a few animations so that I have something to work with in Unreal, and am following along with a tutorial on rigging. This is my character:

As you can see, I’ve assembled it “artist dummy” style, using multiple spheres and cylinders instead of one “blob” mesh. Everything has been going totally fine, right up until it’s time to pair my rig with my mesh. I’ve trying to follow along with the steps in the tutorial, which are: Select Mesh -> Shift Select Rig -> Ctrl + P -> “With Automatic Weights.” At this step, it fails, and I get the message “Bone Heat Weighting: Failed to find solution for one or more bones.”

I’m not entirely sure why this is happening, but the only difference between me and the tutorial is that I’m using a multi-part mesh instead of a seamless one. Does this prevent me from using automatic weights at all, and if so, is there a workaround? Or would it be better to just redo the mesh completely as a seamless piece? Weight painting is something I’ll learn at some point, but I’m purely creating this character to use in a game engine and would like to keep things as simple as possible. Any input is appreciated!

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You can use separate meshes and not get deform if you use Ctrl-P > Bone. That will leave the meshes unweighted. Just parent each mesh to the appropriate bone.

I believe automatic weights requires the mesh to be a single connected mesh in which all faces enclose a volume. However, if you don’t want to modify the mesh, you can parent with empty groups and assign faces to each of those groups. Not sure about Unreal, but in Unity, you would not want to separate the meshes as it slows the rendering.

Thanks for the help everyone!