Rigify autoweight problem

Hello, I’ve been through the Rigify course from CGDive and my first attempt outside the supplied models failed. I’m trying to create a poseable drawing reference. Here is the blend file: https://www.dropbox.com/s/4m57ko1y731hpo2/proportions_rigged.v2.blend?dl=0

I created a fairly simple mesh. Created a basic human metarig. Rigify. Parented mesh to rig in object mode. The mesh doesn’t move when in pose mode. I go into weight paint mode and everything is blue.

If you parent with autoweights, you’ll see a small error message, “failed to find solution for one or more bones”. That means, autoweights didn’t take.

The first thing to do is to check normals and fix non-manifold areas of the mesh. You have issues with both. Enable “face orientation” in overlays to see your normal problems. Use “select non manifold” operation to find non manifold places so that you can fix them. Your mesh is too dense for me to enjoy figuring it out myself, but it looks like you’ve had some problems with doubled verts that got merged in some places but not others. That’s bad.

(Another source of autoweights problems is model scale. I like to make my models about 10-20 Blender units tall. It’s dumb, but it affects autoweights. 6 units tall may be pushing it. The “recommended” scale, with a character under 2 units, is terrible for autoweights.)

Note that autoweights don’t work well on multiple, disconnected meshes, like you have here. So even if you get autoweights working, it might be work how you want. Your best bet is to weight manually.

For your purposes, as a drawing reference, you might consider separating the object by loose parts (p->by loose parts in edit mode) and then parenting each object bone-relative (select object, shift select armature, enter pose mode, select appropriate bone, ctrl p -> bone relative.) At least, for some of the objects-- the spine wouldn’t be great for that.

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Thank you! I appreciate you taking the time to look at this. I’ll see if I can fix the problems you point out.

Hi @Edward_Allen . First I am happy you’re working through my course.
What @bandages said is spot on, IMHO.
In your case, the problem is most likely the fact that the model is made of many parts. Automatic weights fails often with these kinds of models. You can try Envelop Weights instead of Auto weights but the results are usually subpar.

The model itself has some issues. To fix a lot fo them you could do the following.
Go to edit mode, select all verts > Merge by distance.
After that press shift+N to fix the normals

For models like this it will be hard to avoid setting weights by hand. Which isn’t that hard… I have a playlist on weight painting that my help.

Thank you! I really appreciate all the work you put into the video series. Clear and excellent content!

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yeah i took a quick look at your file.
problem is less likely about rigify, weight. as you seem to know what you’re doing
and these steps are not that complicated.

you need to fix the head part.

the helmet “wires” shouldn’t be part of the body, as these are not body parts-
they dont stretch / bend etc.
things like this are in different mesh and you simply parent them to head bone later.

the head sphere itself seems intact but in fact scattered,
go into edit mode and try to move a face or vertex, they need to stay together.