Automatic weights not working on the model I am making

Support Animation and Rigging
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1

Hello. I am making a model that is an orange robot. The issue comes up when trying to rig it. I’m using a meta-human rig because I want to get realistic proportions to make animations work well on it. However, even though I made the model accurate to the rig, applying the armature with automatic weights causes… THIS to happen.

weighting_error
weighting_error960×1000 200 KB

In case the image would not load, what happens is moving just about any bone moves way more of the body that it is supposed to, and barley moves the intended limb.

I have searched this problem up online, and here is what I have tried:
Making the mesh all continuous
Removing doubles
Merging vertices by distance
Adjusting the proportions of the avatar.

Here are the files I am working with. Just a .blend and a .png
orangebot.zip (544.3 KB)

2

Hello there!

The issue seems to be in the scale of the model (non-uniform and negative).
Object > Apply > Scale (Ctrl + A). Since the scale is negative this action will invert normals. Recalculate them in Edit Mode (Mesh > Normals or Alt + N).
After that auto-weight the object again.

PS. Also notice Merge Distance in Mirror mod will become too big for this mesh and needs adjustment.