Trying to use a rigify basic human rig, on a simple bi pedal model resulting in random movement of unrelated body parts?

Question

I'm new to blender and followed tutorials to make a basic bipedal model. I'm now trying to follow different Youtube videos to rig it using rigify and automatic weights. For the purpose of using the model as an initial test for a game I'm programming. However, when I put the automatic weights on random parts of the body move as well. I try removing the paint for them but they still move and the paint doesn't consistently come on.

Is there any suggestions for what I should try doing or whats going wrong(Thanks in Advance)?

My current Blender workspace

Answer 1

Beside the mirror as mention in josh sanfelici's answer, your mesh is has a more few common issues:

• duplicated vertices. Remove them in Edit mode, select everything with A, then press M and choose Merge By Distance (B)
• flipped normals. The mesh is inside out and that causes weighting problems and bad deformations. You can check this with the Face Orientation overlay, and then do a Recalculate Outside or simple Flip as described here: How to make all faces flip to the right/consistent direction?

Additionally,

• the mesh topology is not ideal for animation. I don't know which tutorials you have consulted but I recommend one for animation and game design like Easy Low Poly Character Modeling in Blender 2.9x or Modeling for Animation (series), Grant Abbitt and Royal Skies LLC have a lot of videos related to Blender and Unity.

• the meta rig is used for the bone layout to match the mesh. Usually, you don't bind it to the mesh but generate the final rig from it. This is done by the button Generate Rig. The mesh is then bound to the generated rig.

Answer 2

In Object mode select the character, go to modifier properties, hover the mouse over the mirror modifier and press Ctrl A, to freeze the mirroring into the mesh, then parent to the armature.