Common mistakes when rigging humanoid 3D models include poor joint placement, ignoring natural movement limits, and inaccurate weight painting.
Placing joints away from anatomical landmarks (like elbows or hips) breaks realistic motion—for example, a misplaced shoulder can make arm swings rigid.
Forgetting rotation constraints (e.g., limiting knee bend to prevent backward hyperextension) leads to unnatural poses.
Uneven weight painting (a joint affecting too much/little mesh) causes deformation issues like stretching or pinching, such as a knee warping the thigh.
For beginners, test rigs with basic movements (walking) early and use human motion references to catch issues before finalizing.