Common mistakes when animating armature 3D models include poor weight painting (unnatural mesh deformation), overusing/misplacing keyframes (rigid or jumpy motion), and neglecting inverse kinematics (IK) constraints (unrealistic joint bends).
Poor weight painting means vertices aren’t properly assigned to bones, so limbs stretch or bulge. Too many keyframes make animations robotic; missing ones create sudden gaps. Ignoring IK can make elbows bend backward instead of following natural paths.
Fix mesh issues by refining weight painting with soft selection; for rigid motion, simplify keyframes and add easing.