Common mistakes when animating blend shape 3D models include overusing extreme shape values, neglecting smooth interpolation between shapes, and ignoring real-world muscle or form logic.
Overusing extremes makes movements look exaggerated (e.g., a character’s smile stretching too wide). Poor interpolation causes jerky transitions instead of natural blends. Ignoring muscle logic breaks realism (like moving lips without lifting cheeks).
If you’re new, start with small adjustments and reference real expressions (e.g., using a mirror) to avoid these issues.