To sculpt blend shapes for VRChat 3D models, use software like Blender or ZBrush to create target shapes (e.g., smiles, blinks) from a clean base mesh, then link them to the avatar’s rig for VRChat SDK compatibility.
Blend shapes (shape keys) are base mesh deformations VRChat uses to animate avatars. Start with a finalized, clean-topology base—duplicate it to sculpt specific areas (e.g., pulling lip corners up) while matching the base’s topology to avoid artifacts.
Name shapes clearly (e.g., “Smile”) and align with VRChat’s parameters (like “Viseme” for mouth movements) so the SDK recognizes them.
For beginners, use Blender’s “Shape Keys” panel for simple edits, then test in the SDK. Avoid overcomplicating topology—clean meshes ensure smooth VRChat performance.