Rigging models that move cleanly

Decide what moves before you join anything

Anything that moves on its own (a jaw, a limb, a blade arm, a wheel) must be either:

• a separate rigid piece with its own pivot, connected by a Motor6D; or
• a skinned bone that deforms the mesh around it.

Make that call before joining geometry. Parts that never move apart get joined into one mesh; parts that do must stay separate. Separating them afterwards means rebuilding.

Rigid pieces suit mechanical and blocky things: robots, vehicles, stud-style creatures, anything Roblox-avatar-like. Bones suit organic bending: tails, tentacles, cloth, soft creatures.

Every joint must look attached

Where two parts meet, one must enter the other with its cross-section unchanged. A flat end resting against a curved surface reads as unattached the moment it moves. Push it in so the seam is hidden at every angle the joint can reach.

Curves bend at joints

Organic forms (trunks, tails, necks) are chains of segments: each segment starts buried about 0.3 studs into the end of the previous one and turns a consistent angle further. The arc then reads as continuous, and it can be posed segment by segment later.

Triangle budgets

Report the count, and never decimate without comparing before and after.

Vertex colour first

For stylised Roblox models, vertex colour is the default material: it survives export to GLB and into EditableMesh with no texture upload. Use image textures only when the reference needs detail vertex colour can't carry.

Check the exported file, not the scene

The final check is on the exported GLB, not the Blender scene. Exports can flip normals, drop modifiers or change what you see.

Partly adapted from blender-kiln (github.com/elithril/blender-kiln, MIT licence).