Roblox 3D models: how they work, where they come from, and how to make your own

Two kinds of 3D model in Roblox

Every visible object in a Roblox experience is built from one of two things.

• Parts are the primitives Studio gives you: blocks, spheres, cylinders and wedges. You place, scale and colour them inside Studio, and you can combine them into unions. Classic Roblox building is all Parts.
• MeshParts are custom shapes made somewhere else, in Blender, Maya or an AI generator, and imported into Studio. A mesh can be any shape: a curved sword, a stylised tree, a character's helmet.

Most games that look polished use both. Parts are quick for floors, walls and blockouts. MeshParts carry the detail, such as props, vegetation, vehicles, weapons and decorations.

The rules a mesh has to follow

Roblox's general mesh specifications set the limits every imported model must meet:

• 20,000 triangles per mesh at most. Avatar items have stricter budgets: rigid accessories, for example, are capped at 4,000. More in the Roblox triangle limit.
• Watertight geometry with some thickness. No holes, no zero-thickness planes, quads where possible.
• One material per mesh. A mesh takes one texture set: a single colour map, or a set of PBR maps through a SurfaceAppearance. See PBR textures in Roblox.
• Supported files: .fbx, .obj and .gltf/.glb, imported through Studio's Importer. The step-by-step is in how to import 3D models into Roblox Studio.

Size is measured in studs, and one stud is 28 cm according to Roblox's units page. If a model arrives giant or tiny, the studs to metres guide explains why.

Three ways to get a 3D model

1. The Creator Store

Studio's Toolbox gives you thousands of free and paid models. It is the quickest route, but the same assets show up in many other games, styles rarely match, and some free models hide malicious scripts. Roblox 3D assets covers how to vet them.

2. Model it yourself

Blender is free and Roblox documents its export settings in detail. You get complete control, at the cost of time and skill. If you already model, Blender to Roblox Studio lists the settings that avoid most import problems.

3. Generate it with AI

AI generators turn a prompt, a photo or a sketch into a textured mesh. Roblox has its own (Assistant's mesh generation, built on Cube), and external tools such as Vi3W export files you import yourself. The overview is in Roblox 3D AI, and the practical workflow is in how to make Roblox models with AI.

What makes a model "good" for Roblox

A good Roblox model is light, not just good-looking. Roblox runs on phones, and each mesh's triangles, textures and collision shape add to the load. A model that looks fine in Blender at 80,000 triangles might not import at all, and one at 18,000 imports but costs more than it needs to. Aim for:

• a triangle count that suits how close players get to the model (low-poly models for Roblox);
• texture sizes that match the object's size in studs;
• a simple collision shape (optimise Roblox meshes).

Make a model for your game

If the Creator Store doesn't have what you need and modelling it would take an afternoon, generate it. In Vi3W you describe the object, upload a photo or draw it, and get a textured mesh with automatic retopology to a low-poly version. You can rotate it in the browser and export GLB, FBX or OBJ for Studio's Importer. Vi3W makes static meshes, so animated characters still need rigging in Blender or Studio. Try it free in Vi3W.