How to clean up an AI-generated 3D model in Blender

Before you start

Make a copy of the original file. Some of these steps cannot be undone once you save, and you may want to go back to the raw model to try again. Do the steps in order. Fixing scale after decimation, for example, can change how the decimation behaves.

1. Import and fix scale

Import the model: File › Import › glTF 2.0 for GLB, or the FBX or OBJ importer. See the Blender import guide for settings.

Check the dimensions in the sidebar (N). If a chair is 90 metres tall, scale it down. Then apply the transforms with Ctrl+A › All Transforms, so the scale is real geometry rather than an object setting that confuses modifiers and engines.

2. Merge duplicate vertices

Generated meshes often have vertices sitting on top of each other along seams. In Edit Mode, select all (A), then Mesh › Clean Up › Merge by Distance. Blender reports how many vertices it removed. Keep the distance small, so you do not collapse real detail.

3. Fix normals

Turn on Face Orientation in the viewport overlays. Blue faces point out and red faces point in. Select all and use Mesh › Normals › Recalculate Outside (Shift+N). Check again for red patches, which usually mean an inside-out region or an open hole.

4. Reduce the polygon count

Raw AI meshes are usually far denser than they need to be. There are two ways to fix that, depending on what the model is for:

• Decimate, for static props that will never deform. Add a Decimate modifier, lower the ratio until the silhouette starts to suffer, then go back up a little. It is fast and keeps the shape, but leaves messy triangles.
• Retopologise, for anything you will edit further, UV by hand, or animate. That means rebuilding the surface with clean quads, either by hand or with a remesher. It takes longer and gives you a mesh you can actually work with. See retopology.

5. Check the UVs

Decimation and remeshing can damage UVs. Open the UV Editor and look for overlapping or badly stretched islands. If you retopologised, you will need to unwrap the new mesh and bake the original textures onto it. See UV mapping.

6. Fix the textures

Look at the base colour texture on its own. AI texturing often paints in shadows and highlights, which look wrong under your scene's lighting. Paint them out in Texture Paint mode or an image editor. Check whether there are roughness, metallic and normal maps. If not, add them so the model reacts to light like the rest of your scene. See PBR materials.

7. Set the pivot and export

Put the origin where the object should rotate or rest. For most props that is the centre of the base: Object › Set Origin. Export in the format your destination wants, with transforms applied.

How much of this you can skip

Steps 4 and 5 take the longest, and they exist because most generators hand you a raw, dense mesh. Vi3W runs automatic retopology, from high-poly to low-poly, before you download, so the model arrives lighter and needs less of this work. Run the checks anyway. A quick look at scale, normals and textures is worth it on every model, whoever made it.