Merge Materials

Why draw calls are the number that matters

A modern GPU shrugs at triangles and chokes on state changes. Every material on every mesh is a separate draw call — a round trip of state setup that costs the same whether the mesh has 300 triangles or 300,000. A scene prop assembled from 40 parts with 12 materials spends more frame time being dispatched than being drawn.

Merging does the thing engines wish you had done in the DCC: one mesh, one material, one call. The triangle count does not change at all — this is not decimation — but the dispatch overhead collapses.

What actually happens to the textures

Every material slot that exists anywhere on the model — base colour, normal, roughness, metalness, occlusion, emissive — is re-baked into one shared atlas laid out fresh for the whole model. Materials that carried a flat colour or a scalar instead of a texture are baked in too: the colour becomes texels, a tint on a texture is multiplied into it, a roughness slider becomes a grey value in the shared roughness map.

That last part is the difference between this and a naive atlas packer: nothing that lived in material settings is lost, because everything is moved into texel space before the materials are unified.

What does not survive, said plainly

A merge is for static things — environment props, product models, scene dressing. Skeletons, skin weights and animation clips do not survive: forty parts that became one mesh can no longer move relative to each other. Merge the environment, not the character.

Per-part visibility is gone for the same reason — you can no longer hide the lid of a merged chest. And if opaque and transparent parts are merged together, the single material has to be transparent, which can sort oddly. When that happens the page says so.

When NOT to use it

If parts of the model repeat — ten identical chairs — instancing beats merging: one draw call per unique mesh with the copies drawn by the GPU. Merging the ten chairs bakes ten copies of the same texels into the atlas. Merge unique clutter; instance repetition.

How to use it

1. Drop your model into the box above.
2. Pick an atlas size, or let Auto match the source textures.
3. Press Merge materials and compare the draw-call count before and after.
4. Download the GLB — one mesh, one material, one draw call.

Questions

How do I reduce draw calls in my 3D model?

Combine meshes that share a material, and combine materials so more meshes can share one. This page does both at once: it re-bakes every texture into one shared atlas so that every mesh CAN share one material, then merges the meshes. The result renders in a single draw call.

Does the model lose quality?

The geometry is untouched — same triangles, same silhouette. The textures are resampled once into the shared atlas, which at the Auto resolution means roughly the same texel density as the source. A model with many large textures squeezed into one 2048 atlas will soften; pick 4096 if that matters.

Why did my animated character come back rigid?

Because a merge produces one static mesh — skin weights and clips have nowhere to live when the parts they moved no longer exist. The tool says this in the result notes rather than failing silently. For characters, reduce polygons or bake maps instead; merge the scenery.

Is my model uploaded?

No. The unwrap, the re-bake and the merge all run in the browser tab on your machine. Nothing leaves it, and there is no file size limit beyond what the tab can hold.

The other tools

• Batch processing — Run any Rig Bake tool over a whole folder of models and get one zip back.
• Reduce polygons — Cut the triangle count of a GLB, GLTF, FBX, OBJ, DAE, STL, PLY, VOX or VRM — or a zipped model folder — and keep the textures. Runs in your browser, no file size limit, nothing uploaded.
• Quad remesh — Rebuild any mesh as clean quads with real edge flow, in your browser — with the UVs and textures rebuilt onto the new surface too. Reads GLB, GLTF, FBX, OBJ, DAE, STL, PLY, VOX and VRM, with no file size limit.
• Bake a normal map — Bake high-poly detail into a normal map (and ambient occlusion) for a light version of the model — the xNormal workflow, in your browser. Drop one heavy model, or add your own low-poly and the maps bake onto its UVs. No upload, no account, no file size limit.
• Compress GLB — Name the file size you need and get it. Drop a GLB, GLTF, FBX, OBJ, DAE, STL, PLY, VOX or VRM — or a zipped model folder — and the page works down a list: dead weight first, then the mesh bytes, then the textures, and only then the triangles. In your browser, no file size limit.
• FBX to GLB — Convert an FBX — Mixamo, Blender, an AI generator — into a GLB, with the centimetre scale fixed on the way through. Any size, in your browser, nothing uploaded.
• Check a 3D model for problems — The Model doctor: find what is wrong with a model before it wastes your afternoon — wrong scale, broken bind pose, inverted normals, overlapping UVs, holes. Reads GLB, GLTF, FBX, OBJ, DAE, STL, PLY, VOX and VRM, any size, in your browser.
• Repair a 3D model — Weld split vertices, drop degenerate faces and stray islands, fill holes, flip inverted normals. GLB, GLTF, FBX, OBJ, DAE, STL, PLY, VOX or VRM — any size, in your browser, nothing uploaded.
• Pixel art from 3D — Drop an animated model, get a pixel-art spritesheet. The palette, the dither and the direction set are already chosen — fine-tuning lives in the editor.
• GLB to STL — Convert a 3D model to a printable STL — scaled to real millimetres, turned Z-up, and told plainly whether it is watertight. GLB, GLTF, FBX, OBJ, DAE, PLY, VOX or VRM in, any size, in your browser.
• OBJ to GLB — Convert an .obj into a GLB that engines and browsers read. Geometry and UVs travel; OBJ has nothing else to carry. Any size, in your browser, nothing uploaded.
• GLB to USDZ — Convert a 3D model to USDZ for AR Quick Look on iPhone and iPad — textures included. Any size, in your browser, nothing uploaded.
• LOD Generator — Turn one model into a chain of LOD meshes — each level a measured step down, zipped together with per-level stats. In your browser, nothing uploaded.
• Everything else Rig Bake does — rigging, retargeting, spritesheets, VFX.