A material change is a scope question first
Before touching a colour, decide which parts the new material applies to. “Make it walnut” almost never means the whole model — it means the frame, and not the upholstery; or the legs, and not the stretchers. If parts share one material, changing it changes all of them at once, which is either exactly what you want or a surprise.
- One material per part is the clearest arrangement, and the easiest to change later.
- One material shared by a repeated group keeps sixty columns identical by construction.
- One material for the whole model is the arrangement that makes every future change a selection problem.
What the PBR values actually do
| Value | Range | What it controls |
|---|---|---|
| Base colour | sRGB colour | The diffuse colour for non-metals; for metals it tints the reflection instead. |
| Metallic | 0 or 1, rarely between | Whether the surface is a metal. Values in between are for transitions like worn paint, not for “a bit shiny”. |
| Roughness | 0–1 | How wide the highlight spreads. 0.05 is polished glass, 0.3 brushed steel, 0.6 satin wood, 0.9 raw concrete. |
| Clearcoat | 0–1 | A thin glossy layer over the base — car paint, varnished timber, gelcoat on a hull. |
| Sheen | 0–1 | The soft rim brightness of cloth. The reason fabric looks like plastic without it. |
Most “wrong looking” material swaps are a metalness of 1 on something that is not metal, or a roughness left at the default while the reference is satin. Fix those two before adjusting the colour.
If it still looks wrong, it is probably the lighting
A PBR material has nothing to reflect in an empty scene, so polished surfaces render as flat colour and the change you made appears to do nothing. Give the scene something to be reflected — an environment, or a few area lights — before judging a material.
- Metals are almost entirely reflection. With no environment, they read as dark grey.
- A single point light gives one specular dot; a broad area light gives the long highlight that reads as a real surface.
- Judge roughness with a bright strip light in the scene, where you can see the highlight stretch and blur.
Keeping materials through an export
- 01Use the standard PBR inputsBase colour, metallic, roughness, normal. Exporters map these directly; a hand-built shader graph usually exports as a flat colour or not at all.
- 02Name the materials“Walnut” survives review; “Material.004” does not tell a reviewer or a future you anything.
- 03Pack or reference textures deliberatelyGLB embeds images in the file. glTF keeps them beside it. Choose knowingly, and check the file size afterwards.
- 04Re-import and lookOpen your own export. Materials that silently reverted to a default show up immediately.
Material changes in Refora
Refora applies supported material presets to selected parts, and a GLB export carries geometry, part names, materials and embedded preset images through a round trip. Applying your own uploaded texture image and choosing an arbitrary colour independent of a preset are both in testing rather than shipped, and the limitations page says so plainly — the presets are what you can rely on today.
Questions
- How do I change the colour of one part of a 3D model?
- Give that part its own material rather than editing a material shared with other parts, then change its base colour. If the part currently shares a material, duplicate the material first and assign the copy to the part.
- Why does my metal material look black?
- Metals render almost entirely from what they reflect. With no environment or area lights in the scene there is nothing to reflect, so the surface goes dark. Add an environment before judging it.
- Should metallic ever be set between 0 and 1?
- Rarely. Metallic is a description of what a substance is, not how shiny it looks. Use roughness for shininess and reserve intermediate metallic values for transitions like worn paint over metal.
- Do materials survive a GLB export?
- Standard PBR inputs — base colour, metallic, roughness, normal — export reliably. Custom shader graphs generally do not; they collapse to a flat colour. Re-import your export to check before relying on it.