What an emissive mask does in Roblox
A SurfaceAppearance can carry five maps: color, normal, roughness, metalness and an emissive mask. The mask is the odd one out. It is not a color image. It is one grayscale channel where black means no glow and white means full glow. Roblox adds that glow on top of the lighting and multiplies the result by the color map, then by EmissiveTint. EmissiveStrength scales the whole thing.
So the color of a glowing area is already in your texture. A cyan strip in the color map glows cyan. If you want a red light and a blue light on the same hat, paint them red and blue in the color map and keep both white in the mask. This is also why near-black areas barely glow: anything times black is still black. The check above warns you when that happens.
Uploading an RGB file as the mask does not give you colored glow. Roblox reads only the red channel, so a green or blue light in that file simply will not glow. This tool always exports a true 8-bit grayscale PNG.
How to make glowing UGC
- Build the mask here from the same texture you use as the ColorMap, so it lines up with your UVs.
- In Studio, import the mesh. For accessories, open the Accessory Fitting Tool and choose Generate MeshPart Accessory. The legacy option drops emissive.
- Add a SurfaceAppearance to the MeshPart and set ColorMap and EmissiveMaskContent to your uploaded images.
- Set EmissiveStrength between 0 and 40 and pick an EmissiveTint. If the mask slot is empty, the item is not classed as emissive even with strength set.
- Do not combine a TextureContent and a SurfaceAppearance on the same part, then Save to Roblox and submit.
At launch on September 2, 2026, Roblox charged 500 Robux to upload each emissive item and allowed one emissive upload per creator per day. Publishing advances and price floors were about five times the normal category values. Those terms come from the official announcement and may change, so check it before you plan a drop.
Roblox emissive limits
These are the numbers the check uses. Each one links to where Roblox published it. Coverage is the only rule without a hard number, so the tool treats it as a warning, never a fail.
| Rule | Limit | Source |
|---|---|---|
| Mask format | Grayscale. Only the red channel is read from RGB files. | DevForum |
| File type | PNG, JPG, TGA or BMP. 8-bit single channel is the spec. | Texture specs |
| EmissiveStrength, Marketplace | 0 to 40 | PBR textures |
| Largest texture, any use | 4096 x 4096 | Texture specs |
| Largest texture, Marketplace | 2048 x 2048 | Accessory specs |
| PBR budget, biggest items | 1024 x 1024 | Texture budget |
| Non-color maps, rigid accessories | 256 x 256 budget | Texture budget |
| Glow coverage | No number yet. Very large glowing areas are not allowed. | DevForum, Sept 4 2026 |
| Supported items | 3D accessories, layered clothing, bodies, heads, parts. Not 2D clothing. | PBR textures |
What makes a mask look good
Glow works best on small, deliberate details: visor slits, trim lines, runes, screens, the tips of horns. Lighting a whole item flattens its shape, and it is the pattern Roblox called out as disruptive. A few habits help:
- Feather by a pixel or two. Hard edges shimmer when Roblox streams a smaller mip of the texture.
- Use Mask brightness to dim secondary lights instead of making a second item. Gray in the mask glows less than white.
- Check the glow view at a few strengths. A value that looks right at 40 in a dark test place can be harsh in a bright game.
- Keep the mask the same size as the color map. They share UVs, and mismatched sizes make edges drift.
The rest of the material
The emissive mask covers glow only. For the normal, roughness and metalness maps of the same texture, run it through the PBR generator, or read the Roblox PBR guide for how SurfaceAppearance reads each one. The normal map generator and roughness map generator pages explain those channels in more depth.