Windows 3D Builder doesn't seem to export colours when exporting projects as a .obj file?

Question

Hi,

I have made some 3D models in Windows 3D Builder and I have exported them as .obj files. The .mtl file saves as normal and is saved in the same location with the same name. When importing it into a stage lighting visualisation software, "Syncronorm Depence R3", the model imports, however, it shows up as a light grey colour and none of the colours assigned to the model in Windows 3D Builder seem to be exported. I have also tried importing the model into another software called "Blender" and the same thing happens. I have tried this with multiple projects and they are all doing the same thing.

Has anyone got any suggestions of how to fix this issue?

Many Thanks,

Kind Regards,

Max

Answer 1

The previous answers aren't wrong, per se, but they are incomplete. The official .obj file format doesn't included color information in the .obj file (it would normally be in the .mtl file). HOWEVER a lot of software, including 3D Builder, DOES include vertex coloring information right in the .obj file AND many software programs look for and support this non-standard but widely-used practice. But the info is usually stored as decimal RGB values ranging between 0 and 1, whereas Microsoft 3D Builder uses integers between 0 and 255, which other programs don't recognize and therefore ignore. I ran into this myself, and wrote a short python utility to map the value ranges to between 0 and 1. You can read more here: https://www.mcgurrin.info/robots/8123/ and can download the program from here: https://gist.github.com/ViennaMike/aa045d0ac17505b8229b5346bcfa80c5

I know that 3D Builder has been discontinued, but it can still be found and some folks (including myself) are still using it.

Answer 2

Hi, thank you for your reply. I have already done this, and the .obj and .mtl file have the same name and are in the same location. I'm not sure why it's still not exporting the colours?

Answer 3

Hello there,

When you export as an OBJ file, the colours are not stored within the model, only the separate pieces, the polygons that shape them, and which material covers which polygons. If you want to colour after exporting it you need an MTL (material) file named after the model's OBJ file. This holds all of the different materials and surface types.

When you export an OBJ from 3DBuilder it will also save an MTL file with it (if you don't just click cancel, anyway.) You just need to import this MTL file and assign it to the mesh.

Hope this resolves your Query !!

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