My obj file and mtl are in the same folder and named the same name. I import obj and don’t get any pop up about using the mtl to autopaint?
I looked to see if BS would import an .mtl file. There is no option for that file format.
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Yeah, so how do we do it? It’s listed as a feature in the new update.
Oh sorry. I have not updated yet. 
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Perhaps try watching the video Google found for me.
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Not super helpful. Do you have an obj and mtl that work in Bambu Studio that I can try? Or a link to that geometry node setup for Blender shown in the video?.
Am using Bambu studio 1.9.3.50
I have several different obj and mtl exported from Blender that display colors properly in every other program I’ve tried, for example, reimporting into Blender, of course, 3D Viewer, and Print 3D all work fine. I tried with several different files with no success. It pops right up with little delay in Bambu Studio with no color, unlike most of the videos I’ve seen, where it takes a little while and then shows a color dialog. I tried everything and watched all the youtube videos. It just doesn’t work. what is the trick?
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I am in the same boat trying to do the same thing. I followed the video steps and I have an obj and mtl file but i lose the coloring and I’m not given the window to select colors.
I discovered that the obj file needs to have vertex color for Bambu Studio to use the color So you don’t need the .mtl file or texture files at all. The color needs to be “baked” into the obj as vertex color (youtube has videos showing how)… You need to apply your color to the vertices in Blender. The obj file needs to have rgb values as the last three numbers in the vertex data like this (viewed in notepad++)
o Cube
v -25.000000 -25.000000 25.000000 0.0633 0.9793 0.2322
v -25.000000 25.000000 25.000000 0.9666 0.0000 0.4926
Now Bambu studio accepts the colors from Blender.
…
Here are some steps to bake textures to vertex colors in Blender:
- Unwrap the model
- Load the image to bake into the model’s Vertex Colors in the UV/Image-editor
- Enter Vertex Paint mode
- Open the Toolshelf T and click UV Texture to VCols
…
I may be missing something, but I couldn’t get the mtl file to work and as soon as I tried vertex color it worked. So until I learn otherwise, I will assume mtl files are not supported and will use vertex color. I think it is important to understand what is going on to get decent results, there is a big difference with vertex color.
Limitations of Blender Vertex Colors
- Resolution Dependency:
- Vertex Color Limitation: Vertex colors are stored directly on the vertices of a mesh. This means that the color information can only change at the vertices. If your mesh has a low resolution (few vertices), the color transitions will be less smooth, and you won’t have fine control over the color details.
- Mesh Density Requirement: To achieve smooth and detailed color gradients or patterns, you need a high-resolution mesh with many vertices. This increases the polygon count and can make the model more complex and heavier to process.
- Lack of Detail:
- Limited Detail: Because vertex colors depend on the vertices’ placement, achieving fine details and intricate patterns is challenging. This is in contrast to UV texture mapping, where you can paint or apply high-resolution textures independently of the mesh’s resolution.
- Editing Complexity:
- Complex Edits: Making detailed adjustments to vertex colors can be more complicated than editing a 2D texture. Precise color changes might require adding more vertices or manually tweaking vertex positions and colors.
Advantages of Blender Vertex Colors
- Performance:
- Efficiency: Vertex colors are generally more performance-friendly than textures. They require less memory and can be faster to render because they don’t involve additional texture lookups.
- Simple Shading: Vertex colors can be used for simple shading and coloring tasks without the overhead of UV mapping and texture loading.
- Integration with Mesh:
- Direct Association: Since the colors are directly associated with the vertices, there is no need to worry about UV mapping issues like stretching or seams. The colors will always be correctly aligned with the mesh geometry.
- Deformation Compatibility: Vertex colors deform naturally with the mesh. When the mesh is animated or deformed, the vertex colors follow without any additional adjustments.
- Procedural Workflows:
- Procedural Generation: Vertex colors can be easily used in procedural workflows, where colors can be generated or modified based on vertex positions or other mesh attributes.
- Simplified Pipeline:
- No UV Mapping Required: For certain applications, you might not need the complexity of UV mapping. Vertex colors can provide a straightforward solution for adding color to a mesh without setting up and managing UV maps.
Summary
In essence, vertex colors in Blender provide a simpler, more performance-efficient way to color meshes directly through their vertices. However, they are inherently limited by the mesh resolution and cannot achieve the same level of detail and precision as UV texture mapping. For applications that require high detail and complex patterns, UV texture mapping is generally the better choice, while vertex colors are ideal for simpler, lower-resolution coloring tasks.
Please share the steps in video 
. I have tryed many times without success
Kindly share the steps of how to bake a model with texture to vertex color.
I’ve just been exporting .obj color files from TinkerCad into BS without the other file. Just the .obj and it works fine, just don’t hit “repair model” because that makes it monocolor again.
I followed this video, it worked (I downloaded OBJ + MTL + JPG from the Smithsonian archive to try this):
“Texture to vertex color using Geometry Nodes | Blender”
It’s a short video with no sound, but I used the latest version of Blender (as of today) and followed the steps exactly, then exported to a new .OBJ file which created a new .MTL with it. Dragged it into Bambu Studio and then there is a UI to map colors to the filaments that you have in AMS.