I’m taking 3D scans of pieces, and needing to import them along with their materials into SketchUp. I have successfully imported the .obj file, but the materials are not coming with it. The .mtl file is in the same folder as the .obj file @thomthom can you help me figure out why the materials are not importing as well? Here is the piece I am using as a test.
mesh test.zip (2.4 MB)
Your OBJ file is poorly written.
What are you using to make it ?
The OBJ does NOT define the MTL file that to be used to define materials.
And anyway, no faces are assigned a material - irrespective of its existence in the MTL !
The MTL file also assumes the image files are to be found in its own folder - the normal convention is:
Textures/tex_0.jpg
So it is somewhat unconventional.
So to recap…
Currently your OBJ has no contact with its MTL.
The MTL is also setup to use image files in its own folder - rather than the the more usual subfolder of texture images…
I am using 123D catch to take the 3D scan, but then having to open it in meshmixer to reduce the polygons re-saving afterward so that I’m able to import it into SketchUp without it taking an hour minimum just to import the file.
But as I explained yesterday…
The OBJ file has no reference in it to its MTL file, so no materials are made.
Also no materials are specified for faces anyway.
You could try adding:
mtllib mesh.mtl
at the start of the OBJ file so at least the materials defined in the MTL file get made.
BUT then the issue is how to assign them to the faces.
Since there’s only one group defined you need to know how to allocate materials to faces - since you have messed with the mesh I think it’ll be impossible to do that…
Have you considered importing the more complex OBJ with materials into say Blender ?
Then simplifying it and exporting as OBJ again…
So is it Meshmixer which produce this OBJ without MTL reference? No export options?
Please forgive me, I’m very new to this, have no coding experience to speak of, and I’m really just feeling around in the dark.
I can’t attach the zip folder that I dowloaded straight out of 123D Catch, it’s too large. But here it is on the website, and the files can be downloaded from there. Versa Connector (TNDCI DEV) 0.0.1 - Sign On if you want to take a look at the raw file.
In that previous one from yesterday, I had opened the .obj file in meshmixer then reduced the polygons by something like 95% because I really don’t need the level of detail it has originally (plus my computer just can’t handle that size file and it takes several hours to open in sketchup then often crashes). So after reducing it I export it as a .obj replacing the much higher polygon count file. I suppose that screwed it up enough that it doesn’t recognize the necessary MTL references. No materials show up in meshmixer when I open it in there either though.
I’m downloading blender right now like @TIG suggested maybe it’ll work better. I’m just too used to sketchup, and have little to no experience with any other program. Like I said, feeling around in the dark! 
We can’t download the linked file unless we are members.
Can you link it to a public sharing site - lie DropBox ?
When you ‘downgrade’ the mesh are there no options to keep materials etc ?
HAHAHA! I did it!! For some reason when exporting the new reduced polygon mesh from meshmixer, it was adding some quotation marks to the mtl reference in the obj file code. I got rid of them and it properly referenced the mtl files when importing it into sketchup and it’s beautiful!
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Thanks guys, I appreciate your insight 
A miracle 
Lol. Hey, for me, it was!
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