Models I am provided with often have tons of tons of materials which tends to hang my host app. I used to go around this via Select > Select all by type > Mesh and clicking "Join" in the Tools tab.

Unfortunately this doesn't work for my latest model: "No mesh data to join". I've opened the MTL file in a text editor and noticed over 3400 "newmtl" definitions and most of these are duplicates, for example there are 1852 instances of:

Ks 0.000000 0.000000 0.000000
Tf 0.000000 0.000000 0.000000
map_Kd ff_644.png

All starting with a different name after "newmtl ".

I could theoretically remove the duplicate material definitions in .MTL and then re-assign the different material names in the .OBJ to match the one that's been left as a source but the whole method is a damn hassle and not a real solution to be honest.

Is there any decent way to clean this mess up?

Thanks in advance!

  • 1
    $\begingroup$ Welcome to Blender SE, @jokeUsa! It's a bit hard for us to figure out what's your problem here. What is your final purpose? Where does the MTL file comes from? What model is that OBJ file? Adding some informations should really be useful to help us help you. Thanks. $\endgroup$
    – Polosson
    Jan 25, 2016 at 14:32
  • $\begingroup$ Hello Polosson and thanks for replying. Well, going through my old models that i was able to "fix" i now see that they consisted a lot of meshes but their MTL files were about 5kb so i guess that my first example was unrelated? Unfortunately I can't post the model itself but the issue is as follows: the model has a 350kb MTL file and from what i was able to see, it contains a lot of material definitions out of which many, even though differently named, were exactly the same (see 1852 example above). Because of that, my host software (mObject which is a Motion/FCPX plugin) has issues opening it $\endgroup$
    – jokeUsa
    Jan 25, 2016 at 17:05
  • $\begingroup$ Here's a screen shot of the problematic materials list: postimg.org/image/m609e68rj So the question is: is there any simple way to merge the identical materials? $\endgroup$
    – jokeUsa
    Jan 25, 2016 at 17:05

1 Answer 1


Have you tried this ...

  1. Create a box object and apply a materials to it.
  2. Select all the other mesh object that has multiple materials you don't want in your scene.
  3. Select the newly created box object last. (Important select the box last)

  4. Hit CtrlL, select material from the drop down list.

  5. All your meshes should have the newly created box's material.
  6. Save your file, Close it and reopen it to refresh the data cache.
  7. Export the file to any appropriate format you may need.

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