[Solved] Unable to find object names in obj

Troubleshooting import-assets
1

Greetings,

I have exported the obj from blender. The model contains many objects with all unique names. The obj file looks like this:

o Lower_Leg_L_Lower_Leg_1
v 0.592870 -3.073410 0.034250
v 0.611490 -3.074640 -0.095880
v 0.433000 -3.074250 -0.043560
v 0.480600 -3.072670 0.118800
v 0.340450 -3.072860 0.108250

I can convert to j3o file format without any errors. I can also load the model into the scene without any problems. However, I want to change the color of different parts of the model. RIght now, I can only change the entire model's color. If I try this
[java]Geometry submesh = (Geometry) newBody.getChild("Lower_Leg_L_Lower_Leg_1");[/java]
I get null returned.
Any ideas of what I need to do in order for JME to recognize separate objects loaded from a model?
Thanks
2

The objects are divided by material so creating different materials per mesh part should result in multiple geometries.

3
normen said:
The objects are divided by material so creating different materials per mesh part should result in multiple geometries.

When I export with a material; the material is set in the mtl file. When I try to convert from obj+mtl to .j3o, I get a null pointer exception. Any ideas of why this might be? Note, the obj file contains usemtl (null) throughout. In order to get jme to convert to j3o without mtl, I have to delete the lines with usemtl (null).

Thanks for your help.
4

That material must to have the same name of its .obj model. For example : mymodel.obj mymodel.mtl

5
glaucomardano said:
That material must to have the same name of its .obj model. For example : mymodel.obj mymodel.mtl

Yes. I have the problem when both obj and mtl are named the same.
6

The material-library-file must have the name it has in the first few lines of the obj-file.

mtllib yourfile.mtl

The problem why your code doesn’t work is following:

  • according to obj-specification, you can separate your model into sub-models by using the “o” tag.
  • reading OBJLoader.java you will see there is no separation by the “o” tag. jme3 only separates the model by the various materials used and it names the sub-spatials after the materials.

    This “feature” isn’t implemented in jme3 (yet, I hope).

    http://en.wikipedia.org/wiki/Wavefront_.obj_file

    P.S. if you delete the usemtl material-name tag, you will have no more materials.
1 Like
7

Thanks doe300. I have found that I needed to apply a material to all objects in Blender then export. Its working now! The naming of the submesh seems to be something like this

Body2-geom-0, Body2-geom-1, Body2-geom-2

But the materials are named pants, skin, shirt.

Thanks for your help!