MTL and OBJ and JPG problems with OBJLoader

[alexs7]

Basically what was mentioned here: https://github.com/mrdoob/three.js/issues/16395.

All I did was to change the model loaded in this: https://threejs.org/examples/?q=obj#webgl_loader_obj2.

So the resulting code is:

var onLoadMtl = function ( materials ) {
  objLoader.setModelName( modelName );
  objLoader.setMaterials( materials );
  objLoader.setLogging( true, true );
  objLoader.load( 'models/obj/my_scans/Model.obj', callbackOnLoad, null, null, null, false );
  };
  objLoader.loadMtl( 'models/obj/my_scans/Model.mtl', null, onLoadMtl );

But the model will not load. The model will not show up, and no errors come up…

Any ideas ?

PS: The model loads fine in MeshLab

[looeee]

Can you share the model?

[alexs7]

Model.zip (570.1 KB)

There it is

[Mugen87]

You’ve ran into the following issue (it’s about the ambiguity of the tr statement):

https://github.com/mrdoob/three.js/issues/12861

You can solve the issue by creating your MTLLoader like so. This will invert the semantic of the transparency definition.

const materialLoader = new THREE.MTLLoader();
materialLoader.setMaterialOptions( { invertTrProperty: true } )

Result with OBJLoader:

[Mugen87]

BTW: One more reason to use glTF instead of OBJ. More information about this topic:

https://threejs.org/docs/index.html#manual/en/introduction/Loading-3D-models

[alexs7]

@Mugen87

three.js docs

Thanks! It worked. I was also using an outdated version of the loader.

[dongmei_wang]

Hello, my 3d model is composed of obj file and texture (MTL + JPG), I don’t know how to load JPG.My model is shown in black.Can you share your code?Thank you very much!

[Mugen87]

I’ve already shared the code for loading MTL (with textures) here:

3d model has no texture, it is black, how to add texture?

It’s seems something went wrong during your upload… Anyway, the following example demonstrates how to load OBJ/MTL files. Maybe it’s a good resource for your own code: https://threejs.org/examples/webgl_loader_obj_mtl

Have you actually tried this code? If so, please share your current work of progress as a git repository.

[dongmei_wang]

Thank you very much for your careful answer. By changing the value in the MTL file, my model has texture, but the back of my model is still black. I think it may be the problem of setting the light source, but I don’t know how to adjust it.

[dongmei_wang]

wdongmei/3D-model

[Mugen87]

@dongmei_wang

I think it may be the problem of setting the light source, but I don’t know how to adjust it.

You are just adding an instance of SpotLight right now. Try to add an ambient light next to your spot light like so:

var ambientLight = new THREE.AmbientLight( 0x404040 ); // soft white light
scene.add( ambientLight );

[dongmei_wang]

Thank you very much for your answer. It was very effective and helpful.And then I’m going to have to adjust the axes, hopefully to fit the model.