DracoLoader how to read custom attributes

[Lital]

I have a PLY file with a custom attribute of values, which I would like to load and use. Is there a way to do that?
In the PLYReader I saw there’s an option to map custom attributes to default attributes, is there a similar option for dracoLoader as well?

Here’s an example of a header:

ply
format binary_little_endian 1.0
element vertex 27549
property float x
property float y
property float z
property float Depth
property float Points
property float Direction
element face 54252
property list uchar uint vertex_indices
end_header

I would like to read the Depth attribute.

[Mugen87]

@Lital

In the PLYReader I saw there’s an option to map custom attributes to default attributes,

Can you please share the code that performs this mapping? AFAIK, PLYLoader just supports the mapping of custom property names to default names.

[Lital]

I was trying to use this code, but the mapping actually didn’t work for me, not sure why.

import { PLYLoader } from 'three/examples/jsm/loaders/PLYLoader';

.

this.plyLoader = new PLYLoader();
this.plyLoader.load(visualModel, (geometry) => {
geometry.computeVertexNormals();
this.plyLoader.setPropertyNameMapping({
Depth: 'position'
});      

  mesh = new THREE.Mesh( geometry, material );

  mesh.scale.set(2, 2, 2);

  this.scene.add(mesh);

  this.loading = false;

},

( xhr ) => {

  console.log( ( xhr.loaded / xhr.total * 100 ) + '% loaded' );

});

[Mugen87]

PLYLoader.setPropertyNameMapping() does not work like that. Consider vertex colors. You normally define them like so:

property uchar red
property uchar green
property uchar blue

However, you could have a PLY asset where the definition is:

property uchar diffuse_red
property uchar diffuse_green
property uchar diffuse_blue

You now have to define a property mapping otherwise PLYLoader is unable to load the asset:

loader.setPropertyNameMapping( {
    diffuse_red: 'red',
    diffuse_green: 'green',
    diffuse_blue: 'blue'
} );

That is required since PLYLoader looks for a fixed set of data/properties. If you have additional values in your asset (like Depth), it’s not possible to parse them without modifying the loader.

[Lital]

Oh, ok. Thanks for the clarification.
Is there a different loader that does support this functionality? Perhaps GltfLoader?

[Mugen87]

Not that I am aware of, sorry.

[Lital]

Ok. Do you know where I can find a list of the fixed set of properties the plyLoader (or better yet the dracoLoader) support?

[Mugen87]

I suggest you just look into the source code^^.

[Mugen87]

Thanks to @alankalb at GitHub, it will be possible with r147 to load custom attributes in PLY files with PLYLoader, see:

PLYLoader: Allow custom attributes.