A matte shader, or Occluder Object, is created in order to hide whatever geometry is behind the geometry with the matte shader applied.
In an AR experience, for example we can use a matte shader in order to achieve a "World" or in order to hide certain parts of geometry, like characters or objects that are hidden in certain moments of an experience or animation.
There is a quick and short process in order to be able to use a matte object, next we will explain how to do it from Maya and 3DS max.
Create a new shader and name it matte, it does not matter what kind of shader, however we recommend it to be a lambert shader.
We apply the shader to the model we want to use as a occluder, and then we export it as an Open Collada file (DAE) together with the rest of the experience.
Once we have the ,dae file we open it with a text editor, we recommend Notepad++ as it is a free powerful program.
Once we have the file open we press Ctrl+F in order to open the Find Window.
Next we search for "matte" (without quotes) until we find effect id="matte-fx" as shown in the example above, then we manually add the code: name="matte" as shown in the example below
Then we overwrite the dae file with the new version and we use the dae as a regular dae and add it to a tar file in order to add it as a 3D overlay to the studio.