How to set GroupIds (c1) in object (.obj) file?

I have an object file and am trying to use ParaViewWeb Visualizer to visualize it. I would like to use GroupIds to present different sections of the surface in different colors. How can I set these in an object file?

You do not seem to be in the right category, I’ve moved your topic.

The VTK reader of OBJ does not actually split the geometry in group such as a multi-block. But in vtk.js we do have that freedom. Taking the vtk.js implementation of the OBJ reader and converting it in Python as a Python Plugin Source would allow you to produce a multiblock and start leveraging coloring and visibility control within ParaView and therefore in Visualizer.