If I import the FBX file into Unity, the colours don’t show up either, but there I can make them appear by changing the shader type to “Sprites/Diffuse”.
Do you have any textures for your model? I’m not sure if we import vertex colors from FBX files - I think we do but need to ask @will or @Mr_F.
If you have separate mesh instances for the different parts of your mesh that have colors you can assign a different material with the desired color on each mesh instance through the Editor.
ParaView colours the mesh through the vertices, so no; I don’t have textures. I would imagine that colouring by vertex is pretty common if you want the 3D models to be small. Are you suggesting that this is rare in FBX files?
I suppose that assigning a different material to each mesh only works if each mesh is of the same colour, right? That is not the case: the mesh has many different colours.