Mesh3d update intensity (colormap) in real-time of obj

Hy everyone. I have successfully displayed .obj file, but I don’t know how to continuously updated only intensity of the object. Take into account that .obj file has 100 000 points and that it takes about 5 seconds for figure to be displayed. Basically, only colormap should be changing every say 1 second.

If someone could just give some code example, even with basic .obj pyiramid or some other simple object, I would be most grateful.

Thanks in advance for your help!