I went through the ugly process of setting up decent cut/fill coloring, only to watch my computer come to a crawl when doing anything once the 2d solids were displayed.
I have a fast machine, plenty of RAM, and other things went fine with the volume surface I was dealing with.
This is not the first time things have failed because of this.
I will not have to investigate doing my own coloring routine, and also c3d competitor programs for doing a task that should be absolutely slick in a civil program that claims to be BIM.
The root of the issue is my volume surface was large (wrote to the mms file...). I knew it but could not do much to make it smaller.
So some way of simplifying surfaces is becoming critical to doing things in C3D.
I'm not talking about simplifying point data on a surface, we use contours and breaklines from real aerial topo.
The problem is some areas do not need the 1ft contours to define the ground shape, and some do.
Its slow to separate the two, we need some routine to analyze the surface and decide where faces can be combined.