Last night I was working on a rather complicated (for my level of experience) model, and I really found some issues with the way Sketchup was doing things.  One was while trying to use the follow me (and the follow me and keep plugin) I was not able to extrude a square tube along a helical path (weird errors like the outside faces would disappear), However what I had the most issue with was when attempting to cut the model in 2 (e.g. I wanted to delete everything above a certain point)

Now I was able to View the point of cut fine with the section plane, however when I tried to intersect the model with a rectangle along the same level I would get all sorts of extra artifacts, edges and faces appearing out of nowhere.  I am really surprised that there isn't a tool that can cleanly cut the model like the section plane.  Is this common throughout different 3d modeling software, or is this a quirk of sketchup?

The cutting sections thing is a big stumbling block for me because as I wait (more patiently then some it seems) for dual extruders I want to be able to quickly and easily cut up a model in order to separate the different colors.

Thanks!