>My current thinking is that I may write a very simple and quick renderer that will be built in to do very basic stuff, but rely more on >plug-ins / 3rd party type renderers for more advanced type things.

That makes a lot of sense to me as well Michael. I've always liked that idea for some reason.

For example, there is an easy sketchup to kerkythea plug in, and Cycas has an inbuilt portal to povray. Though the two systems are a little different.

In both systems, it is possible to set up cameras, lights, materials inside the modeling program. In the first system, the scene is opened in KT and the rendering operation is controlled from there.

In the Cycas system you don't have to talk to povray at all. A very workable range of render settings can be selected from within the modeler. Which may be very good for some users who don't have time to get into the deep subleties of rendering.

Just some thoughts.