With all due respect, I believe this CAN be done, but not with the simplicity and not as "live" as in Sketchup.
In the 3D OpenGL view, your "section line" would be a large block used to SEO the target object. You'd pull the block around and push it into the object where you wanted a peek. This could be quite slow depending on the complexity of the model.
I suspect that with a little GDL, this large block could be moved to SEO the model, being moved through the rebuilt-every-frame model with code linked to the animation frame like we do with the opening door trick.
Any GDL experts want to tackle this one with a short script for a parametric block with a displacement link??
Ah, sorry, missunderstanding your question, I think Dwight is on the right way. I think it could be done with GDL and the part in GDL where you have a part that coop with SEO but isn't visible to the eye. And a timevalue that make the GDL object change size on time-axis.
Whew...this is all overwhelming to me....Im not that advanced a user yet. I hate to be a bother but could I perhaps get a more mid-level explaination?
I think I somewhat get the main concept: each frame would have the section plane move just a fraction more, correct? I know I can manage this, but once you get into the cameras, key frames, etc stuff then I get a bit comfused as Im just in the past day or two beginning to explore this feature.
I believe I can just do as you say, then rendering each frame with, say, a 1" move or so, then compile the files into a video. Certainly more tedious but shouldn't be too difficult overall. Good enough until I can manage my way around scripts and all that jazz.