@dadwill said:

I am using version 3 of IRender nXt and it does not take into account section cuts so it renders whatever is in front pf the section cut.
If anybody has an idea please let me know?

Thanks

IRender nXt does use Section cuts. It looks through the section cut to see what is inside of a room, etc. However, the geometry in front of the section cut is still used for lights and reflections. This is important in most cases, because you want to see that a room looks like, but you may not want to have to place the camera inside of the room with a wide angle lens.

If you are not getting section cuts, make sure they are enabled properly on the nXt Setup tab.

http://wiki.renderplus.com/images/thumb/4/4f/Section_plane.jpg/500px-Section_plane.jpg

Section cut through a SketchUp model.

Note: Even though you use a section plane to remove geometry - such as this front wall - the illumination inside is not changed. (The sun does not shine in through the now-open wall - and still creates shadows from the invisible windows.)