Preview 3D sectors.

If there any plugin, or a version of Doom Builder, that lets you preview 3D sectors in 3D edit mode? I'm working for a large map for Gzdoom, and its a pain having to guess heights/texture alignments etc. for 3D sectors.

Unfortunately something like that does not exist.

From the Plugin Ideas thread on the DB development forum:

ZDoom Editing Plugin
Slopes, 3d floors, colored sectors, translucent walls, etc. This is not something I would do on my own. Something for Graf Zahl and/or Randy to help with.