Set Building
FirstStage contains a Sketchup-style 3d modelling and texturing tool.
You can model by drawing a shape on the ground with the Sketcher, then cut and extrude faces, or manipulate edges and vertices to turn a simple cube into any manner of shape. OR, you can create shapes and attach them to each other using the Grouper tool until you have assembled what you want.
New 3d objects created can be saved to your Asset Library via the Inspector.