New in Photoshop CS3 Extended is the ability to import 3D objects in various formats (.u3d, .3ds, .obj, .kmz, and Collada file formats) as a Photoshop layer. While no substitute for true 3D rendering applications, this new feature adds a new dimension to collage rendering. For this example we'll be using this photo from everystockphoto.com and a 3ds model of a patio table.
To import the 3ds model, select Layer->3D Layers->New Layer from 3D File... and select the .3ds file to import.
After importing the 3ds file, Photoshop creates a new 3d layer of the object. Double-clicking on the layer icon in the layers palette reveals the 3D layer transformation tools which allow for positioning, rotation and sizing of the imported object.
Using the "Drag" and "Slide" tools to position the patio table in an appropriate perspective of the scene yields this finished image. (Press <enter> to accept the 3D transformation just like the Free Transform command.)
If the imported object includes any associated textures, these textures can be edited by double-clicking on them in the layers palette. New textures can't be created and existing texture mappings can't be modified, but the standard Layer Blending options will work with 3D layers (drop shadow, outer glow, satin, etc.). Additionally, modifying the structure of the model itself still requires the use of a bona-fide 3D editing application. (Why not give the open source alternative Blender a try!)