AutoCAD 2007 has the ability to create 3D DWF files with materials.
Download ACAD2007_Materials.dwf (1200.1K)
This file requires the free Autodesk DWF Viewer 6.5 for viewing, manipulation, and printing. Viewing via Autodesk DWF Composer R2 results in an error:
Viewing, manipulating, measuring, marking up, and printing via Autodesk Design Review 2007 is on its way.