Let me be the first to admit I have an unhealthy relationship with my software. But this is too cool to not gush about.
Harry the API Guru did a course on using the API in the revit 2010 massing environment at AU2009 just a few weeks ago: "Creating and Analyzing New Conceptual Massing Geometry With the Autodesk® Revit® API". Unfortunately, I was unable to attend, but I was given the opportunity to test drive some of the tools he made for the course before hand. Hands down the best one yet is Harry's SetParamFromImage.
Conceptually the tool is dead simple. You have a bitmap that is 12x12 pixels. You have a divided surface that is 12x12. The panels in your divided surface contain a parameter called Grayscale, and the API will write a value from 0" (white) to 12"(black) based on the pixel values of the image. Tah dah!... Continue to rest of post and pictures...