These days I am working on Visualizing Parametric Design for Revit. A very good start has been done by Ian Keough. He is working on a Revit add-in named Dynamo. Dynamo is an early exploration into programming for Revit. I have downloaded the source form github and trying to understand the code. In the next step I will add the "Mathematics Buttons" to Dynamo. Math nodes are very easy to implement, yet missing in Dynamo.
For those of you have problem installing Dynamo here is the process: