I have been using Google SketchUp for my woodworking project planning. SU is a great tool for prototyping and figuring out accurate dimensions. I have found it very useful to catch many errors in my spatial thinking.
Personally, I find it hard to sketch interactively all the time. I have always liked the text-in-graphics-out style the most. So, I ended up learning enough of SU API to create plug-ins. I have a plug-in to create a rail I will work on the stile soon and post another entry on it.
The table I am planning needs a bead but my plug-in can only do a bevel at this time. I have to research some more to fix this issue, but that is lower on my list of items.
The script is at http://docs.google.com/Doc?id=dgh832np_27c73cd5gw. Save the text to a file in SketchUp’s plug-in directory and restart it. You should see a new Draw->Rail menu item which will start by asking for dimensions and proceed to create a rail.
Here is an image of the generated rail.
-- Praki, Aspiring Woodworker