Does anyone out there know a location from where I can download free timber frame design software?
Alternatively, does anyone know of a software program for sale, specifically for the designing of timber frame homes, allowing for bent structures and SIPs design, etc?
Gary is right. Sketchup is an ideal program for designing a Timber Frame as well as the sips enclosures. Here is a link to the latest version.....http://sketchup.google.com/product/gsu.html
The free version will serve you just fine. Once you download it you can go to the "warehouse"..... here http://sketchup.google.com/3dwarehouse/ There are projects there you can download and see how they were designed.