Wesche - FreeDrawer

Wesche, G. and Seidel, H. 2001. FreeDrawer: a free-form sketching system on the responsive workbench. In Proceedings of the ACM Symposium on Virtual Reality Software and Technology (Baniff, Alberta, Canada, November 15 - 17, 2001). VRST '01. ACM, New York, NY, 167-174. DOI= http://doi.acm.org/10.1145/505008.505041

Summary

Electronic pen you can use to draw in 3D space. To make things simpler for their algorithm, you're restricted to spline curves. You trace out the general curve with the pen and the computer calculates the parameters of the spline. You can draw curves, modify them, connect curves together to form a network, fill in surfaces between curves. You wear wonky VR goggles to see what you're drawing.

Discussion

Tradeoff between user freedom (virtual clay) and performance--they choose performance by limiting a user's drawing style (restricted to splines). They claim this is easy because it has closed form representation, is easily transferable (just the parameters of the splines and not every voxel need to be transmitted), and computationally cheap (storing every voxel for virtual clay is expensive).

They admit you need an artistic flair and a little bit of training to get used to using the splines. Well then why not just train on a CAD system? Isn't the point to offer an intuitive interface with no need for training or restrictions? Plus, if you use CAD, you don't have to use /just/ splines, can be precise and exact, and don't have to wear wonky 3D goggles.