FreeDrawer – A Free-Form Sketching System on the Responsive Workbench

[Summary]

This paper presents a sketching system for spline-based free-form sufaces based on a 'Responsive Workbench'. They propose 3D tools for curve drawing and deformation techniques for curves and surfaces. The user directly draws curves in the virtual environment, using a tracked stylus as an input device.

They claim their interface has the following advantages: closed-form parametric representations, easy transfer into standard CAD packages, fast triangulation and evaluation algorithms, infinitesimal smoothness of curves and surfaces and efficient deformation algorithms based on variational modeling.

A drawer can draw in the virtual 3D space freely to create a curve network. One can also change it after creation. After this, surfaces can be filled based on these created curves. They also offer a variety of modification tools: curve smoothing and sharpening, curve dragging and surface sculpting. In this paper, they also demonstrate how a drawer can create a seat by going through the above steps.

[Discussion]

I like this paper because the usage of splines is pretty clever, which avoids possible undesired curve shapes when drawing in 3D. But the biggest problem, I think, is that how a naive user is able to know which curve he or she should draw. Take look at the teapot result, it's probably hard for me to draw this. In addition, it seems this system can only generate some simple 3D objects.