As Vellum has gone through revisions it has grown slightly in size, while the capabilities have advanced at a much faster rate. Vellum has not become a behemoth, such as the likes of Microsoft Word. There are two versions of Vellum. Both versions have identical features and capabilities, the difference is that one is built to run on the Power Mac, the other on the 68k Mac. It's a real benefit that Vellum takes advantage of the Power Mac's speed, but it would be nice if you didn't have to buy a different version of the same software.
Vellum requires a floating point unit to run.
This means that the 68K version of Vellum won't run in emulation on a PowerMac. Software FPU is available to solve that problem but there is a performance penalty. It makes a difference when selecting upgrade options. This is an enormous time saver. The more traditional method of drawing the 3D model on the computer, plotting the drawing on paper, sending it to the machine shop where they take the drawing and rebuild the 3D model is simplified.