My first suggestion would be to get a copy of lightwave/maya, etc. Although, having taught 3D for a number of years, even many advanced students would struggle building a (high quality) cat using a modern modeler. Assuming you actually want to plot the thing, I have 2 suggestions (neither terribly good.)

1. To get a better sense of how to control cubic style curves, render control and anchor points on a simple curved object and add mouseEvent behavior to tall the points. This will at least give you some visual feedback as you deform the object. You could take this one step further and actually output coordinate data as well. Pushing this further yet you might even build a simple 3D modeler in Processing, which wouldn't really be all that difficult,(if one had lots of time and/or a very understanding boss.) I'm sure others on the board would be very interested in a project like this.

2. The simplest solution would be to break the cat down into simple shapes and build each part separately. Of course, you're not going to get a seamless, smooth mesh that way, but you could probably get something cat-like.

Then of course there's always 3dcafe/turbosquid...

ig