Working on a fun project and i've really found it enjoyable to make some props for the project. However, there is a bit of a snag I want to fix and could use some help. This part isn't "Crucial" to the overall project as its just for fun, but I do feel it would add more atmosphere to it all.

Downloaded a free 3D graphing calculator program and want to create a mathematical formula to simulate a sort of cone/tube. This would represent a portal in the project, but it's been SOO long since i've done Trigonometry, Geometry, and such that I don't know where to begin.

Any math wiz people here that have an idea of how to create a tube/circle in a 3D graphing calculator?

err... I can do that in Python with NumPy/SciPy and matplotlib

dunno about 3d graphing calculators