Meshes are built face by face, but there are many ways to construct them in Toxiclibs. For starters, Toxiclibs has a few SurfaceMeshBuilders to create meshes using Paul Bourke's SuperEllipsoids and SphericalHarmonics code, but those are perhaps not what you are looking for now. Also, there are many different routes to end up with a mesh and convert between them.

Here, you could write a method that constructs the prism shape based on a few parameters. This will make it more flexible and allow you to write the code once (aka solve it) and then use it with different parameters. What I mean is don't calculate it yourself in the sense that you hard-code coordinates, just write a method that will solve it flexibly for you.

I release the above is a somewhat abstract answer. A more concrete tip would be that you could start with a Polygon2D and then use the toMesh functionality.

Also, what kind of prism do you want when you say the top and bottom polygons are different?

Hey Chris, long time no see :) Just v.briefly... If you merely want the top and bottom to be different sizes, but same shape, you could just create a cone with different radii for north/south cap and sample it at resolution=3 to turn into a TriangleMesh...

Hi guys, the two polygons (north and south cap) will have the same amount of sides. Just different dimension and proportions between the sides. Maybe even a rotation :)

I think I did it

Ok, "the points visual debug" was the face normals :)