I'm trying to create my first equation generate curve.  It is a compound parabolic concentrator.  Here's a picture with the equations and variables:

In the yellow box you can see the error message.  I do not understand why the curve exceeds the maximum model size.  Here's a screen capture from Mathcad that shows the dimensions:

I really don't see why an object 4.346 mm long and 2*2.546 mm in diameter is too big for SW.  Any ideas?