Drawing a Double Parabolic Roof

Hello all,

I’m new to Rhino for Mac so I apologise if this is a very basic question.

I’m trying to model a double parabolic roof something like the attached image. I’d like a true parabolic curve to be along the long and short axis of the roof and the perimeter to be as the lozenge shape shown. I have drawn this from 9 free form curves that have been lofted and then blended. I don’t have access to RHINOMEMBRANE is this needed?

Any help appreciated.

Many thanks,

(My comments are based on Rhino for Windows.)

The Parabola command draws true parabolas. Parabolas can be non-uniformly scaled using NU and will remain parabolas.

Are you looking for something like this: Parabolic roof DC01.3dm (163.4 KB)


Thanks for your reply.

The model you sent does answer the question but I think I asked the wrong question!

The curves on the model I posted are Splines “S” shapes and this is what I am after so the roof flattens towards the edge. Perhaps this makes makes no difference, what you seem to have shown is splitting into quarters and presumably lofting a segment?



I created one quarter using Sweep2 and then used Mirror to create the other three segments. If a single surface is desired the segments could be merged using MergeSrf.

How much have you done in Rhino previously?

Thanks David,

I’m a complete novice as I’m sure is apparent.

This is a sketch of what I am trying to do.


I don’t know how precisely the model have to be but for that sketch, you can model it by revolution and then, scale 1 dimension to get it longer like the AA section.

Your curves are not parabolas.

You might want to take time to go through the online Rhino for Mac tutorials. https://www.rhino3d.com/tutorials