Parametric Curvalicious

Hey, Old-Timer . . . yeah YOU! The one who still remembers drawing perspectives by hand. Remember how to accurately construct an arch in perspective? Oh, it was painful, but you kind of liked it, didn't you? DIDN'T YOU!!

Well, it's your lucky century, CAD Monkey, because the temptation to make complex parametric geometry in Revit (or really anything on the market) can feel very familiar. The demand for needle-like precision, the iron discipline, the submission . . . It's going to be great! So grab your alligator clips and let's get started!
We're going to make a dome, but not just any dome, a fully parametric dome. Using basic geometric principles, you can control the height, the diameter, the oculus size, and the curvature of the surface, because let's face it, we're into control.

Props to Robert for posing the problem a couple days ago. Thank you, Sir, may I have another?
So, what else can you do with this method? For curves that need to flex 3 dimensionally, you can't go wrong with the curve-by-point method. Here's a panel that flexes an ellipse in 3d:

A similar method was used for the perforations in this dome: Made with this panel and some help from an API plugin:
Sample files can be downloaded from here


  1. Very cool Zach, the videos are so helpful, now I need time.

  2. hey New timer! yes you! yeah i did enjoy the intricacies of mechanical drawn perspective and i think architects would learn & pay a lot more attention to the things they are doing if they follow some of the techniques....

    by the way great post!..would study it and see what gives. btw, have you guys figured out a way or set up a utility that can unfold surfaces in Rav 2010? without this the massing tool is handicapped...pls let us know where we stand regarding this. thanx

  3. Sweet post Zac! You're really contributing some great techniques. I'm jealous ;p I like it when people raise the bar reaaaally high.

  4. Very, very cool....you the man!! :-) I am so looking forward to your AU class, assuming that it has been approved?

  5. Arman,my blossoming grey hairs beg to differ with you. Not sure what's in store for unfolding . . . but if you are able to do any coding, you should take a look at the API for something like this. I think that some clever use of "orient to plane" and draft views arranged on a sheet would get you much of what you want.
    David, not sure about AU, haven't heard yet. November is going to be so busy already, I'm not sure what to hope for.
    All, thanks for your kind comments.

  6. Can you upload that curtain panel over here?
    Thanks :D