Forums >> Revit Building >> Technical Support >> Elliptical wall design causing headaches (2011)

snowyweston

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Our office is starting out on quite a large scheme enclosed by an elliptical perimeter wall - with the design/construction presently at the point where the intent is to maintain a smooth curving brick facade for the outer skin, and a faceted (to timber dimensions) internal skin.

Having worked with ellipses in Revit before, (but never on such a scale of size or complexity) I was quite nervous of the design, mainly down to the number of "Revit can/can't" conversations I was going to have with my office peers who look to me for a great number of answers.

My proposal seemed sound, model an extruded ellipse mass and host to face - which has sufficed so far with work up to design concept and planning - but now the work's moving forward and despite being keen to keep as much in Revit as can be I just keep drawing a blank on how to go about it.

I've just been experimenting with using two-concentric ellipse extrusions in the same mass, one to handle the face-placement of the smooth exterior, the other to handle the interior wall - for which I thought to use a curtain system (to keep it faceted) but straight away the inability to use basic wall type in a curtain system (?) stumped me. Then I used the curtain system's panel faces to "pick" the placement of a (basic) internal wall type - which (once the curtain system is hidden from views and filtered out of schedules) gave me nearly what I needed.... but....

Inserting windows (and doors) in either the exterior or interior "skin" wall doesn't allow me to use any combination of cut/join modifying tools to cut both walls with the elements, as per the attached jpeg.

(green=mass, red=ext. skin wall, blue=int. skin wall, black=curtain panels)

I guess we could coordinate openings in one of the walls to follow the openings in the other; but before I propose as much (to the cries of disbelief that will only fuel dissatisfaction with Revit) I wanted to ask here if anyone might know a better method I might employ for such a task?

Here's hoping...

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WWHub

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Why use a true ellipse, are you a purist?  When we drafted, we never drew a pure ellipse because you really can't.  They are also hard to define for construction. 

So why do it?

When we hand drafted you created a very nice "visual" ellipse using just two different radius curves.  Very easy to draw, define and REVIT can handle these.  

Nobody will ever know the difference !!!!

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snowyweston

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I'd like to think I was a purist, but there's nothing pure about THIS ellipse, it's exceptionally contrived and nothing like anything I would design. But despite me thinking it'll end up looking like a dogs dinner, my director, the "designer" in-charge, is adamant.

As such I still need a solution, so I'm curious for a bit of clarity on what you mean by "two different radius curves" especially given this part of your post :"Very easy to draw, define and REVIT can handle these.".

Thanks

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WWHub

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When we hand drafted and needed an ellipse (before templates '60's), we always used an approximation as described in the first link below. 

This link shows how close an appromation is to a real ellipse - note that very long, thin ellipses donot work as well.

 http://www.uwgb.edu/dutchs/MATHALGO/Ellipses.HTM

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snowyweston

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Their heads will explode when they open those links!   : D

So your suggestion is to build an approximated-ellipse mass family and continue that way?

Or draft / use a linked .dwg that follows those approximation-methods for wall placement?

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WWHub

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mbsteve

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