Custom Elliptical Stair

[Beaglemommy]

I need some ideas....How would you model these stairs in Revit?

[mlgatzke]

I'm sorry, I guess I don't see the dilemma. I would model one flight, then mirror it to the other side. The landings would be made from floor entities. It would have to be modeled specifically. It's not exactly something that could be modeled using the "Run" function. The railings would be made the same way.

Am I missing something?

[sbrown]

You will need to do some layout first.

Draft the stair you have drawn, then just use the stair tool, picking the edges as boundary lines and the steps as riser lines.

Or to use the run tool, you need to create the ellipse as 4 arc segments, then offes 1/2 the widht of the stair and then use the run tool, arc.

[patricks]

So can you draw actual elliptical stair boundary lines? But the run line cannot be elliptical. Right?

[dhurtubise]

So can you draw actual elliptical stair boundary lines? But the run line cannot be elliptical. Right?

Not totally true, you still won't have the ability to sketch ellipse line even while using the boundary tool.

[Dimitri Harvalias]

you need to create the ellipse as 4 arc segments, .

As Scott noted, no ellipses available with the stair sketch.

[mruehr]

i use a three-center arch setup to draw the Run Arc
then i use Tangent Arcs to refine the boundary lines

if you want to have a really good result you may consider a five Arc setup and not using
the Run tool
http://mysite.du.edu/~jcalvert/math/ellipse.htm

[clog boy]

mruehr is right... use multiple arcs, you can make them smooth by first drafting two bigger arcs, and draft the third one inbetween and make it's radius perpendicular to the other two arcs. Then trim.
Eventually you'd have to draw each riser individually. If I may make a suggestion, draw the first perpendicular to the boundaries, offset it to the appropriate distance and draw a new line that's perpendicular to both boundaries. Repeat until done.


Or use a pdf-to-dwg utility, load the dwg as an underlay (if scaled to the appropriate size) and pick lines. (duh) Most converters have a trial period, and for this purpose it doesn't mind if the app inserts a water mark.

[geo2mia]

I have the same situation I have drawn the elliptical stairs in AutoCAD and linked to Revit. Revit boundary tool will not pick the elliptical arc.

[mthurnauer]

I have used the five arc technique and had very nice results. I have often come up with designs that rely on a two arc solution that provides a nice fuller shape and makes for a much easier stair to both document and build. For example, with a two arc solution, if using precast treads, you would only have two different tread types to cast and two different forms required for rolling an helical curved handrail.