Organic form challenge!

[mwagenbach]

I have been attempting to building a roof that has a somewhat organic shape (see sketch). The ridge line must curve in plan as well as elevation. Both paths are simple arcs, so were not talking totally abstract. I have been playing with the massing tools and trying to cut voids, but am having some difficulty. In this situation, the blend too would be perfect - start with a large triangle and have it sweep down to a smaller triangle (similarly to how the actually roof trusses would be). HOWEVER, the blend tool only works in a linear direction, not over an arc or curve of any sort. Any tricks or functions that enable good organic form modeling that might help here?

Thanks

-mike

[bowlingbrad]

(Bump)

I still can't seem to figure it out. I've tried all different ways with massing...

[Matt Brennan]

I had a related issue like this last week; a complicated roof with every point at a different elevation. In the end, we made the complicated roof in the new ACAD 2007. Using the loft tools as well as changing the vertex points, we were able to import the dwg into Revit.

But… here is the catch. Before I imported the dwg into Revit, I created a new mass family. Once I was at this point, (in which we could create solid and voids), we imported the dwg, and finished the mass. At this point you can now texture/map walls, roofs, curtain walls and so to this new mass. This is a new Revit Building 9 feature in which it also works with sketch-up too!!!

Good luck and if you have any questions, please do not hesitate to ask.

[Matt Brennan]

The base would be a simple extrusion but for the roof you would use the method above.

[Steve_Stafford]

Here's one approach all within Revit...

Made a thick roof by footprint then used an in-place roof family with two void extrusions to carve off the two slopes. Hard to say how close it is since I don't have any real dimensions to work from. Also unless it is pretty large the arc of the ridge in elevation is pretty subtle.

[davidcobi]

Tried importing a loft shape into Revit. It seems to import fine. Then we tried to pick Wall by Face. The result is a broken form.

[mwagenbach]

What program did you make the loft in? I started some stuff in SketchUP but have not gotten around to importing them. Even if it did import right, I would need the roof by face option to work properly and it seems, at least with your form, applying walls/roofs by face did not work... Hmmm, seems like creating everything in Revit might be the way.

-mike

[davidcobi]

I used AutoCAD 2007 but this was a first attempt. There maybe be certain forms that just don't work.

[tamas]

Tried importing a loft shape into Revit. It seems to import fine. Then we tried to pick Wall by Face. The result is a broken form.
Could you post this file (both rvt and the original you imported from) so we can diagnose the reason? Ideally you should do it through Revit support.

Thanks,

Tamas

[mwagenbach]

Thanks Steve and everybody else! We don't have 9 installed yet, but will in the next few days, so I'll just have to wait to see exactly how you did it - the image looks right on though.

Anybody else have organic form issues or successes? If you are creating forms in other programs, which ones and are there any key settings?

[Steve_Stafford]

The roof surface you are after is basically the outside surface of a tapering conical solid, if you imagine the opposite of the roof. So I made a solid block of a roof and used two voids to carve away the solid.

The key is to define a workplane that is perpendicular to the surface of the roof. You have to derive the pitch of each side and then sketch a reference plane perpendicular to them. Orienting a 3d view to each of these reference planes makes it possible to sketch the shape of the void "cone". Technically I should have used a blend void to cut the roof but I just used an extrusion with arc segments. A blend would allow for greater deflection along the ridge.