Modeling straight purlins on a curved roof

[Peter1232]

So I have a curved roof I want to model some purlins on. They will be 2x4's laid flat. I don't want them to curve in plan - these will be straight members laid directly on top of the roof - they are not curved. The result will be a slight bend in elevation of the members as they attach to the roof.

Does anyone have any suggestions on how to go about modeling these? The beam family doesn't seem to be able to work in such a fashion. Can I make a face-based family that will attach to the curved surface?

Thanks!

[tedg]

So I have a curved roof I want to model some purlins on. They will be 2x4's laid flat. I don't want them to curve in plan - these will be straight members laid directly on top of the roof - they are not curved. The result will be a slight bend in elevation of the members as they attach to the roof.

Does anyone have any suggestions on how to go about modeling these? The beam family doesn't seem to be able to work in such a fashion. Can I make a face-based family that will attach to the curved surface?

Thanks!

I'm not sure if I totally understand, but you can use "structural framing" / wood / 2x4's and rotate the cross section 90 degrees (so they are laying on the flat side) and set the end elevations separately.
That's how I would do it based on your description of what you want to do.

[Peter1232]

I'm not sure if I totally understand, but you can use "structural framing" / wood / 2x4's and rotate the cross section 90 degrees (so they are laying on the flat side) and set the end elevations separately.
That's how I would do it based on your description of what you want to do.

The issue is the surface of the roof is curved -- making it sort of concave. So in the field the 2x4's will have to be bent to match the profile of the roof - they will be curved in the vertical direction. If I just modeled a 2x4 as structural framing, it is going to be elevated off of the roof in the middle.

[tedg]

The issue is the surface of the roof is curved -- making it sort of concave. So in the field the 2x4's will have to be bent to match the profile of the roof - they will be curved in the vertical direction. If I just modeled a 2x4 as structural framing, it is going to be elevated off of the roof in the middle.

Oh, I thought you DIDN'T want them to be curved based on your first post, that was what confused me:

They will be 2x4's laid flat. I don't want them to curve in plan - these will be straight members laid directly on top of the roof - they are not curved.

You want them straight in plan, but bent in elevation on a round surface..
Sorry, I don't have an answer for you.

[CAtDiva]

Consider creating your own beam family (or copy/modify an existing family). The basic structural families are profiles along a sweep path. The sweep path does not have to be a straight line, but could be a curve instead so that you get the curve in the vertical direction. In order to make the curve adjustable in plan, you will want a curved reference line with a radius (or other appropriate parameter) to adjust it. There will still be a symbolic representation in plan that looks straight.

As an example, I took the OOTB Dimension Lumber family and just added an arc reference line, assigned a radius parameter, and changed the sweep path to follow that reference line: https://www.dropbox.com/s/pkyygkb070zhsgb/Curved%20Lumber.rfa?dl=0. This one curves in plan, but using these concepts, you can create one that curves in elevation instead.