# Thread: Edit a revolve

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## Edit a revolve

I have a precast concrete family created using a revolve. It is a 30 degree segment of a circle. 12 of these put together make the circle. Beautiful as it is, I need some of the lines to be straight instead of arcs. Is there a way to edit the revolve and replace some of the arcs with straight line segments? The result would make part of the revolve a twelve sided polygon instead of a true circle.

[Attached is jpg. I think you can understand that part of this shape is a trench drain. The designer wants it to be a straight line segment instead of a true circle]

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## Re: Edit a revolve

No. A revolve solid will always create volumes with round surfaces, since in essence it is the revolution of a closed 2D shape around an axis.

However, you can achieve the desired result by using the same 2D shape as a profile for a Swept solid instead, with a polygon as the path.

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## Re: Edit a revolve

You could probably do o sweep instead of the revolve then you can have whatever straight lines you want. I don't believe there is a way to do it with a revolve.

You may have to leave like a 1/64" gap at the end of the sweep to keep from making a closed loop but should get you pretty close.

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## Re: Edit a revolve

You can impose a solid or void on the revolve to get your straight lines.

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## Re: Edit a revolve

Originally Posted by UpNorth
You can impose a solid or void on the revolve to get your straight lines.

I was just about to explore that line of thought. What I didn't mention in the original post is that the outer circle has to be circular to define the form, but the inner "circles" need to be linear segments for budget reasons. We are considering limestone instead of precast and curved stonework is \$\$\$\$\$\$\$. Ultimately we will have a mix of true curves and segmented curves in the final design.

Could I make a revolved family for just the outer edges, creating a big "mass" of stone, then run a straight void sweep through the "mass" creating the straight elements? I assume I would have to nest the first family into a second family to do the void sweep.

This is the base to a design that the designers are quoting from the Florence Duomo. Above this are several colonnades topped by a dome and lantern. It's one of the most challenging models I've attempted so far.....

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## Re: Edit a revolve

If you create your revolve, in the same family you could then create a void. The void can be a revolve or a perpendicular extrusion - depending on the exact need.

Edit: well the void could be a revolve, but you would not get straight edges. I think the perpendicular extrusion is your best bet.

Sounds like a fun project!

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## Re: Edit a revolve

Revolve the curved forms... sweep the straight segmented part along a path and then join the two surfaces.

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## Re: Edit a revolve

Got it!!!! The solution was NOT to nest the families, but to add the void directly to the revolve as an extrusion.

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## Re: Edit a revolve

Hi Mike -

If you create the avoid and use Trajectory Segmentation (it an Instance Parameter) a value of 0 will be a smooth circle - but values of three or greater should segment the void into straight segments.

Hope all's well!

Phil

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## Re: Edit a revolve

Originally Posted by Phil Read
Hi Mike -

If you create the avoid and use Trajectory Segmentation (it an Instance Parameter) a value of 0 will be a smooth circle - but values of three or greater should segment the void into straight segments.

Hope all's well!

Phil
Thanks Phil.

BTW as you can see, I'm back in the saddle again.

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