Rotating around an arc

I’m drawing the bima for the synagogue that I work for. The bima is a fan shaped semi circle and components of the bima are offset from one another. In the screenshot, the parts marked A are ramps. However, I’m at a loss as to how to rotate those components around the arc. When I do a standard rotate, I can get one side at the proper height, but the bottom of the ramp is misaligned and and not coplanar. I imagine this is an extension I’ll have to download but I’m not finding anything. Any thoughts?

Here’s the file, just in case.

Arkfrontfloor~.skp (159.9 KB)

What axis exactly and how much do you want to rotate? Can you give more information?

Forgive me as I’m not super sketchup savvy. But if you look at the surface on the left marked A, the right side of the surface is at the proper height. I need to rotate the surface downward along the horizontal axis, with the right side as the anchor, so that the left side is on the base. However, it seems I need to rotate it simultaneously along the z and y axis so that the shape both hugs the circle and remains on the z axis. I’m not sure how to do that without an extension.

So the right side of surface A is at 13.75" and the left side of surface A should be at 0".

Something like this?

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exactly like that. How did you do that?

“Move Tool”

As simple as that? So you just grabbed that edge and moved it down 13.75"

Yep. Simple as that. Duh.

Yes! That’s exactly what I did.

Before you get too far. Please, do not work with the default setting of the segments number in arcs and circles. At large sizes, your bows look too angular. And the method shown by @ecati slightly deforms the adjacent geometry. You will see this by turning on the display of invisible geometry. But in this case, it doesn’t really matter much.

I’ll remember that in the future. For this project, I’m drawing this segment of the sanctuary in SK because of the large number of surfaces that need to be extruded. The entire project is in Vectorworks. When I export this part of it to VW, I believe that VW smoothes the arc segments so it doesn’t look so angular.

Sturnus is right. That method works pretty well in some instances to give a representation of the ramp. However it’s not accurate if that’s what you are after. When you move the end of an arc like that it distorts the arc in the x,y dimension. You can see that in how the side walls no longer have simple vertical faces. Fredo’s Curvishear plugin solves this.

Also for this move-down method, using TIG’s Split Sausage plugin on the ramp face beforehand will give cleaner geometry. (You have to soften the edges made by the plugin, and turn off Show Hidden geometry before you make the move)

But it looks fine in this case. Just not technically accurate.

Have you tried this yet?

One simple method to make a ramp is to intersect the two shapes, in this case it is easy to do it within one block. Determine the angle and the curve and pushed them through each other.
Simple ramp

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A proper curved ramp for walking on has 0 slope perpendicular to the path of travel (within tolerances). The slope in the direction of travel along the arc is constant.