Is there a way to use follow me up an arc at an angle?



RiverArch 5.skp (2.0 MB)
I am trying to use follow me (or, alternately, Component Stringer) to create an arch but with sides that taper toward the top by 12 degrees on each side (see attachment) towards each other at the top. Is that a way to do that? Follow me thinks it is “not a valid path” and component stringer can’t handle it either.


Draw the cross section you want as a face on the red-green plane, starting at the end of one arch.

Select ONE of the arcs with the Select tool, and leave it highlighted.

Select the FollowMe tool

Click on the cross section face.

That should do it.

Too late to show you tonight, but may have a chance to do an animated GIF and/or Skype you tomorrow.

Here’s an example:

Arch with tapered cross-section.skp (36.7 KB)

EDIT. I see I misunderstood. You want something more like this.

Do as above, then select the sides of the arch one at a time, and rotate them inwards by the angle you want: like this.

Arch with tapered cross-section.skp (40.9 KB)


RiverArch 5.skp (2.2 MB)

Yes, the second example is closer to what I want, but when I tried it, it kept fracturing the bottom plane of the legs. I thought it might be the remnants of the track on one side, so I rotated the other side first, but the same thing happened. Then I thought it might be the channel, but even when I pulled out the channel so it was flat with the vertical plane of the arch, it still fractured (well, I suppose I might have been slightly off in lining it up). Sometimes it fractured the base of one leg but not the other.
What to do?
Ignore the tracks. I’ll have to delete those, but one segment at a time apparently, since it is not a single component. In any case, I’ll be using a modified version of my new elevator, not the old cog elevator which wouldn’t work on a tilted arch.


Could we have a skype conversation either shortly, this morning (UK time) or from mid-afternoon onwards?

What are the exact dimensions of the floor plan? 800’ x 250’??. What you have isn’t exactly on the origin, nor exactly in the X-Y plane, I think. And the far end of one of your arches also isn’t at Z=0.

And the radius of the outer arch? (Alternatively, the diameter to reach the ‘opposite bank’)? It looks to be approximately 1930’D - but also isn’t exactly that.


I attach the best I could manage this morning.

Started with a floor exactly 800’x250’, then notched out the corners by 21’x12’6.

Drew a full circle 1930’ diam, and another inside it 500’ smaller, to line up with edges of floor, each with 360 segments. Deleted outer circle - probably didn’t really need it.

Rotated the inner circle 0.5 degrees, to get the midpoint of end segments on the red axis.

Drew a line across the diameter, then deleted bottom half of the inner circle. Deleted the diameter, leaving just a semicircular arc.

Selected the arc. Started FollowMe tool, and picked the floor.

This slightly lifts the outer edge of the floor off the X-Y plane, so I rotated the floor at each end 0.5 degrees back down into plane, rotating about the inner edge of the floor. Not sure why this happened, as I thought the rotation of the circle would get the outer half-segment vertical - something a little odd here.

Then rotated the outside flat faces of the semicircular ‘tube’ inwards by 12 deg about the red direction.


Arch v6.skp (235.2 KB)

If you actually want the inner part of the arch to have a bigger diameter, resembling your original skeletal arcs, I don’t know how that’s going to work for the elevator - if inner and outer arcs aren’t concentric. Not even really sure how this one will work, either.


To get where you want to be start from a different place !


Not sure I understand the alternate way, but I’ve decided I will abandon the lattice work and cog elevator/tram. Yes, even after all that work! Better to get it right and good than continue on with a flawed approach. And I am well underway with a new elevator design that rotates in two outer rings and for the outside it will pivot up to 12 degrees as well.

Yes, I do want the arch to taper at the top to half the width of the legs at the bottom. I realized when I was doing the arch the old way that on the 72 floor where the legs finally merge, there would be over 100,000 square feet of space. While that’s great for warehouse and multiple football fields, people do not want to live in a warehouse. Also, the new way solves a problem I’ve had from the beginning of blocking the sunlight from people who face inward inside the arch. There’s going to be another architectural feature once the basic design is done, but that comes first.

Going back to it now…


Also, the 2 elevators on the south side only have to start at ground and then meet just short of the halfway point on top to discharge their passengers so no stops in between. The elevator on the north side is a single one going from the base of one leg to the base of the other leg so again only 2 stops.
Are you there? I am trying to get this and also the inside elevator now. Thanks for all your help…but I need more :frowning:


not sure I fully understand, but would be happy to talk on Skype for a while - free now for about an hour, or later this evening


calling in now…


Here’s arch v7 as we discussed.
Arch v7.skp (479.1 KB)


Arch 7.skp (175.2 KB)
I just learned about the ability to use Google Earth and Google maps to more precisely map out my location, and now I see my measurements were off by 70’ (in round numbers). This means I have to increase the span of my arch to 1500’, which is a nice even number, but I can’t seem to get a face with which to do the lean in (probably more like 10 degrees now with the larger arch instead of 12 degrees). See upload and also Arch v7.skp for the general shape. The inner arc should be now 875’ high, and the outer one an even 1000’ high, and the tapering should narrow it to 400’ at the top form 800’ wide footprints. I was so careful and let it snap into place so I don’t know why I can’t get faces.


Your main problem is that model isn’t correctly structured yet.

First make one of the floors into a component, delete the other floor, then copy or (better) mirror the first one to get the second.

Second, your inner and outer arches are separate components. You can’t create a face between lines and arcs in different components.

Explode the arches, and draw or redraw lines between the bottoms of the inner and outer arches to create a face. Make the face into a component. Open the component for editing, then pushpull to create a solid arch.

Then lean it in - select each face in turn, and rotate about red to bring the tops 400’ apart. You might need to do a little calculation to get the correct angle, or you could try drawing vertical faces or a block 400’ wide as a component on the centreline, and rotating to meet its outside faces.

If you haven’t already installed it, get the TIG Mirror plugin from

Best wishes.


Arch 7.skp (462.0 KB)
Here is the latest attempt. It looks close superficially, but there are damaged floors. We had this problem before, but I don’t remember what we did to get the external channels right without fracturing the floors. I may have to start over. Fighting a cold now and I’ve been on this all day, so I will come back to this later.

I tried to find Tig Mirror but it wasn’t among the 17 matches in the Extension warehouse. I did download solid inspector, but didn’t know how to install it. It’s an .rbz file.

Well, at least I’m learning how to use Google maps/Earth with SU. This video is indispensable:


Sorry you have a cold - feels miserable.

Work inside the arch component to avoid ‘fracturing the floors’ when editing. And even if you get a shadow or hidden line across them , if you can delete it without losing the face, the floor is still flat.

You can access the Extension Warehouse from within SU, and install automatically from that (recommended).

Or install an rbz download using menu Window/Extension Manager/Install Extension (in SU 2017 only) or via Sketchup/Preferences/Extensions/Install Extension (on Mac) or Window/Preferences… (on Windows) for SU 8M2 - SU 2016.

TIG Mirror is on the Sketchucation Plugin Store, not Extension Warehouse.


Arch 8.skp (285.7 KB)
The problem I’m having is with the two 12’ X 21’ inside channels for the tram/elevators to go into. If I cut them before I tilt in the arch sides, it distorts the floor. And if I try to draw an arc on the face after I tilt them in (much harder!) I can’t pushpull the channel in 21’ because SU thinks it’s a curved surface. I know we figured out a way around this before but can’t figure out the steps now. Everything else is pretty easy now.
What to do?


I could give you a Skype call in 10-15 mins from now if that would help?


Yup. I’m here. :slight_smile:


I’ll call as soon as I’m free, soon


Can you show or upload an example of the cut with the tram installed? This way we can understand all the variables you are working with.