Arch 7.skp (794.9 KB)
This is the latest with the channels cut in but not the sides slanted 11 degrees like Arch 8. It’s already damaged from all my playing around, but you can get the idea. I had an earlier version complete with cog-tram, but that won’t work on an angle, and I have a new tram-elevator anyway that runs on a single track going along the top while rotating inside two outer cylinders.
John Mcclenahan is about to Skype me anyway, so he’ll probably be able to walk me through this (again).
OK, I prepared my Arch 7 model for us as best I could.Arch 7.skp (665.1 KB)
As you can see, it distorts the floors about 4’ whenever I tilt in the sides 11 degrees. I tried pushpull, move etc. but it all makes things worse.
Here’s the arch with the side cutouts, as we did together.
Arch 8a.skp (560.0 KB)
Steps:
- Draw the arcs and ends for the arch
- Push pull to full depth (800’)
- Make into a component
- Open it for editing, then copy the inner arc, close the component, and paste in place in the model context. Move it away from the main arch.
- Find the centre of the top of the arc: to do that, draw a line up from the midpoint of the base of the arc.
- Draw another arc 12’ larger outside the inner arc. Join the arcs at the base with straight lines. That should create a face
- Push-pull the face 21’. Make a component of the result, to begin to make the cutout you want for the notch in the main arch.
- Determine the angle you want the sides of the main arch to slope in by - 11 degrees in this case - and slope the sides in by rotating each face inwards from the bottom, around the red axis, by that amount
- Draw a line upwards from the top of the inner arc sloping up across the cutout arch at 11 degrees from horizontal
- Open the cutout component for editing, select the inner face, and move it vetically (on blue axis) to meet the sloping line.
- Close the component, and rotate the whole cutout about red axis by 11 degrees
- Move it back to meet the main arch.
- Use Solid Tools/Trim to subtract the cutout shape from the main arch
- Mirror the cutout shape to the other side of tha arch, and use solid tools again to cut out the other side.
An alternative way to make this might be to use the Follow Me Upright plugin by Eneroth3. The native FollowMe tool tends to twist as it follows the tilted arc, and won’t make the clean end you need.
Just a thought on a different workflow using Fredo Scale…
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Does that keep the notched cutout with its short out-to-inside edges horizontal? In other words, does it perform in effect a shear operation rather than a rotation of the outer faces? If so, that’s a lot easier than what we just did.
By the way, the outer arc is semicircular, but the inner one is bigger than a semicircle, so the ‘thickness’ of the arch in-to-outside is smaller at the top than at the bottom. That would mean the FollowMe wouldn’t make the right shape, but even so, making the parallel sided arch with pushpull is easy. Following that with FredoScale would still work in the way you show.
Dimensions: inner opening 1500’ at bottom
Floor 250’ x 800’
Outer arc radius 1000’
Inner arc drawn with bulge of 875’ between the points 1500’ apart
@TheOnlyAaron - your method works on the arch that @NewThinking2 wants to have - here’s the result again
Arch 8b.skp (423.2 KB)
This should be identical to Arch 8a as far as I can tell.
PS. Except that this is exactly 400’ across at the top. The other was only approximate, with a side slope of 11°.
Woo hoo!
Glad to hear!!
Yes, I think I’ll use Archb then, for exactly 400’ across the top.
Thanks guys…
Arch 8b.skp (440.9 KB)
There is actually a different problem with this arch. The channel is not the same size all the way up; it narrows at the top.
The channel needs to be exactly 21’ wide by 12’ 6" deep or else the elevator won’t fit all the way.
The other dimensions are good, so is there a way to get the channel fixed without having to redo the rest?
Narrows sideways, vertically, or both?
The 21’ becomes about 11’. The 12.6 is off too, but consistently at 12’, which I can actually live with by burying part of the concrete mounting in the wall, of just having the elevator stick out a few inches past the inner arch wall.
Arch 8c.skp (2.6 MB)
Here is what happened when I tried to place the new elevator in an upper part of the outside channel. Ignore the track placement for now. The point is the width of the channel is too small.
Oop, no, it is shrinking in BOTH directions. Not good…
Thhe follow me tool has had issues over the years, profile twisting as ir follow the rail, then profile changing dimension as it followed the rail. I have not check it lately but, thought it was fixed.
However, your post shows some skewing that needs to be fxed and maybe correction of axis setting. The follow me tool has a limited degree of freedom and in wose case some other tool may be required. I’ll need to check more hopefully others have a better idea.
That’s odd. When I first drew Arch 8b with you, I used FredoScale to shear the tops inwards. Didn’t rotate the outside faces inwards. Didn’t use FollowMe at all, but an offset followed by PushPull while the arch sides were still vertical, then the shearing action. I don’t see why that would have scaled the depth or height of the channel.
Too late tonight to look, but will have a look at earlier attempt and try to see what happened and why.
Arch 8a.skp (564.1 KB)
Thanks.
Alternately, we could use your Archa (attached), but then we have to get the bottom of the arch exactly 875’ from the floor (I created a temporary floor to be able to measure from), and also make the peak of the arch just 400’ wide; it’s a bit wider now. The channel on that one seems OK, so maybe it’s easier to do it with this one?
Anyway, I’ll check back during my night shift, which should be your morning, or later if you have some time.
Meanwhile, I’m working on the elevator too and sent you a short email about that. I made progress but had a question about the window (I have to mirror it too) etc.
Thanks for all your help.
Arch Wireframe.skp (455.2 KB)
It turns out even the base floors were mismeasured at the cutouts, so I had to trim and add to them to make them exactly 21’ long by 12.5’ deep.
Also, the arch 8a and arch 8b both splayed outward in the inner arcs, instead of just being more ovoid instead of semi-circular (the outer arc, of course, is a true semi-circle). The inner and outer arcs are not concentric, so the arc tapers towards the top, as well as leans in and loses half the width at the base at the top, going from 800’ deep to 400’.
Then I just created arcs and used scale to adjust them to the correct heights - 875’ for the inside arc, 887.5’ for the arc from the cutouts set back, and finally 1000’ for the outer arcs.
But this still leaves me with no faces and no way to use pushpull to extrude to those height. I also won’t have those radius’ even if I could fill in the spaces and then lean in sides so that there is only 400’ across the top of the arch.
The closest example I can think of to what I’m doing is the St. Louis Gateway Arch, but without the downward pointing triangle shape, just flat on the bottom instead. And of course, it will have a lot more volume overall. I"m sure there is a way to do this in SU, just as there is for anything else.
Arch Wireframe.skp (463.3 KB)
I played around with this some more and was able to super meticulously get the wireframe to scale to exactly the right sizes enough to get two faces created. But there must be an easier way to do this!
Once all the faces are created, however, is it possible to use section cuts at an angle to slope the sides of the arch? Then I don’t have to worry about the height shrinking.
I’ve finally managed to get what I think you want.
I first drew one face of the arch, and pushpulled it 800’ to make a solid, parallel sided arch. Then drew an extra arc for the outside of the channel, and pushpulled it to make the channel, 12’6 deep and 21’ wide.
The hardest part was the next step, and it took several goes to get it right, which I think it now is.
I used the FredoScale tool, selected one face including the channel, and did a Box Shear to Target, to move the top inwards by 200’, and shear the face proportionately all the way down.
This produces a channel which is a uniform 12’6 deep and 21’ wide, on the slope.
Then I mirrored this sloped face to the opposite side, deleted the vertical face on that side, and after a bit of cleaning up, got this:
Arch 9.skp (217.7 KB)
I think this is pretty much what you wanted.
In retrospect, I think I could have avoided most of the cleanup, which was needed where the mirrored sloped face and channel intersected with the vertical face (and channel, which needn’t have been there, and interfered).
I should have moved that vertical face further, to keep it clear of the mirrored sloping face, and not channeled it at all. Then all that would have been needed would have been to select that whole vertical face and its connecting hidden line horizontals, and delete them - no further cleanup needed.
PS. And by the way, I drew the outside and inside circles for the arch using the Circle tool, rotated by half a segment, then deleted the lower part. That gets the first half-segment vertical, rather than on a 1° slope. It has the slight drawback of changing the circle to a Curve, not an Arc, but after the shearing operation the outer and inner edges are no longer circles anyway, but parts of ellipses. The outer edge is about 20’ further (at ~1020’ measured in the plane of the sloping face) from the former centre than the bottom edges are (the original 1000’) However, the outer FACE of the arch still has a circular cross section and the top centre is still 1000’ above the origin.
And you can see in this Front view, parallalel projection, that the inner face of the channel is displaced parallel to the green axis.
