Perforations in a curved wall

Hi all, I have been struggling with a certain operation in my model and have a few related questions so will post them all here, apologies for the length. I have tried to find similar posted topics, but can’t seem to find an answer. I am using SU 2017 and am a novice. The models attached are small portions of a bigger project to get the files under 5mb. My main file is 90MB now and I have purged it several times. The geometry is pretty simple I think but I assume the components from warehouse are contributing to the file size.

I am trying to cut many small equally sized and spaced holes in a curved walls. I refer to it as perforations due to their frequency. I have attempted a few methods and am still having open face issues and other weird geometry occurring. I have attached two models: in “file-1” I have extruded vertically the solid sections of wall and then copied and dragged the adjacent section of horizontal face vertically upwards to create the perforation, then extruded that face to create the wall above, and then repeated this process. It is very time consuming though and I can’t seem to make a component to repeat as the curve is composed of sections that differ as the arc progresses, never mind the opposite side of the circular form.

In the second file, I attempted to make a component out of a horizontal band or section of these perforations with the idea that I would copy and paste this vertically to expedite the process, but I am not having success at closing geometry, or when I go to clean up lines, faces randomly disappear.

In the first file, the newly extruded wall sections have white faces as opposed to the grey, and lines appear on the inside face of the circular form. They can be erased with seemingly no issue, but just curious why they are appearing in the first place.

Also is there an easier way to copy and drag an object within a certain axis orientation. I am using the move tool, option and the up arrow bar, then typing in the desired vertical dimension.

What would be the best way to place glass in the openings, I drew a line mid depth in the thickness of the perforation and then add vertical lines to create a face that I would then paint with some texture (in this case glass block). Ideally this would be a component so I can play around with different colours or materials.

I did increase the segments of the circular shape to 48 from the default 24. I have read that most experienced users prefer less segments, but it is visually easier for me to work with a smoother curve. Any thoughts on that also.

file-1.skp (406.8 KB)

file-2.skp (386.3 KB)

Thanks in advance.

Generally for a thing like that, I would model only a section of it and then use Rotate/Copy to make the rest.

One thing you should do first is get rid of the texture (same texturing for after the modeling is complete) and make sure the face orientation is correct. Most of the faces in your model are reversed showing the blue back faces out.

You would also find it easier to model something like this if you center it on the origin.

How are you determining the widths of the openings?

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Hmm not sure what you mean about just using rotate/ copy. Yes I was going to remove the texture, but the course lines of the CMU block establish the perforations for the glass block, so that is why Ieft it. t seems the blue/gray (reverse surface) tends to default on most objects I make.

The widths of the openings are 8" (standard glass block). and the adjacent solid are 16" (standard CMU). I am taking a width at the inner face of the curve for the CMU, and in the middle for the glass block, as that is how I would draw it and build it.

If you are OK with the length of the sections of the circle being so large, I’d try adjusting the number of side of the circle to match the window openings so that you are essentially doing the windows in a flat face–though by softening the wall vertical lines it will appear as smooth cylinder. But Dave’s idea makes a a lot of sense and could save a lot of work. If the windows are likely to be flat glass, make one component that fits in the opening and duplicate it up the wall, make a component of the vertical array and then duplicate copy radially as Dave recommends.

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The Rotate tool has a copy function when you hit option. You can copy geometry around the center of the circle using it so you don’t have to model repeated details.

This is due to the way you are going from 2D to 3D. It doesn’t have to be that way, though.

Again, how are you determining the spacing of the openings?

Here I’ve started to redraw your model. I made the pipe 3D before I added the large openings at the bottom

Peter makes a good point. Use a number of segments for the circles that is divisible byt the number of small openings. That will result in cleaner geometry and make it easier to model.


Again, how are you determining the spacing of the openings?


The widths of the openings are 8" (standard glass block), and the adjacent solid are 16" (standard CMU). I am using the measuring tape to establish the 8" width in the center of the curved wall, then use a guideline from the center of the circle to keep the openings consistent with the radius, if that makes any sense.

Okay, so I can increase the segments without an issue? I thought I was pushing it by going to 48…

Yes the windows will be flat glassblock or possibly stained panes. If I make a component, I still have to place them into each opening manually, no?

You can increase the number of segments but don’t go crazy. Since this thing is going to be built out of 8" wide blocks, you could adjust the size so the sides are 8 in. on the inside.

The diameter of this form is 26’, so it would have to be many segments, but I will try and appreciate the responses.

96 sides at 8 in. long makes the inside about 20’ 4-12" in diameter.

I try to keep the number of sides divisible by 12 if I can.

With 120 sides at 8 in. long, the diameter would be about 25 5-5/8".

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One way to do as Dave suggests is to draw the circle with sides equal to the number of 8" blocks proposed. Then scale the whole model (circle at this point) using the tape tool. It’s a particular stnadard technique. I have to leave, so I can’t go over it.

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Is this reasonably close to what you have in mind?

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Yes, that is it. Fantanstic! I won’t even to begin to tell you how much time I have spent on this.
I hear what you say about centering the circle on the origin, but I have two square forms that intersect with this one, and to redo it would be a lot of work…I learn as I go unfortunately. Is there a way to move everything to a new origin. Also If I redo this form with multiple segments as you and Peter have suggested, I still will have an issue of it meeting with it’s adjacent forms that are the same external diameter but still at 48 segments. My explanation is confusing I suspect…

For the actual glass blocks, would you use a component and place them individually? Or rather, I guess this is made form repetitive geometry, so the blocks would be placed in the component before repeating.

What am I doing wrong here?

You could move your existing model so it is centered on the origin. Locate the center of it at the base by placing crossing guidelines or right click on one of the bottom arcs and select Find Center (I disremember when that second option was introduced as a feature. Been a lot of water under the bridge since SU2017.) Then select all of the model, get the move tool and click on the center point. Start moving the geometry, let go of the mouse and type [0,0,0] with the square brackets. Hit Enter.

A little. I think your model needs enough fixing that for this part at least, I’d be inclined to start. Sometimes that easier than trying to repair what you’ve got. It’s your model so it’s your call, though.

If I needed to show the individual blocks or get a count of how many would be needed, I would make a glass block component and copy it around and up to make the structure. A benefit of this method is you can build the wall up and then just delete the blocks you don’t want.

The reason you get the reversed faces is you are drawing out all your lines on a 2D shape and then extruding just some of them. Instead, extrude the shape to make it 3D and then add the lines to divide the faces. Hang tight. I’ll make an example of you. I mean for you.

On the left, I drew the circles and then the lines defining the breaks before extruding sections and the faces wind up inside out. On the right, I started with the same circles but extruded the pipe before outlining the breaks on the bottom and pushing faces up to make the openings.

It seems to be a common thing with new users. They start out thinking and laying out the lines for their project in 2D before switching to 3D thinking. We see it frequently with floor plans going to 3D building models and things being model for 3D printing such as little project boxes. You can fix reversed faces when they occur but most often, a little change in the workflow will prevent them from happening in the first place.

Thanks for your time explaining this, much appreciated. I will attempt to move the model to the origin and if I run into issues I’ll start from scratch again…gulp. I’ve attached a screenshot of the larger project to give you context. I am playing with different fenestration options, hence the perforated screen facade.

I think my issue is I had to line up where the orthagonal walls of the other volumes intersected with the cylinder, therefore I was extending lines onto the flat face prior to extruding. What are the larger issues of reversed faces, why does it matter. SOrry probably an obvious question.

Ah… I see. At least while you are playing around with shapes, it’s a good idea to keep things separate and not allow portions of the project to permanently affect other parts. For example, if you trimmed the square sections to meet the cylinder, I would suggest not doing that until the cylinder is set in glass. (see what I did there?)

Another thing to consider, though is limiting the amount of details in your sections of model and making sure you group geometry so that it can’t interact with other geometry.

Reversed faces can be a problem when applying textures and some rendering programs won’t render back faces at all, even if they have textures applied. There are also issues for certain things like 3D printing. In general it is best to keep your models as clean as possible including correct face orientation. It makes them easier to work on when changes come along.

Out of curiosity, is this a house you are going to build or just a dream?