# Lofting a cricle to a non-parallalogram then trying to shell - which fails

**URL:** <https://discourse.shapr3d.com/t/lofting-a-cricle-to-a-non-parallalogram-then-trying-to-shell-which-fails/42310>\
**Category:** Modeling Questions\
**Created:** [October 15, 2026, 9:00pm UTC](https://discourse.shapr3d.com/t/lofting-a-cricle-to-a-non-parallalogram-then-trying-to-shell-which-fails/42310 "2026-10-15T21:00:45Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![tech1](https://avatars.discourse-cdn.com/v4/letter/t/4bbf92/32.png) [@tech1](https://discourse.shapr3d.com/u/tech1)\
**Post date:** [October 15, 2026, 9:00pm UTC](https://discourse.shapr3d.com/t/lofting-a-cricle-to-a-non-parallalogram-then-trying-to-shell-which-fails/42310/1 "2026-10-15T21:00:45Z")

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Hi there…I have another stumbling block.

I have attached the file that has a simple cylinder created by lofting two circles and then doing a simple shell.

I am trying to do this on a circle and non-parallelogram (close to rectangle). The loft works, but I am not able to get it to do the shell properly (or not at all). I have tried changing the shape a bit etc, change several features on the rectangular sketch but nothing allows me to get the shell to work.  
For some reason it’s not letting me select the 2 faces I want to loft (bottom face and the circle face). It’s as if they are not there.

The shell command does not show itself by default either, I have to select shell, then try to select the faces. The cylinder allowed me to select the 2 circles, then the shell tool and viola…worked as expected.

[naca\_duct\_dual\_1.shapr](https://discourse.shapr3d.com/uploads/short-url/tK4NmTQOPYL2DXFqLc5TIrtAslh.shapr) (831.5 KB)

 ![shell_fail](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/a/4/a49ce39a24e2bbc15098ab661ff4aa77efa4f8c9.png)

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**Author:** ![Xdrakosha](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/xdrakosha/32/24881_2.png) [@Xdrakosha](https://discourse.shapr3d.com/u/Xdrakosha)\
**Post date:** [October 15, 2026, 9:16pm UTC](https://discourse.shapr3d.com/t/lofting-a-cricle-to-a-non-parallalogram-then-trying-to-shell-which-fails/42310/2 "2026-10-15T21:16:50Z")

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<div class="post-metadata">

**Author:** ![tech1](https://avatars.discourse-cdn.com/v4/letter/t/4bbf92/32.png) [@tech1](https://discourse.shapr3d.com/u/tech1)\
**Post date:** [October 16, 2026, 3:18pm UTC](https://discourse.shapr3d.com/t/lofting-a-cricle-to-a-non-parallalogram-then-trying-to-shell-which-fails/42310/3 "2026-10-16T15:18:48Z")

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Thank you very much for the video…wow. It is that simple. I’ll give it a try.

Thanks. You guys are awesome out here.

I see what I didn’t do…i have to be careful what is visible and active so that I do not click on the wrong thing while trying some tools. I am using a mouse and Windows 11…a touch screen would be awesome (or tablet).

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**Author:** ![Oregonerd](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/oregonerd/32/8012_2.png) [@Oregonerd](https://discourse.shapr3d.com/u/Oregonerd)\
**Post date:** [October 16, 2026, 3:47pm UTC](https://discourse.shapr3d.com/t/lofting-a-cricle-to-a-non-parallalogram-then-trying-to-shell-which-fails/42310/4 "2026-10-16T15:47:14Z")

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I use an Asus Vivobook. A 16" laptop that folds like a tablet. Shapr works great on it for most designs.

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**Author:** ![tech1](https://avatars.discourse-cdn.com/v4/letter/t/4bbf92/32.png) [@tech1](https://discourse.shapr3d.com/u/tech1)\
**Post date:** [October 16, 2026, 5:24pm UTC](https://discourse.shapr3d.com/t/lofting-a-cricle-to-a-non-parallalogram-then-trying-to-shell-which-fails/42310/5 "2026-10-16T17:24:17Z")

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Nice.

Got a secondary question if i may. I want to do a similar item as the duct but with 2 outlets. It’s allowing me to loft the 2 circles to a rectangle (just for testing), but will not allow the shell. It complains about the bottom face (rectangle).

I gather there are several possibilities…make 2 bodies with single ducts, then remove the portions I don’t want and try to union them. Does that sound reasonable??

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**Author:** ![Xdrakosha](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/xdrakosha/32/24881_2.png) [@Xdrakosha](https://discourse.shapr3d.com/u/Xdrakosha)\
**Post date:** [October 16, 2026, 5:51pm UTC](https://discourse.shapr3d.com/t/lofting-a-cricle-to-a-non-parallalogram-then-trying-to-shell-which-fails/42310/6 "2026-10-16T17:51:29Z")

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It’s hard to fully understand what you’re trying to achieve from the description alone. It would be helpful to see at least a screenshot, or even better, a video.

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<div class="post-metadata">

**Author:** ![tech1](https://avatars.discourse-cdn.com/v4/letter/t/4bbf92/32.png) [@tech1](https://discourse.shapr3d.com/u/tech1)\
**Post date:** [October 16, 2026, 6:38pm UTC](https://discourse.shapr3d.com/t/lofting-a-cricle-to-a-non-parallalogram-then-trying-to-shell-which-fails/42310/7 "2026-10-16T18:38:05Z")

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Ya..sorry about that. This is just a test not the real shape of the bottom (rectangular section).

I’m also unable to smooth out outside. the loft and chamfer is kinda strange.

 ![naca_dual](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/0/3/034698ea0be08a62a15fe90f5562d65c5bf75307.png)

Trying to recreate something like this…

 ![images](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/0/4/04c5f0e96edb09cdf57d45896f9949d42a590994.jpeg)

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<div class="post-metadata">

**Author:** ![Xdrakosha](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/xdrakosha/32/24881_2.png) [@Xdrakosha](https://discourse.shapr3d.com/u/Xdrakosha)\
**Post date:** [October 16, 2026, 7:07pm UTC](https://discourse.shapr3d.com/t/lofting-a-cricle-to-a-non-parallalogram-then-trying-to-shell-which-fails/42310/8 "2026-10-16T19:07:46Z")

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Well, I think correct sketching is the key to success.

This also just a quick test not a finished result.

![test](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/3/9/3910280ad6c3b263a0637eb67030720a1443ba2a.gif)

[Test.step](https://discourse.shapr3d.com/uploads/short-url/nhQalW6ETRzzF6znhGivYYZFW4x.step) (2.2 MB)

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<div class="post-metadata">

**Author:** ![tech1](https://avatars.discourse-cdn.com/v4/letter/t/4bbf92/32.png) [@tech1](https://discourse.shapr3d.com/u/tech1)\
**Post date:** [October 16, 2026, 9:42pm UTC](https://discourse.shapr3d.com/t/lofting-a-cricle-to-a-non-parallalogram-then-trying-to-shell-which-fails/42310/9 "2026-10-16T21:42:48Z")

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Very nice…I’ll take a look. Great starting point. Thank you so much. I like you you did the mirror…I didn’t consider that.