# Complexe shape

**URL:** <https://discourse.shapr3d.com/t/complexe-shape/40718>\
**Category:** Modeling Questions\
**Created:** [April 27, 2026, 4:03pm UTC](https://discourse.shapr3d.com/t/complexe-shape/40718 "2026-04-27T16:03:42Z")\
**Posts on this page:** 20\
**Page:** 1

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**Author:** ![Tonio](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Tonio](https://discourse.shapr3d.com/u/Tonio)\
**Post date:** [April 27, 2026, 4:03pm UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/1 "2026-04-27T16:03:42Z")

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I struggle designing this backrest of a chair. Can someone help me how to sketch it ?

Thank you in advance!

 ![2](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/9/4/946d08c1ae56b79dce10bb627b26649280e410f5.png)

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**Author:** ![Tonio](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Tonio](https://discourse.shapr3d.com/u/Tonio)\
**Post date:** [April 27, 2026, 4:04pm UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/2 "2026-04-27T16:04:16Z")

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![3](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/a/1/a124362030a8eed8a1983151701b5e2c2eec31fc.png)

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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:** [April 27, 2026, 4:24pm UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/3 "2026-04-27T16:24:51Z")

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Looks okay to me. What are you trying to achieve? What do you want to be different about it?

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**Author:** ![Tonio](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Tonio](https://discourse.shapr3d.com/u/Tonio)\
**Post date:** [April 27, 2026, 5:47pm UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/4 "2026-04-27T17:47:45Z")

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This is a STEP from solid works that I opened in Shapr3D but for the CNC machining I need to redesign it.

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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:** [April 27, 2026, 8:32pm UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/5 "2026-04-27T20:32:36Z")

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Adjust to your sizes and forms

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**Author:** ![Tonio](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Tonio](https://discourse.shapr3d.com/u/Tonio)\
**Post date:** [April 29, 2026, 5:24am UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/6 "2026-04-29T05:24:35Z")

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thank you for your help and the video! The curve is a bit more complicated I send an additional picture. When you look at the first picture I sent the upper edges are at a 90 degre angle to the curved top.

 ![1](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/7/8/7875b1d8fc0ff13e73fcc521e0f3b5f9ff35f6d8.png)

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**Author:** ![Tonio](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Tonio](https://discourse.shapr3d.com/u/Tonio)\
**Post date:** [April 29, 2026, 5:26am UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/7 "2026-04-29T05:26:15Z")

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![4](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/f/c/fc68249910a6027582df5b6e6df719bf026e7ec4.png)

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**Author:** ![TigerMike](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tigermike/32/32650_2.png) [@TigerMike](https://discourse.shapr3d.com/u/TigerMike)\
**Post date:** [April 29, 2026, 5:59am UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/8 "2026-04-29T05:59:07Z")

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Does this approach work for you?

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**Author:** ![Tonio](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Tonio](https://discourse.shapr3d.com/u/Tonio)\
**Post date:** [April 29, 2026, 6:24am UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/9 "2026-04-29T06:24:53Z")

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thank you. I send more detailed picture. the upper edge in your sketch is not at a 90 degree angle .

 ![5+](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/6/a/6aee62b99f992b5075cbf1a80ba7fef8bcffbabb.jpeg)

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**Author:** ![Tonio](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Tonio](https://discourse.shapr3d.com/u/Tonio)\
**Post date:** [April 29, 2026, 6:25am UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/10 "2026-04-29T06:25:27Z")

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![7](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/a/3/a3bd10b79ef5b39f71eec68e0a6e45cf6972d12c.jpeg)

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**Author:** ![Tonio](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Tonio](https://discourse.shapr3d.com/u/Tonio)\
**Post date:** [April 29, 2026, 6:26am UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/11 "2026-04-29T06:26:02Z")

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![6](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/4/a/4a8c9168f5dd1e665a75b5a842c9d31baa3a1c9a.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:** [April 29, 2026, 7:04am UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/12 "2026-04-29T07:04:44Z")

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Just send a step file you have. That will tell more the a thousands of photos.

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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:** [April 29, 2026, 7:47am UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/13 "2026-04-29T07:47:50Z")

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> [@Tonio](#):
>
> the upper edges are at a 90 degre angle to the curved top.

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/b/5/b5630106b73f6ba5acfa1eb936ce2be27284653f.png)

?

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<div class="post-metadata">

**Author:** ![Tonio](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Tonio](https://discourse.shapr3d.com/u/Tonio)\
**Post date:** [April 29, 2026, 9:01am UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/14 "2026-04-29T09:01:55Z")

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yes this looks better! I would like to send a STEP but I get the message that new users cant’t send attachements

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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:** [April 29, 2026, 10:44am UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/15 "2026-04-29T10:44:58Z")

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> [@Tonio](#):
>
> I would like to send a STEP

You can send it to [shapr3d@tsbl.net](mailto:shapr3d@tsbl.net)

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<div class="post-metadata">

**Author:** ![TigerMike](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tigermike/32/32650_2.png) [@TigerMike](https://discourse.shapr3d.com/u/TigerMike)\
**Post date:** [April 29, 2026, 2:08pm UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/16 "2026-04-29T14:08:27Z")

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Are the upper and lower inner arcs the same radius?

It appears to me that the upper arc has a larger radius.

 ![chair](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/f/a/fa5336b4e978cd8582f72c989325d5b70e2f94b8.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:** [April 29, 2026, 4:42pm UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/17 "2026-04-29T16:42:54Z")

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Sizes not 100% accurate.

[![](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/b/5/b531015217eda972772243508d77dce0e7023cbe.jpeg "Another demo") ](https://www.youtube.com/watch?v=YrfrbDjRWeY)

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<div class="post-metadata">

**Author:** ![Tonio](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Tonio](https://discourse.shapr3d.com/u/Tonio)\
**Post date:** [April 29, 2026, 8:19pm UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/18 "2026-04-29T20:19:23Z")

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Awesome thank you! very interesting.

Would you start with the general form and then start to design the risers on each side with the angled assembly?

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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:** [April 29, 2026, 8:28pm UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/19 "2026-04-29T20:28:13Z")

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> [@Tonio](#):
>
> Would you start with the general form and then start to design the risers on each side with the angled assembly?

I’m not entirely sure what you’re asking. I’ve already shown how to design the element in question, and there’s nothing more to add. If you’re referring to something else, please show or describe the new geometry.

* * *

Looks like I understand what you’re asking about.

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/1/6/16987e07dd2bdda98b47ecc2fc3580fb121988cb.png)

You need to make this colorful things 🙂 And yes, I would make general form first and then start working on that additional parts.

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<div class="post-metadata">

**Author:** ![Tonio](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Tonio](https://discourse.shapr3d.com/u/Tonio)\
**Post date:** [April 30, 2026, 1:09pm UTC](https://discourse.shapr3d.com/t/complexe-shape/40718/20 "2026-04-30T13:09:51Z")

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Yes exactly, the green, blue and pink piece. So you would make the angeled cut on the general shape with the sweep tool and then ? sketch the shape of the blue/green piece and project it to extrude it?

[Next page](https://discourse.shapr3d.com/t/complexe-shape/40718.md?page=2)