# Solids from patterns and parametric changes

**URL:** <https://discourse.shapr3d.com/t/solids-from-patterns-and-parametric-changes/41282>\
**Category:** Modeling Questions\
**Created:** [July 20, 2026, 7:24pm UTC](https://discourse.shapr3d.com/t/solids-from-patterns-and-parametric-changes/41282 "2026-07-20T19:24:25Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Fawksey3D](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/fawksey3d/32/36063_2.png) [@Fawksey3D](https://discourse.shapr3d.com/u/Fawksey3D)\
**Post date:** [July 20, 2026, 7:24pm UTC](https://discourse.shapr3d.com/t/solids-from-patterns-and-parametric-changes/41282/1 "2026-07-20T19:24:25Z")

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Challenge 4 threw this up for me in terms of my understanding. Changing the setting so not to spoil the challenge.

I create a simple circular pattern of 3 circles. Use a variable for the number of circles. Then extrude. Great I have 3 cylinders.

 ![IMG_5531](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/b/4/b4b16e413d3cc06e8999c78d9287baec0df6b1af.jpeg)

I change the number variable to 5 and the cylinders change position but the additional 2 cylinders that now appear in the sketch do not get created. That’s fair enough i suppose.

 ![IMG_5532](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/b/4/b45945513f7300de290afb1e2afca7a68a4a8649.jpeg)

Now in reverse so to speak. If i create 5 solids first (from the 5 patterned circles). And the change the variable down from 5 to 3. The sketch readjusts and the 5 solids reduce to 3 - great. But…. I get an exception in the history for the missing solids.

 ![IMG_5533](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/7/8/78ef5c205dcd49e856878c9d62393c73792da8df.jpeg)

 ![IMG_5534](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/c/a/ca357884e549a221a4a9b9a97178e48f15289b16.jpeg)

I am guessing the is a way to tie solid generation to sketch variability without throwing exception.🤔 .

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**Author:** ![Fawksey3D](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/fawksey3d/32/36063_2.png) [@Fawksey3D](https://discourse.shapr3d.com/u/Fawksey3D)\
**Post date:** [July 22, 2026, 1:25pm UTC](https://discourse.shapr3d.com/t/solids-from-patterns-and-parametric-changes/41282/2 "2026-07-22T13:25:31Z")

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Sorry guys. Did anybody have any views on this?

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**Author:** ![DrKronos](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/drkronos/32/36064_2.png) [@DrKronos](https://discourse.shapr3d.com/u/DrKronos)\
**Post date:** [July 22, 2026, 1:42pm UTC](https://discourse.shapr3d.com/t/solids-from-patterns-and-parametric-changes/41282/3 "2026-07-22T13:42:00Z")

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I’m going to be somewhat cryptic, because this is related to this weeks challenge.

I personally don’t consider that extrusion warning an issue, because if you go back to from 3 to 5 extrusions, they will be executed again no problem, same as the initial state.

This is my personal take on this. Mods, feel free to delete if you think this might be misleading or over the line.

I’m generally not too bothered with warnings in the history. If i was to share my designs I might clean them up when I’m done modeling. For myself? Eh..

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**Author:** ![bidek](https://avatars.discourse-cdn.com/v4/letter/b/e5b9ba/32.png) [@bidek](https://discourse.shapr3d.com/u/bidek)\
**Post date:** [July 22, 2026, 7:23pm UTC](https://discourse.shapr3d.com/t/solids-from-patterns-and-parametric-changes/41282/4 "2026-07-22T19:23:23Z")

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You are currently patterning the sketch.  
Try modeling one cylinder first, then apply the pattern to the body instead of the sketch.

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**Author:** ![DrKronos](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/drkronos/32/36064_2.png) [@DrKronos](https://discourse.shapr3d.com/u/DrKronos)\
**Post date:** [July 22, 2026, 8:03pm UTC](https://discourse.shapr3d.com/t/solids-from-patterns-and-parametric-changes/41282/5 "2026-07-22T20:03:42Z")

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Not allowed for the weekly challenge. 😉