# Bug when rotating involute gear face on 3D gear

**URL:** <https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991>\
**Category:** Modeling Questions\
**Created:** [February 7, 2023, 4:56am UTC](https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991 "2023-02-07T04:56:27Z")\
**Posts on this page:** 11\
**Page:** 1

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**Author:** ![mwetzko](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/mwetzko/32/18991_2.png) [@mwetzko](https://discourse.shapr3d.com/u/mwetzko)\
**Post date:** [February 7, 2023, 4:56am UTC](https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991/1 "2023-02-07T04:56:27Z")

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If you extrude a gear plane imported from \*.dxf, and try to (twist)rotate it, it snaps back into original position with an error: “Edge transformation failed.”

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**Author:** ![NathanD](https://avatars.discourse-cdn.com/v4/letter/n/dec6dc/32.png) [@NathanD](https://discourse.shapr3d.com/u/NathanD)\
**Post date:** [February 7, 2023, 5:42am UTC](https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991/2 "2023-02-07T05:42:03Z")

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Are you trying to twist one face and make the gear almost helical, or simply rotate the body’s position?

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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:** [February 7, 2023, 6:24am UTC](https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991/3 "2023-02-07T06:24:05Z")

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Here is a gear face rotated. I imported the STEP file from McMaster-Carr.

[https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/1/7/17f30da1a49f8683886e3701a7a5958300dbd9bc.mov](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/1/7/17f30da1a49f8683886e3701a7a5958300dbd9bc.mov)

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**Author:** ![mwetzko](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/mwetzko/32/18991_2.png) [@mwetzko](https://discourse.shapr3d.com/u/mwetzko)\
**Post date:** [February 7, 2023, 3:13pm UTC](https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991/4 "2023-02-07T15:13:29Z")

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@NathanD, Exactly like @TigerMike is doing, but does not work for me. I have one DXF, where it can only be twisted 5°, and another, where you can twist it 7°, 8°, 9°, 11°, 12°, 13°,14° but not 10° or 15° or 20° or higher than 20°. The app freezes trying to calculate and bugs out as described.

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**Author:** ![Laci\_K](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/laci_k/32/8196_2.png) [@Laci\_K](https://discourse.shapr3d.com/u/Laci_K)\
**Post date:** [February 7, 2023, 3:58pm UTC](https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991/5 "2023-02-07T15:58:54Z")

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It can depend on the dxf. If it has a ton of control points, it creates a lot of surfaces once extruded, if edges of these surfaces overlap / intersect eachother, the body won’t be valid.

Can you upload the .dxf file for us to check? If it’s confidential, you can open a support ticket at [https://support.shapr3d.com/hc/en-us/requests/new](https://support.shapr3d.com/hc/en-us/requests/new)

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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:** [February 7, 2023, 4:42pm UTC](https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991/6 "2023-02-07T16:42:44Z")

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The gear at the bottom is what I used to do the rotate. Projecting the surface on a new plane and extruding a new gear produces your problem. My newly extruded gear cannot be rotated. Note the projected sketch with many many segments which is the problem.

[https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/d/5/d517de78cd66eb8b57b78a132fef73f499857ea3.mov](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/d/5/d517de78cd66eb8b57b78a132fef73f499857ea3.mov)

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**Author:** ![mwetzko](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/mwetzko/32/18991_2.png) [@mwetzko](https://discourse.shapr3d.com/u/mwetzko)\
**Post date:** [February 7, 2023, 5:03pm UTC](https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991/7 "2023-02-07T17:03:55Z")

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New users cannot upload files. Sorry!

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**Author:** ![mwetzko](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/mwetzko/32/18991_2.png) [@mwetzko](https://discourse.shapr3d.com/u/mwetzko)\
**Post date:** [February 7, 2023, 5:04pm UTC](https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991/8 "2023-02-07T17:04:00Z")

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I assume, @TigerMike 's teeth are made of arc lines instead of connected dots, which my files have. So somehow the amount of dots forming a tooth seems to be too much for the 3D calculation. On the other hand, why some angles work, others dont? Odd…

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**Author:** ![KPeter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/kpeter/32/7644_2.png) [@KPeter](https://discourse.shapr3d.com/u/KPeter)\
**Post date:** [February 8, 2023, 3:13pm UTC](https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991/9 "2023-02-08T15:13:48Z")

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Hi @mwetzko, thanks for submitting the model to our support!

Can you please share a few details about the sketch of the gear? It is made of a lot of spline segments, which during the extrusion create the same amount of small faces along the profile. When you rotate the top face, these small faces around it can intersect and cover each other which could end up in an open polysurface instead of a closed solid body and Shapr3D does not allow the transformation to be finished.

The gear @TigerMike imported is a much cleaner model, it has a significantly smaller amount of faces along the teeth, I guess the input was also a simpler set of curves.

_ps.: you should be able to upload files from now_

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**Author:** ![mwetzko](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/mwetzko/32/18991_2.png) [@mwetzko](https://discourse.shapr3d.com/u/mwetzko)\
**Post date:** [February 8, 2023, 6:24pm UTC](https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991/10 "2023-02-08T18:24:04Z")

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Yes, the original taken from [3D Gear Generator | STL file for 3D Printing Gears – Evolvent Design](https://evolventdesign.com/pages/gear-stl-generator) has a lot of spline segments. I replaced the teeth with an arc drawing and rotates now without issues. Unfortunately this costs extra time to fix. But still wondering that some angles work, others dont.

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<div class="post-metadata">

**Author:** ![KPeter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/kpeter/32/7644_2.png) [@KPeter](https://discourse.shapr3d.com/u/KPeter)\
**Post date:** [February 8, 2023, 6:58pm UTC](https://discourse.shapr3d.com/t/bug-when-rotating-involute-gear-face-on-3d-gear/23991/11 "2023-02-08T18:58:02Z")

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It can happen that overlap occurs between the transformed neighboring faces, but just in certain positions, for example. The overlap then results in a zero thickness issue which makes the transformation fail.

The actual problem depends on many things but happens quite rarely if the input sketch is clean. This is a regular issue with online converters and generators, by the way, the output is way over defined compared to what the given shape would require.