# How does auto orient work in PreForm?

**URL:** <https://forum.formlabs.com/t/how-does-auto-orient-work-in-preform/45372>\
**Category:** General Discussion\
**Created:** [September 7, 2025, 6:27pm UTC](https://forum.formlabs.com/t/how-does-auto-orient-work-in-preform/45372 "2025-09-07T18:27:33Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![strojano](https://avatars.discourse-cdn.com/v4/letter/s/6f9a4e/32.png) [@strojano](https://forum.formlabs.com/u/strojano)\
**Post date:** [September 7, 2025, 6:27pm UTC](https://forum.formlabs.com/t/how-does-auto-orient-work-in-preform/45372/1 "2025-09-07T18:27:33Z")

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My question is: how does auto orient work in PreForm?  
What is taken into consideration when calculating the object’s angle?  
Sometimes I use this function, and the results are not always consistent. As shown in the picture, a slightly larger object has a much higher angle than a smaller one.

All objects on this screen were oriented using auto-orient:

 ![image](https://us1.discourse-cdn.com/flex025/uploads/formlabs/original/3X/c/d/cdd6766030885a6c2bd98ebbc6286105117e8c4b.jpeg)

My usual workflow for resin 3D prints (on Formlabs and Anycubic printers): I take the pixel size (in the case of Form 3, the laser spot size) and calculate the tangent of layer thickness divided by laser spot size. For the Form 3 by layer thickness:

- **0.1mm = 49.6355°**

- **0.05mm = 30.4655°**

- **0.025mm = 16.3895°**

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**Author:** ![Kemolagger](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.formlabs.com/kemolagger/32/22003_2.png) [@Kemolagger](https://forum.formlabs.com/u/Kemolagger)\
**Post date:** [September 8, 2025, 2:15am UTC](https://forum.formlabs.com/t/how-does-auto-orient-work-in-preform/45372/2 "2025-09-08T02:15:54Z")

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Ah yes, good ole arctan angles. I’m not sure how auto orient figures it out, and only when I do auto orient will it sometimes change a little. When I use the 1-click feature, models always orient in the same way, no matter if I delete the file and reopen it - it’s been consistent. I get better results with my prints using the 1 click than if I were to orient and edit support points myself. I know that not everyone has that experience, but for the most part it’s been solid

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**Author:** ![JoaoMarcos](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.formlabs.com/joaomarcos/32/22245_2.png) [@JoaoMarcos](https://forum.formlabs.com/u/JoaoMarcos)\
**Post date:** [September 10, 2025, 6:44pm UTC](https://forum.formlabs.com/t/how-does-auto-orient-work-in-preform/45372/3 "2025-09-10T18:44:05Z")

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I feel that some of the variables to the auto-orientation are:

- Reduce the area of the printing layer (mainly the first ones) to minimize the peeling force. So the the angle of the part will be a consequence, not taken really in count for the software;
- Try to avoid cups;
- Optmize supports spending less material;

But as you just realized, it is not a consistent method, if you take the same part and auto-orient it, the software will not always orient it in the same way.

My tip is not to use this tool hahaha orienting parts is a subjective skill that is easy to learn, and there is not always a “best” way to do it, sometimes is just your feeling. In my case I prioritize the accuracy and geometric characteristics.

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**Author:** ![davidbirkas](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.formlabs.com/davidbirkas/32/21104_2.png) [@davidbirkas](https://forum.formlabs.com/u/davidbirkas)\
**Post date:** [September 10, 2025, 9:01pm UTC](https://forum.formlabs.com/t/how-does-auto-orient-work-in-preform/45372/4 "2025-09-10T21:01:06Z")

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Hi @strojano,

The auto-orient algorithm can converge on different local minima and uses [random optimization](https://en.wikipedia.org/wiki/Random_optimization#:~:text=Random%20optimization%20(RO)%20is%20a,%2C%20or%20black%2Dbox%20methods.). This is why running auto-orient multiple times may yield different results. The algorithm itself is trying to:

- Make sure the result fits into the given build volume

- Minimize the number of minima vertices

- Avoid small angles with build platform

- Minimize build platform parallel surfaces

- etc…

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**Author:** ![strojano](https://avatars.discourse-cdn.com/v4/letter/s/6f9a4e/32.png) [@strojano](https://forum.formlabs.com/u/strojano)\
**Post date:** [September 11, 2025, 10:48am UTC](https://forum.formlabs.com/t/how-does-auto-orient-work-in-preform/45372/5 "2025-09-11T10:48:50Z")

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Thank you. This is exactly what I want to know.

BR,  
Sebastian

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**Author:** ![system](https://us1.discourse-cdn.com/flex025/uploads/formlabs/original/3X/5/b/5bc2bdf993ff27c2e0eecab5010b25626fbb327a.png) [@system](https://forum.formlabs.com/u/system)\
**Post date:** [March 12, 2026, 10:48pm UTC](https://forum.formlabs.com/t/how-does-auto-orient-work-in-preform/45372/6 "2026-03-12T22:48:54Z")

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Closed on March 12, 2026, 10:48pm UTC

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