# Accurate method to wrap a sketch to a cylinder

**URL:** <https://discourse.shapr3d.com/t/accurate-method-to-wrap-a-sketch-to-a-cylinder/18024>\
**Category:** Share your creations\
**Created:** [March 15, 2022, 1:08am UTC](https://discourse.shapr3d.com/t/accurate-method-to-wrap-a-sketch-to-a-cylinder/18024 "2022-03-15T01:08:29Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![PEC](https://avatars.discourse-cdn.com/v4/letter/p/67e7ee/32.png) [@PEC](https://discourse.shapr3d.com/u/PEC)\
**Post date:** [March 15, 2022, 1:08am UTC](https://discourse.shapr3d.com/t/accurate-method-to-wrap-a-sketch-to-a-cylinder/18024/1 "2022-03-15T01:08:29Z")

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Hi,  
I think this has not been posted before, here is an accurate method to wrap a sketch onto a cylinder.  
 ![CleanShot 2022-03-22 at 00.35.36](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/f/f6b52277cf3a42b284037d7c4b2a92d13db8e313.gif)

Orthogonal projection of a plane onto a cylinder creates distorsion. One solution is obviously to slice the cylinder to reduce error. The following table gives an estimation of the maximum error of the projection for a given number of slices.

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/a/a2daea0106f7aa194ff874094ac846afdf61c5d6.png)  
2 slices means projection of a plane on half the cylinder, which leads to infinite distorsion at the limit of the projection.  
With 16 slices, worse case error is less than 2%, which is not noticeable.  
With 64 slices, worse case error is about 0.1%.

The idea is to create a flatten version of the cylinder, project the sketch on the flatten version, extrude it if needed, and then wrap the cylinder to create the final shape in a systematic way, using mirror and align tools.  
It’s a five minutes process for 16 slices, as in the video, but it just requires 1 additional minute to go to 32 slices 😀 and do not require any computation at all.

_There is only one limitation: ensure there are no spline control point too close (less than 0.01mm) to any slice’s edge or extrude may fail._

This method can be extended to project a sketch onto a cone 🙂  
[Accurate method to wrap a sketch around a cone](https://discourse.shapr3d.com/t/accurate-method-to-wrap-a-sketch-around-a-cone/18234)

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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:** [March 15, 2022, 2:19am UTC](https://discourse.shapr3d.com/t/accurate-method-to-wrap-a-sketch-to-a-cylinder/18024/2 "2022-03-15T02:19:18Z")

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Excellent demonstration. Bravo!

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**Author:** ![Hammerhand](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/hammerhand/32/13455_2.png) [@Hammerhand](https://discourse.shapr3d.com/u/Hammerhand)\
**Post date:** [March 15, 2022, 6:08am UTC](https://discourse.shapr3d.com/t/accurate-method-to-wrap-a-sketch-to-a-cylinder/18024/3 "2022-03-15T06:08:37Z")

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Super helpful right now. Thank you.

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**Author:** ![welshsteve](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/welshsteve/32/16111_2.png) [@welshsteve](https://discourse.shapr3d.com/u/welshsteve)\
**Post date:** [March 16, 2022, 1:40pm UTC](https://discourse.shapr3d.com/t/accurate-method-to-wrap-a-sketch-to-a-cylinder/18024/5 "2022-03-16T13:40:23Z")

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Great work ‘around’ (pun intended) and exactly the way that I’ve been doing it both here in Shapr3d and in SketchUp.

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**Author:** ![PEC](https://avatars.discourse-cdn.com/v4/letter/p/67e7ee/32.png) [@PEC](https://discourse.shapr3d.com/u/PEC)\
**Post date:** [March 20, 2022, 5:21pm UTC](https://discourse.shapr3d.com/t/accurate-method-to-wrap-a-sketch-to-a-cylinder/18024/7 "2022-03-20T17:21:28Z")

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Hi Macher, welcome to this forum.

> [@Macher](#):
>
> My boss would now say:  
> A typical example of how to replace a standard CAD function with as much effort as possible.

I think your boss should not say that as he would be mixing to separate topics.

If the question is “do we miss a wrapping or emboss function”, the answer is _yes_, no debate on that. The minute it will be available, we will all use it.

But at present, we don’t have wrap or emboss tool, leaving only two things we can do:

- ask for it : it has been requested several time so I’m 100% sure the Shapr3D’s team is aware of this;
- find the best solution to replace this CAD function with **as little** effort as possible for those who don’t have access to Solidworks, Fusion360, Inventor, Rhino, etc on their tablets, which was my two cents’ contribution.

So now I’m afraid that you put your boss intro troubles 😉 as he will have to prove he is the boss 😇  
Can he beat 1 minute with no visible distorsion, using only Shapr3D and a better method? Lets call it the _One minute challenge_ ! 🥇  
 ![CleanShot 2022-03-20 at 17.44.40](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/d/d7f4f28b81d8af48792b0dc350de802b08199c50.gif)

- The first step of the method, you have to do it only once in a lifetime, as you can save the flatten shape and scale it to the desired diameter when you re-use it, as in the video;
- The second step = the sketch, you have do do it anyhow, so it is not taken into account for the time.