# 3D guide curves

**URL:** <https://discourse.shapr3d.com/t/3d-guide-curves/16472>\
**Category:** Modeling Questions\
**Created:** [December 22, 2021, 9:51am UTC](https://discourse.shapr3d.com/t/3d-guide-curves/16472 "2021-12-22T09:51:44Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![Renato](https://avatars.discourse-cdn.com/v4/letter/r/858c86/32.png) [@Renato](https://discourse.shapr3d.com/u/Renato)\
**Post date:** [December 22, 2021, 9:51am UTC](https://discourse.shapr3d.com/t/3d-guide-curves/16472/1 "2021-12-22T09:51:44Z")

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Hi everyone,

I am new to Shapr3D and I was trying to design this glider fuselage but I couldn’t find a way to add this 3D guide curve (Red in the image below). The problem is I only have 3 frames and using other CAD softwares I would design 3 frames + 4 guide curves (Top, bottom, right side and letft side) and loft. But the right side and left side is a 3D curve as you can see in the picture below. Do you have an idea about how can I do this ?

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/e/e6c660454bb1a2f885938fad56eb72b56b3cd447.jpeg)

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**Author:** ![Renato](https://avatars.discourse-cdn.com/v4/letter/r/858c86/32.png) [@Renato](https://discourse.shapr3d.com/u/Renato)\
**Post date:** [December 22, 2021, 9:57am UTC](https://discourse.shapr3d.com/t/3d-guide-curves/16472/2 "2021-12-22T09:57:11Z")

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Using solids I could manage to get this edge (the same shape of the 3D guide curve), but I can’t use it with the loft operation ☹ … Any trick to overcome this issue?

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/8/8185502ce924cedd47dce21fae920a48e10e0652.jpeg)

Many many thanks in advance  
Renato

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**Author:** ![Istvan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/istvan/32/23668_2.png) [@Istvan](https://discourse.shapr3d.com/u/Istvan)\
**Post date:** [December 22, 2021, 10:01am UTC](https://discourse.shapr3d.com/t/3d-guide-curves/16472/3 "2021-12-22T10:01:23Z")

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I’m not 100% sure if this would work, but I’d try to create a flat guide curve from the top view, and then project it to a curved face that would follow the profile.

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**Author:** ![Renato](https://avatars.discourse-cdn.com/v4/letter/r/858c86/32.png) [@Renato](https://discourse.shapr3d.com/u/Renato)\
**Post date:** [December 22, 2021, 10:07am UTC](https://discourse.shapr3d.com/t/3d-guide-curves/16472/4 "2021-12-22T10:07:46Z")

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![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/2/293e443eb4e6ef899b983e5c2675359417ddf45d.jpeg)

Like this?

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**Author:** ![Renato](https://avatars.discourse-cdn.com/v4/letter/r/858c86/32.png) [@Renato](https://discourse.shapr3d.com/u/Renato)\
**Post date:** [December 22, 2021, 10:08am UTC](https://discourse.shapr3d.com/t/3d-guide-curves/16472/5 "2021-12-22T10:08:21Z")

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The problem is that when I try to select the projected line, it can only select parts of it, it seems that it can’t be used as a curve.

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/3/3012cc84e5486f3f29139f80dbc44a03319bde1f.jpeg)

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<div class="post-metadata">

**Author:** ![Renato](https://avatars.discourse-cdn.com/v4/letter/r/858c86/32.png) [@Renato](https://discourse.shapr3d.com/u/Renato)\
**Post date:** [December 22, 2021, 10:32am UTC](https://discourse.shapr3d.com/t/3d-guide-curves/16472/6 "2021-12-22T10:32:26Z")

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It did work!!

When doing the loft operation we have to select **all the parts** of the projected curve first, then the other guide curves and finally the frames it works 😉 Brilliant!!!

Many many thanks!!  
Cheers  
Renato

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/1/1c6db3344d4566c7a23ce2d596fac2bb408cb481.png)

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**Author:** ![JST](https://avatars.discourse-cdn.com/v4/letter/j/edb3f5/32.png) [@JST](https://discourse.shapr3d.com/u/JST)\
**Post date:** [December 22, 2021, 12:21pm UTC](https://discourse.shapr3d.com/t/3d-guide-curves/16472/7 "2021-12-22T12:21:08Z")

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And finally you should make many sections for the rounded nose 🕶

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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:** [December 22, 2021, 12:51pm UTC](https://discourse.shapr3d.com/t/3d-guide-curves/16472/8 "2021-12-22T12:51:04Z")

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Hi @Renato, that seems to be a nice project!  
If you are drawing just half of the fuselage, please make sure that the splines that define the cross-section are starting perpendicular to the mirror plane. To achieve that, please place the first and the second (and the last and the one before the last) control point on an imaginary line that is perpendicular to the plane you will mirror around. This way the mirrored body will be smooth along the mirror plane.

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**Author:** ![Renato](https://avatars.discourse-cdn.com/v4/letter/r/858c86/32.png) [@Renato](https://discourse.shapr3d.com/u/Renato)\
**Post date:** [December 22, 2021, 2:56pm UTC](https://discourse.shapr3d.com/t/3d-guide-curves/16472/9 "2021-12-22T14:56:49Z")

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Many thanks for the tips guys 🙂

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/a/ab8a28ad9d24da0d4db5b1b3372ee1168d63c98f.jpeg)

Cheers  
Renato