# Drawing/sketching spline between planes (flexible tubing)

**URL:** <https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537>\
**Category:** Modeling Questions\
**Created:** [December 11, 2024, 1:28am UTC](https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537 "2024-12-11T01:28:24Z")\
**Posts on this page:** 11\
**Page:** 1

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**Author:** ![NitroSpeed15](https://avatars.discourse-cdn.com/v4/letter/n/b3f665/32.png) [@NitroSpeed15](https://discourse.shapr3d.com/u/NitroSpeed15)\
**Post date:** [December 11, 2024, 1:28am UTC](https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537/1 "2024-12-11T01:28:24Z")

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Good evening, as my title implies, I’m trying to create a realistic model of an existing fuel line (for the purposes of running CFD simulations). I have tried lofting and sweeping.

I’ve seen videos where a spline is drawn, then swept from a face, but I believe that was done in the same plane. My planes aren’t parallel or perpendicular. I’m attaching a SS of my last attempt, where I tried to copy/move a pile of circles and loft/sweep between them. I’ve fought this until I’m crosseyed; feel like I’m overlooking a simple trick!!!

I’ve probably spent 100 hours on the rest of this model (isolated right now), and have been able to figure things out…but _this one_ is whipping me!!!

 ![Screenshot 2024-12-10 at 8.23.47 PM](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/2/6/26f4d8c66a16c88afa886cbacb492556f9696ee8.jpeg)

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**Author:** ![SCALEMODEL](https://avatars.discourse-cdn.com/v4/letter/s/77aa72/32.png) [@SCALEMODEL](https://discourse.shapr3d.com/u/SCALEMODEL)\
**Post date:** [December 11, 2024, 2:37am UTC](https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537/2 "2024-12-11T02:37:21Z")

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What you did looks right for Loft tool. When you loft from one circle to next what happens?

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**Author:** ![NitroSpeed15](https://avatars.discourse-cdn.com/v4/letter/n/b3f665/32.png) [@NitroSpeed15](https://discourse.shapr3d.com/u/NitroSpeed15)\
**Post date:** [December 11, 2024, 3:16am UTC](https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537/3 "2024-12-11T03:16:15Z")

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It does this (attached image). It doesn’t show an error message. I’m really confused about selecting faces vs “sketches,” and may be doing this wrong. I did get it to loft, once, but only connected most of the sections (it left a gap between the tank and pipe; the tank is on the right side of the image).

 ![Screenshot 2024-12-10 at 10.10.38 PM](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/2/f/2ff94a34c13a0131288529b76a043373c1d53764.jpeg)

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**Author:** ![NitroSpeed15](https://avatars.discourse-cdn.com/v4/letter/n/b3f665/32.png) [@NitroSpeed15](https://discourse.shapr3d.com/u/NitroSpeed15)\
**Post date:** [December 11, 2024, 3:27am UTC](https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537/4 "2024-12-11T03:27:32Z")

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Actually, I have to select a face **and** circle for the loft tool to appear. If I only select circles it stays hidden. Even so, it will often appear, and I will get the result in the last image…which is nothing. I know it’s something I’m doing wrong, just not sure what.

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**Author:** ![SCALEMODEL](https://avatars.discourse-cdn.com/v4/letter/s/77aa72/32.png) [@SCALEMODEL](https://discourse.shapr3d.com/u/SCALEMODEL)\
**Post date:** [December 11, 2024, 3:42am UTC](https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537/5 "2024-12-11T03:42:08Z")

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Ok you’re trying to loft from a tube to the circle. Loft tool doesn’t know how to transform from a tube to circle. So I would make end of your tube a solid cylinder, now all the circles should loft.

After your loft is complete shell it so that it turns from solid to a tube. And after you shell one the other side is blocked so add the face of the other side to make it open tube.

 ![Screenshot 2024-12-10 at 7.40.05 PM](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/c/7/c706949d6ce8ebd6d71178aadd2923aab159704f.jpeg)

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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:** [December 11, 2024, 4:32am UTC](https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537/6 "2024-12-11T04:32:29Z")

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I used Sweep.

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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:** [December 11, 2024, 5:21am UTC](https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537/7 "2024-12-11T05:21:43Z")

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And here’s a slight variation.

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**Author:** ![NitroSpeed15](https://avatars.discourse-cdn.com/v4/letter/n/b3f665/32.png) [@NitroSpeed15](https://discourse.shapr3d.com/u/NitroSpeed15)\
**Post date:** [December 11, 2024, 12:05pm UTC](https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537/8 "2024-12-11T12:05:03Z")

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Thank You!!! I added a construction plane .010 off the face of the tank inlet, and sketched a solid circle, but it still didn’t work. Then I remembered reading that somewhere that “order of operations” matters, so I selected the loft tool, THEN the series of solid circles, and it worked! It’s not a 100% perfect silicone tube, but it’s very very close. Thanks again for the help!

 ![fuel-line](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/d/5/d51de24db6855c4dbc266cd1b911c2db151152ec.jpeg)

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<div class="post-metadata">

**Author:** ![NitroSpeed15](https://avatars.discourse-cdn.com/v4/letter/n/b3f665/32.png) [@NitroSpeed15](https://discourse.shapr3d.com/u/NitroSpeed15)\
**Post date:** [December 11, 2024, 12:12pm UTC](https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537/9 "2024-12-11T12:12:15Z")

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I obviously have a lot to learn. That was very enlightening. I am going to practice that approach. This may be a very elementary question, but how could you measure the geometry between the 2 points, then use your sweep approach? Your swept tube is a lot higher quality than the one I lofted.

I have struggled quite a bit measuring between things in Shapr. I know it’s because of the way I’m setting up construction geometry, just don’t have a feel for it yet.

Thanks for the advice and demo!

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<div class="post-metadata">

**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:** [December 11, 2024, 6:05pm UTC](https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537/10 "2024-12-11T18:05:31Z")

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Here’s an example. I selected both beginning and ending circle edges. Note at the bottom lower right of the screen there are measurements- deltaX, Y, and Z (shown just before the transition). It gets a little more complicated when the two pipes are at different angles to each other but still doable.

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**Author:** ![KEKE63](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/keke63/32/34162_2.png) [@KEKE63](https://discourse.shapr3d.com/u/KEKE63)\
**Post date:** [January 24, 2025, 2:59pm UTC](https://discourse.shapr3d.com/t/drawing-sketching-spline-between-planes-flexible-tubing/35537/11 "2025-01-24T14:59:31Z")

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Thank you very much.  
I added picture, for a better understanding.