# Lofting extrusion around curve

**URL:** <https://discourse.shapr3d.com/t/lofting-extrusion-around-curve/37043>\
**Category:** Modeling Questions\
**Created:** [March 15, 2025, 6:49pm UTC](https://discourse.shapr3d.com/t/lofting-extrusion-around-curve/37043 "2025-03-15T18:49:23Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![alexM](https://avatars.discourse-cdn.com/v4/letter/a/3da27b/32.png) [@alexM](https://discourse.shapr3d.com/u/alexM)\
**Post date:** [March 15, 2025, 6:49pm UTC](https://discourse.shapr3d.com/t/lofting-extrusion-around-curve/37043/1 "2025-03-15T18:49:23Z")

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I am having trouble using the Loft tool to transition around a curved line from a sketch to another sketch. Getting the error: Operation Failed because the resulting body wouldn’t be valid. I don’t get any error if I omit the Guide Curve, however this is not the result I want. I want the part to follow the curve. The sketches are on different planes if that makes any difference. Any idea what I am doing wrong here?

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/1/5/15b469174bd6a30d5fe65a33b9228e4338d8c9d5.jpeg)

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/2/2/22bc96580db3b0bb08483375dee978e9cf082e96.jpeg)

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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:** [March 15, 2025, 8:03pm UTC](https://discourse.shapr3d.com/t/lofting-extrusion-around-curve/37043/3 "2025-03-15T20:03:18Z")

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The guide line should start at the first cros-section, and must be finished at the last.

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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, 2025, 8:04pm UTC](https://discourse.shapr3d.com/t/lofting-extrusion-around-curve/37043/4 "2025-03-15T20:04:59Z")

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**Loft** would be a little difficult as you would need to add guide lines.  
I think **Sweep** is the way to go.

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<div class="post-metadata">

**Author:** ![alexM](https://avatars.discourse-cdn.com/v4/letter/a/3da27b/32.png) [@alexM](https://discourse.shapr3d.com/u/alexM)\
**Post date:** [March 15, 2025, 8:11pm UTC](https://discourse.shapr3d.com/t/lofting-extrusion-around-curve/37043/5 "2025-03-15T20:11:45Z")

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I was trying to transition from a larger cross section to a smaller one using Loft. I think the Sweep tool keeps the starting and ending size exactly the same?

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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:** [March 15, 2025, 8:28pm UTC](https://discourse.shapr3d.com/t/lofting-extrusion-around-curve/37043/6 "2025-03-15T20:28:52Z")

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You will need more guideline to make it work.

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/0/c/0c939154a8b7eec8330658db6595a292b74155a5.jpeg)

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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:** [March 15, 2025, 8:40pm UTC](https://discourse.shapr3d.com/t/lofting-extrusion-around-curve/37043/7 "2025-03-15T20:40:19Z")

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You’re right about **Sweep**. I couldn’t tell by your initial pic that both sketches were different.  
As mentioned, you’ll need a few guidelines in order to use **Loft** effectively. FWIW, here’s another way to go assuming only the height changes at one end.