# Confused about sweep

**URL:** <https://discourse.shapr3d.com/t/confused-about-sweep/7065>\
**Category:** Modeling Questions\
**Created:** [April 2, 2020, 3:36pm UTC](https://discourse.shapr3d.com/t/confused-about-sweep/7065 "2020-04-02T15:36:58Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![RonJeffries](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/ronjeffries/32/5708_2.png) [@RonJeffries](https://discourse.shapr3d.com/u/RonJeffries)\
**Post date:** [April 2, 2020, 3:36pm UTC](https://discourse.shapr3d.com/t/confused-about-sweep/7065/1 "2020-04-02T15:36:58Z")

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what seems to work: draw a spline to follow; draw a closed profile; position the profile near one end of the spline; rotate the profile to be approximately face-normal to the spline i.e. face normal aligned with tangent at near end; sweep. .

if the profile is not near the spline it seems to swerve oddly and the resulting tube isn’t shaped like the spline, especially at the beginning. if the profile isn’t close to face normal, i often get a message about intersecting geometry.

is this expected? what are the rules?

thanks!

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**Author:** ![Gelphyn](https://avatars.discourse-cdn.com/v4/letter/g/db5fbb/32.png) [@Gelphyn](https://discourse.shapr3d.com/u/Gelphyn)\
**Post date:** [April 2, 2020, 3:53pm UTC](https://discourse.shapr3d.com/t/confused-about-sweep/7065/2 "2020-04-02T15:53:58Z")

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@RonJeffries  
Sketch any single Line or Curve.  
Use **Add \> Construction pane** \> choose the type **Perpendicular to a Point**  
Move the Point, if necessary, to the appropriate position on the chosen Line or Curve  
Sketch the Profile, to be Swep,t on the New Plane, this can be centred On or Near the Line or Curve End  
Alternatively experiment at will with any position on the Plane.

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**Author:** ![RonJeffries](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/ronjeffries/32/5708_2.png) [@RonJeffries](https://discourse.shapr3d.com/u/RonJeffries)\
**Post date:** [April 2, 2020, 5:06pm UTC](https://discourse.shapr3d.com/t/confused-about-sweep/7065/3 "2020-04-02T17:06:12Z")

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So … I interpret this to be saying that we pretty much need the swept figure to be perpendicular to the curve? So far my experiments lead to errors a lot. I’ll keep trying …

Thanks …

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**Author:** ![Gelphyn](https://avatars.discourse-cdn.com/v4/letter/g/db5fbb/32.png) [@Gelphyn](https://discourse.shapr3d.com/u/Gelphyn)\
**Post date:** [April 2, 2020, 5:37pm UTC](https://discourse.shapr3d.com/t/confused-about-sweep/7065/4 "2020-04-02T17:37:51Z")

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Exactly, otherwise it will wander off course.