# Making trimmed surfaces "non-trimmed"

**URL:** <https://discourse.mcneel.com/t/making-trimmed-surfaces-non-trimmed/33639>\
**Category:** Rhino for Windows\
**Created:** [June 20, 2016, 8:33pm UTC](https://discourse.mcneel.com/t/making-trimmed-surfaces-non-trimmed/33639 "2016-06-20T20:33:49Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![RIL](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/ril/32/768639_2.png) [@RIL](https://discourse.mcneel.com/u/RIL)\
**Post date:** [June 20, 2016, 8:33pm UTC](https://discourse.mcneel.com/t/making-trimmed-surfaces-non-trimmed/33639/1 "2016-06-20T20:33:49Z")

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Hi all,  
I’m having problems with MatchSurface on trimmed surfaces (the trimmed surface-edges can’t be selected for matching). However, my workflow forced me to trim the surfaces, but due to the curvature complexity, bending and twisting, I have to match the surfaces again.

**Q** : But, since the trimmed surface edges (no longer) can’t be selected the question follows: **Is it possible to keep the trimmed surface shape, but somehow make the surface appear as “not-trimmed”?** That is, how can I get rid of the underlaying original surface and only keep the new (trimmed) contour as an “original” surface, which then can be used in the MatchSurface command?

// Rolf

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**Author:** ![pascal](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/pascal/32/479395_2.png) [@pascal](https://discourse.mcneel.com/u/pascal)\
**Post date:** [June 20, 2016, 8:44pm UTC](https://discourse.mcneel.com/t/making-trimmed-surfaces-non-trimmed/33639/2 "2016-06-20T20:44:12Z")

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Hi Rolf - Unttrim or UntrimBorder will help - it will restore the underlying surface. It may be that the underlying edge is too far from the trimmed edge you care about to be useful - in that case using ShrinkTrimmedSrf before untrimming may, in some cases, help enough.

-Pascal

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<div class="post-metadata">

**Author:** ![RIL](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/ril/32/768639_2.png) [@RIL](https://discourse.mcneel.com/u/RIL)\
**Post date:** [June 20, 2016, 10:21pm UTC](https://discourse.mcneel.com/t/making-trimmed-surfaces-non-trimmed/33639/3 "2016-06-20T22:21:04Z")

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Yes, [quote=“pascal, post:2, topic:33639”]using ShrinkTrimmedSrf( **ToEdge** ) before untrimming[/quote] does what I want.

I had already tried “ShrinkTrimmedSrf **ToEdge** ”, but didn’t try _Untrim_ on top of that.

Many thanks. Now it seems I can actually fix cussed surfaces…

// Rolf