# Intersection?

**URL:** <https://discourse.mcneel.com/t/intersection/81073>\
**Category:** Rhino for Windows\
**Created:** [March 29, 2019, 4:22pm UTC](https://discourse.mcneel.com/t/intersection/81073 "2019-03-29T16:22:50Z")\
**Posts on this page:** 11\
**Page:** 1

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**Author:** ![Robb](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/robb/32/474290_2.png) [@Robb](https://discourse.mcneel.com/u/Robb)\
**Post date:** [March 29, 2019, 4:22pm UTC](https://discourse.mcneel.com/t/intersection/81073/1 "2019-03-29T16:22:50Z")

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I have two identical surfaces opposing and intersecting each other at 90 degrees. They obviously are in the same plane and obviously appear to intersect yet using the trim or intersect command these are not recognized as intersecting. There exists a work around or two and I’ve had success with those but it still doesn’t address the fundamental problem. I am likely missing something but still need some advice out there.

 ![intersection%20failure](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/f/5/f504845f80b4f6e01b15e3b29a137668d10f11c2.jpeg)[intersection failure.3dm](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/8/2/82f5b20b8c94ad007d310afab9b3e76902955de2.3dm) (4.5 MB)

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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:** [March 29, 2019, 4:34pm UTC](https://discourse.mcneel.com/t/intersection/81073/2 "2019-03-29T16:34:25Z")

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Hello - I see there’s a problem here - I’m poking at it… thanks for the example.  
[https://mcneel.myjetbrains.com/youtrack/issue/RH-51701](https://mcneel.myjetbrains.com/youtrack/issue/RH-51701)  
-Pascal

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**Author:** ![encephalon](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/encephalon/32/611970_2.png) [@encephalon](https://discourse.mcneel.com/u/encephalon)\
**Post date:** [March 29, 2019, 6:26pm UTC](https://discourse.mcneel.com/t/intersection/81073/3 "2019-03-29T18:26:49Z")

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use DivideAlongCreases check all and voila it splits and trims and all you need. did you by any chance merge the fillets without option smooth? or how did you create the profile, can you post the input curve?

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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:** [March 29, 2019, 6:27pm UTC](https://discourse.mcneel.com/t/intersection/81073/4 "2019-03-29T18:27:45Z")

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I still got a funky intersection after dividing along creases here, so I left it as is for the bug report.

-Pascal

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**Author:** ![encephalon](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/encephalon/32/611970_2.png) [@encephalon](https://discourse.mcneel.com/u/encephalon)\
**Post date:** [March 29, 2019, 6:34pm UTC](https://discourse.mcneel.com/t/intersection/81073/5 "2019-03-29T18:34:04Z")

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> [@pascal](#):
>
> funky intersection

i get square dance intersections

 ![funky%20squaredance](https://global.discourse-cdn.com/mcneel/original/3X/a/b/ab5d8677d145898a752a237bbf7d24478aaa4aeb.png)

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<div class="post-metadata">

**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:** [March 29, 2019, 6:36pm UTC](https://discourse.mcneel.com/t/intersection/81073/6 "2019-03-29T18:36:01Z")

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But also some are missing, right? Here I also get one of the squares joined to the vertical… - bad object.

-Pascal

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<div class="post-metadata">

**Author:** ![encephalon](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/encephalon/32/611970_2.png) [@encephalon](https://discourse.mcneel.com/u/encephalon)\
**Post date:** [March 29, 2019, 6:38pm UTC](https://discourse.mcneel.com/t/intersection/81073/7 "2019-03-29T18:38:10Z")

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hmm nope right through the entire ding dong (at least on my old macbookpro), but the lower square is indeed joined into the leg. real square dance.

 ![bad%20kitty](https://global.discourse-cdn.com/mcneel/original/3X/8/8/88b99826cdbf6ba3c3f906c41ebd7948aa7162e8.png)

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**Author:** ![Robb](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/robb/32/474290_2.png) [@Robb](https://discourse.mcneel.com/u/Robb)\
**Post date:** [April 1, 2019, 1:09am UTC](https://discourse.mcneel.com/t/intersection/81073/8 "2019-04-01T01:09:51Z")

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The input curves are totally straightforward. They consist of radii and linear curves. Nothing unusual there at all. I’ve done this sort of thing for a long time and am perplexed as this intersection problem has happened only a few times. I actually exported that intersection from a larger file, opened it on it’s own, checked for bad surfaces, found none and still could not intersect , trim or boolean union. My intent was to have the two pieces of trim join at a 90 degree corner on the top surface of a hanging locker, bureau, chest of drawers and the like. The work around was easy: Setting ortho as an option with 45 degrees, I drew a orthogonal curve away from the corner of the object that the trim would rest upon, then drew a vertical straight curve, swept them and trimmed both objects to the temporary plane.

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**Author:** ![jeremy5](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/jeremy5/32/493741_2.png) [@jeremy5](https://discourse.mcneel.com/u/jeremy5)\
**Post date:** [April 2, 2019, 10:50am UTC](https://discourse.mcneel.com/t/intersection/81073/9 "2019-04-02T10:50:58Z")

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I might be missing something, but I can split and trim the OP’s example without problems:

![image](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/6/8/68605f57c62c20e8f0849aaa39be67121b24c865.png)  
(exploded to show components left)

Rhino 6.14.19085.9141, 26/03/2019

Jeremy

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<div class="post-metadata">

**Author:** ![Robb](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/robb/32/474290_2.png) [@Robb](https://discourse.mcneel.com/u/Robb)\
**Post date:** [April 2, 2019, 7:26pm UTC](https://discourse.mcneel.com/t/intersection/81073/10 "2019-04-02T19:26:27Z")

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I’m still in Rhino V 5. I’m probably too old to wait for recent releases to truly stabilize, and am also in the throws of building a new CAD workstation with the latest AMD threadripper CPU. So V 6 will have to wait. I’ve experienced the same problem in the past. It makes no sense to me that almost any other intersecting surfaces that apparently intersect will do so , but not these

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<div class="post-metadata">

**Author:** ![jeremy5](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/jeremy5/32/493741_2.png) [@jeremy5](https://discourse.mcneel.com/u/jeremy5)\
**Post date:** [April 2, 2019, 11:36pm UTC](https://discourse.mcneel.com/t/intersection/81073/11 "2019-04-02T23:36:00Z")

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How _did_ you draw those profile curves? I can’t reproduce the minimalist surfaces you got (but my noisier versions split in Rhino 5)  
 ![image](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/a/f/af252026a483b591fbcc6b708006933b4817eadf.png).

That said, whacking a diagonal line across the joint in the top view and trimming seems quicker and cleaner anyway.