# More Boolean issues with two closed polysurfaces

**URL:** <https://discourse.mcneel.com/t/more-boolean-issues-with-two-closed-polysurfaces/28229>\
**Category:** Rhino for Mac\
**Created:** [January 10, 2016, 9:19pm UTC](https://discourse.mcneel.com/t/more-boolean-issues-with-two-closed-polysurfaces/28229 "2016-01-10T21:19:55Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![Revel\_Woodard](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/revel_woodard/32/663827_2.png) [@Revel\_Woodard](https://discourse.mcneel.com/u/Revel_Woodard)\
**Post date:** [January 10, 2016, 9:19pm UTC](https://discourse.mcneel.com/t/more-boolean-issues-with-two-closed-polysurfaces/28229/1 "2016-01-10T21:19:56Z")

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I am trying to boolean these two objects and it is not working. Presumably this is because there are shared faces. Do I really need to go around and delete all the shared faces or is there an easier way to join these two objects?

-rev

[Boolean\_union\_test.3dm](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/3/2/32af65fcaca270d28c38a24bb9f1839822244792.3dm) (2.5 MB)

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**Author:** ![0netech](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/0netech/32/384385_2.png) [@0netech](https://discourse.mcneel.com/u/0netech)\
**Post date:** [January 10, 2016, 11:44pm UTC](https://discourse.mcneel.com/t/more-boolean-issues-with-two-closed-polysurfaces/28229/2 "2016-01-10T23:44:14Z")

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Most likely that is because one of them is not a closed polysurface (not a solid). I added a missing surface, trimmed a little, and joined it back. Now Boolean should work.

[Boolean\_union\_test.3dm](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/7/0/70b408179bc498cdf93d0d4f0fa16d3275b9bd89.3dm) (2.5 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:** [January 11, 2016, 12:51am UTC](https://discourse.mcneel.com/t/more-boolean-issues-with-two-closed-polysurfaces/28229/3 "2016-01-11T00:51:21Z")

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Hi Revel - the larger object is not valid (SelBadObjects)

- try:

ExtractBadSrf.  
DupBorder  
Delete the surface  
Select the curves from DupBorder  
PlanarSrf  
Join it back into the object, run Check to verify.

But, the Boolean is still unlikely to work - it did not, here. The easy way out is probably to ExtractSrf & Delete all the coincident faces and then simply Join the two parts.

-Pascal

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<div class="post-metadata">

**Author:** ![Revel\_Woodard](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/revel_woodard/32/663827_2.png) [@Revel\_Woodard](https://discourse.mcneel.com/u/Revel_Woodard)\
**Post date:** [January 11, 2016, 3:16am UTC](https://discourse.mcneel.com/t/more-boolean-issues-with-two-closed-polysurfaces/28229/4 "2016-01-11T03:16:06Z")

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> [@pascal](#):
>
> ExtractSrf & Delete all the coincident faces and then simply Join the two parts.

Thank you, Pascal. I have two valid polysurfaces, but, how do I do the above?

Best,

-Revel

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<div class="post-metadata">

**Author:** ![Revel\_Woodard](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/revel_woodard/32/663827_2.png) [@Revel\_Woodard](https://discourse.mcneel.com/u/Revel_Woodard)\
**Post date:** [February 5, 2016, 7:33pm UTC](https://discourse.mcneel.com/t/more-boolean-issues-with-two-closed-polysurfaces/28229/5 "2016-02-05T19:33:44Z")

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could you take another look at this, and / or describe to me how to go about joining these?

I tried deleting all coincident faces, and then joining, to no avail.

Best,

-Rev

[3 closed polysrf.3dm](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/f/8/f833ba7598bb84bcc11740abeaa93c344a98c166.3dm) (3.7 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:** [February 5, 2016, 7:48pm UTC](https://discourse.mcneel.com/t/more-boolean-issues-with-two-closed-polysurfaces/28229/6 "2016-02-05T19:48:47Z")

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Hi Revel - it looks to me like it all hooks up if you remove the coincident faces, except in a couple of locations - seems to be very slightly offset here:

 ![](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/3/0/304c8e40ca14b2efe21f8b897826cfa5e966683d.png)

Also, many of the surfaces that are chopped up into the three pieces are the same surfaces and can be untrimmed and retrimmed to avoid the seams where the three parts go together. I don’t know if it is with the effort but just so you know…

-Pascal

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<div class="post-metadata">

**Author:** ![Revel\_Woodard](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/revel_woodard/32/663827_2.png) [@Revel\_Woodard](https://discourse.mcneel.com/u/Revel_Woodard)\
**Post date:** [February 5, 2016, 8:04pm UTC](https://discourse.mcneel.com/t/more-boolean-issues-with-two-closed-polysurfaces/28229/7 "2016-02-05T20:04:56Z")

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Yes, I am at the same stage here, see attached model. So in the case where you have two curves slightly offset like that, what is the best recourse? PlanarSrf? SrfPt? Cap?

Thanks!

-R

[3 closed polysrf(joined).3dm](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/4/b/4b75b721d4c3686b24d9b1e5e0039a82ef6d71e0.3dm) (2.5 MB)this case

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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:** [February 5, 2016, 8:58pm UTC](https://discourse.mcneel.com/t/more-boolean-issues-with-two-closed-polysurfaces/28229/8 "2016-02-05T20:58:09Z")

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I guess the easiest is to extract all the surfaces to the right, Move them, snapping to end points to close the gap on the left. That opens a gap to the right, but the surfaces there all appear to be linear in the side-to-side direction, so you can move the edges of the main object’s surfaces that are there over. (Sub object select the edges, Command-Shift click or window.)

[3 closed polysrf\_PG.3dm](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/d/d/dd1bc8bd1727a394b06ed85352ceb9e79c29c229.3dm) (2.7 MB)

-Pascal