# Isotrim help

**URL:** <https://discourse.mcneel.com/t/isotrim-help/84227>\
**Category:** Grasshopper\
**Created:** [June 3, 2019, 3:14pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227 "2019-06-03T15:14:08Z")\
**Posts on this page:** 20\
**Page:** 1

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**Author:** ![geigera](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/geigera/32/158347_2.png) [@geigera](https://discourse.mcneel.com/u/geigera)\
**Post date:** [June 3, 2019, 3:14pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/1 "2019-06-03T15:14:08Z")

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Hello new user.

Here is what I am trying to do. I want to create a series of split surfaces on this surface with regards to the openings on that surface. I’d like to be able to choose the spacing as well. So that I can bake them and pull dimensional data off of. Every time I isotrim the surface it disregards the boundary. I’m probably going about this all wrong, like I said I’m new and I would be so grateful for some help Thanks in advance!

 ![Capture%202](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/9/5/9580eebbfffcf175e45e2f5bd1016454b80a4750.png)

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**Author:** ![Michael\_Pryor](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/michael_pryor/32/489117_2.png) [@Michael\_Pryor](https://discourse.mcneel.com/u/Michael_Pryor)\
**Post date:** [June 3, 2019, 3:22pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/2 "2019-06-03T15:22:48Z")

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Isotrim works on the underlying surface, not trimmed surfaces (breps). Do a quick search you will see this question asked a lot.

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**Author:** ![geigera](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/geigera/32/158347_2.png) [@geigera](https://discourse.mcneel.com/u/geigera)\
**Post date:** [June 3, 2019, 3:31pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/4 "2019-06-03T15:31:40Z")

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So in order for this to work I should be using breps instead?

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**Author:** ![Michael\_Pryor](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/michael_pryor/32/489117_2.png) [@Michael\_Pryor](https://discourse.mcneel.com/u/Michael_Pryor)\
**Post date:** [June 3, 2019, 3:32pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/5 "2019-06-03T15:32:57Z")

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No, you are using a Brep already. A trimmed surface is a Brep. You should do what you did, then trim the result sub surfaces with the boundary outlines. Search the forum for isotrim trimmed surface.

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**Author:** ![geigera](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/geigera/32/158347_2.png) [@geigera](https://discourse.mcneel.com/u/geigera)\
**Post date:** [June 3, 2019, 3:33pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/6 "2019-06-03T15:33:52Z")

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Thanks for your help!

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**Author:** ![PeterFotiadis](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/peterfotiadis/32/472316_2.png) [@PeterFotiadis](https://discourse.mcneel.com/u/PeterFotiadis)\
**Post date:** [June 3, 2019, 3:50pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/7 "2019-06-03T15:50:43Z")

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See attached. Notify if you need some elaboration more with regard the output.

[BrepFace\_IsoCurves\_V1.3dm](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/d/d/dd73a1dba2b383ad6755d92a4a00487f31c53add.3dm) (162.1 KB)  
[BrepFace\_IsoCurves\_V1.gh](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/e/b/eb4b72d6692c222cd3db5d351f13dbdd56fac68e.gh) (6.5 KB)

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**Author:** ![geigera](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/geigera/32/158347_2.png) [@geigera](https://discourse.mcneel.com/u/geigera)\
**Post date:** [June 3, 2019, 4:09pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/8 "2019-06-03T16:09:02Z")

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This works great thanks! I’d like to ask your help in taking it a little further.  
I want to be able to plug in a surface from rhino, (these surfaces would have openings for windows and doors) and I’d like to be able to create panels that will have their positioning/size/spacing be determined automatically around the openings in the facade.Ideally having sliders that we could change all of those setting depending on the job.

That’s a lot to ask, I’m sorry, I’m just a little over my head here.

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**Author:** ![PeterFotiadis](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/peterfotiadis/32/472316_2.png) [@PeterFotiadis](https://discourse.mcneel.com/u/PeterFotiadis)\
**Post date:** [June 3, 2019, 4:28pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/9 "2019-06-03T16:28:11Z")

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That’s rather easy (as an Academic puzzle for students) and/or very complex (in the ugly part of life: i.e. the real-life [plus using **BIM meta-data** etc etc]) : just ask from a friend - who (cross fingers) knows a thing or two about final level of studies - to provide some **1:1 details** on facades (and spot what happens “around” the openings boundaries, the type of facade, the available standard sizes … blah, blah).

But if we stay in the Academic aspect of things the issue here is that I work via code and I don’t use native components. So … you’ll receive a black box that …er … would remain a black box for ever.

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**Author:** ![geigera](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/geigera/32/158347_2.png) [@geigera](https://discourse.mcneel.com/u/geigera)\
**Post date:** [June 3, 2019, 4:36pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/10 "2019-06-03T16:36:52Z")

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Those real life things aren’t necessarily all that complex generally speaking, with aluminum paneling, their spacing and size is relatively limited. Looking at the GH file you gave me, would I be able to generate those conditions off of the isocurvetree?

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**Author:** ![PeterFotiadis](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/peterfotiadis/32/472316_2.png) [@PeterFotiadis](https://discourse.mcneel.com/u/PeterFotiadis)\
**Post date:** [June 3, 2019, 4:44pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/11 "2019-06-03T16:44:10Z")

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Are you after an Alucobond type of facade? Say following a typical layout like this?

![Screen%20Shot%20059](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/c/2/c200506ea371a755ea0b6d88831f65957fa16b3b.jpeg)

BTW: Obviously we are talking modules here and not just curves like the ones in the tree. Plus stuff having some remote relation with reality around the openings. Like:

![Screen%20Shot%20060](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/5/a/5a5f1efa8aa46760fee2bb7654bdb11cc4eabd91.jpeg)

So in general you need 20-25 cm space as follows: 40 cm for the panels/fasteners, around 60 cm for a proper fully adjustable support system plus 10 cm for some decent thermal insulation (the best by 1M miles: **Foamglas** [with one s]).

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**Author:** ![geigera](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/geigera/32/158347_2.png) [@geigera](https://discourse.mcneel.com/u/geigera)\
**Post date:** [June 3, 2019, 4:48pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/12 "2019-06-03T16:48:55Z")

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That looks about right! The joint is varied between panel types. Ideally I’d like to generate a layout similar to this

 ![image](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/8/4/845bd76589df31e5801565afdb7a85b530b0ec43.jpeg)

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**Author:** ![akilli](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/akilli/32/514967_2.png) [@akilli](https://discourse.mcneel.com/u/akilli)\
**Post date:** [June 3, 2019, 4:53pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/13 "2019-06-03T16:53:31Z")

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Not being an architect, I always wonder what the chances are replacement parts for these elaborate systems will exist in 10 or 20 years? Or will they be grown in a vat by that time?

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**Author:** ![geigera](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/geigera/32/158347_2.png) [@geigera](https://discourse.mcneel.com/u/geigera)\
**Post date:** [June 3, 2019, 4:56pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/14 "2019-06-03T16:56:32Z")

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Some of these products have twice that lifespan, suitable for just about any external conditions you could think of.

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**Author:** ![PeterFotiadis](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/peterfotiadis/32/472316_2.png) [@PeterFotiadis](https://discourse.mcneel.com/u/PeterFotiadis)\
**Post date:** [June 3, 2019, 4:56pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/15 "2019-06-03T16:56:46Z")

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My dear Watson: I consume therefore I am.

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**Author:** ![akilli](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/akilli/32/514967_2.png) [@akilli](https://discourse.mcneel.com/u/akilli)\
**Post date:** [June 3, 2019, 5:03pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/16 "2019-06-03T17:03:01Z")

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Well, to my mind, that’s still not a long period of time, especially considering how many of these similar elements are required in some modern structures, only increasing the chance of failure.The sprawling “luxury” rental right across the street from me was built 7 years ago and already needed all its large windows to be completely recaulked.

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**Author:** ![geigera](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/geigera/32/158347_2.png) [@geigera](https://discourse.mcneel.com/u/geigera)\
**Post date:** [June 3, 2019, 5:06pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/17 "2019-06-03T17:06:56Z")

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Unfortunately that is quite common. My hope in GH is to be able to automate certain processes that are still being done by hand. We use a cnc machine to cut the these panels, so being able to pull dimensional data off baked geometry with regards to panel spacing would be incredibly helpful.

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**Author:** ![Michael\_Pryor](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/michael_pryor/32/489117_2.png) [@Michael\_Pryor](https://discourse.mcneel.com/u/Michael_Pryor)\
**Post date:** [June 3, 2019, 5:11pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/18 "2019-06-03T17:11:47Z")

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By that time the building will probably be torn down and a new one put in its place, buildings don’t stay as long as they used to 😃

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**Author:** ![geigera](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/geigera/32/158347_2.png) [@geigera](https://discourse.mcneel.com/u/geigera)\
**Post date:** [June 3, 2019, 5:16pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/19 "2019-06-03T17:16:25Z")

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So getting back at it. How do I get from the isocurvetree to a surface that can variate in the ways that I’ve mentioned?

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**Author:** ![akilli](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/akilli/32/514967_2.png) [@akilli](https://discourse.mcneel.com/u/akilli)\
**Post date:** [June 3, 2019, 5:34pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/20 "2019-06-03T17:34:26Z")

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That’s the sad, unstated truth. If nothing’s meant to last, then why don’t we just live in tents?

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**Author:** ![geigera](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/geigera/32/158347_2.png) [@geigera](https://discourse.mcneel.com/u/geigera)\
**Post date:** [June 3, 2019, 5:34pm UTC](https://discourse.mcneel.com/t/isotrim-help/84227/21 "2019-06-03T17:34:45Z")

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It doesn’t necessarily have to be a complex script, I was just looking to gather basic information that could be passed on to our guys doing prefab.

[Next page](https://discourse.mcneel.com/t/isotrim-help/84227.md?page=2)