# Offsetsrf failure on complex polysurface

**URL:** <https://discourse.mcneel.com/t/offsetsrf-failure-on-complex-polysurface/41510>\
**Category:** Rhino for Mac\
**Created:** [February 21, 2017, 12:35pm UTC](https://discourse.mcneel.com/t/offsetsrf-failure-on-complex-polysurface/41510 "2017-02-21T12:35:01Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Rowan1](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/rowan1/32/54302_2.png) [@Rowan1](https://discourse.mcneel.com/u/Rowan1)\
**Post date:** [February 21, 2017, 12:35pm UTC](https://discourse.mcneel.com/t/offsetsrf-failure-on-complex-polysurface/41510/1 "2017-02-21T12:35:01Z")

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Oke guys, I need help concerning offsetSrf. I designed a device curved to follow the shoulders. For prototyping I am going to cast a silicone cover with a thickness of 1 mm. So what I need to do is model a mold, and for that **I need to offset the entire device uniformly with 1 mm**. (and also a version with 5 mm)  
Offsets that I tried get holes or messed up surfaces and therefore are hollow (I know, the model I made is quite messy…) It needs to be a solid as I need to booleandifference it inside a cube to get a mold.  
Scaling does not work as I do not get a uniform layer of 1 mm. Neither does Shell or offsetmesh and other things that I tried.  
As the device is already 3D printed, I cannot make a lot of changes to the base model.

Is there any way to clean up the polysurface and/or make the offset work?

[Lia for mold.3dm](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/1/5/1551e389920b38e4e2f8a443726a9153a1333c5a.3dm) (10.0 MB)

You would save the day of a young product designer!  
Rowan~

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**Author:** ![milezee](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/milezee/32/522471_2.png) [@milezee](https://discourse.mcneel.com/u/milezee)\
**Post date:** [February 21, 2017, 12:53pm UTC](https://discourse.mcneel.com/t/offsetsrf-failure-on-complex-polysurface/41510/2 "2017-02-21T12:53:20Z")

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I’m not particularly knowledgeable with 3d printing, and that file sure is big ! Have you tried individually offsetting the 3 different parts, it worked on my machine, the end end sections took a minute or 2 to offset, the junctions where the ends meet the central section looked like they may need cleaning up though

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**Author:** ![Rowan1](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/rowan1/32/54302_2.png) [@Rowan1](https://discourse.mcneel.com/u/Rowan1)\
**Post date:** [February 21, 2017, 1:11pm UTC](https://discourse.mcneel.com/t/offsetsrf-failure-on-complex-polysurface/41510/3 "2017-02-21T13:11:16Z")

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Yeah I know it is big, it needed to be bent over the 3D file of a torso to fit.  
And yes I also tried that. Even dividing the end section in parts. Actually that junction area that you mentioned where the device narrows down is indeed where the issues are. There are 4 missing surfaces in the resulting offset. I do want to clean up the model there but as far as I know I cannot create edit points on a polysurface… Is this possible?

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**Author:** ![milezee](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/milezee/32/522471_2.png) [@milezee](https://discourse.mcneel.com/u/milezee)\
**Post date:** [February 21, 2017, 1:28pm UTC](https://discourse.mcneel.com/t/offsetsrf-failure-on-complex-polysurface/41510/4 "2017-02-21T13:28:39Z")

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personally I’d rebuild it, it looks ever so messy