# Need Help Adding Separate Geometry to a Curved Mesh Surface

**URL:** <https://discourse.mcneel.com/t/need-help-adding-separate-geometry-to-a-curved-mesh-surface/161537>\
**Category:** Grasshopper\
**Tags:** windows\
**Created:** [June 15, 2023, 9:41pm UTC](https://discourse.mcneel.com/t/need-help-adding-separate-geometry-to-a-curved-mesh-surface/161537 "2023-06-15T21:41:04Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![nicole.cater001](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/nicole.cater001/32/473828_2.png) [@nicole.cater001](https://discourse.mcneel.com/u/nicole.cater001)\
**Post date:** [June 15, 2023, 9:41pm UTC](https://discourse.mcneel.com/t/need-help-adding-separate-geometry-to-a-curved-mesh-surface/161537/1 "2023-06-15T21:41:04Z")

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Is there a way to add protruding geometry to a mesh? I tried using deconstruct brep to separate the grid I placed on my surface, but I want to add a series of spikes (which will be the additional 3d mass) to my surface.

[general shape.gh](https://discourse.mcneel.com/uploads/short-url/rkNZdMArd8MmgYkq3ZP465H9TWY.gh) (4.1 KB)  
[General shape.3dm](https://discourse.mcneel.com/uploads/short-url/9c0mG1RzxEspCYIjWW52UOwJghM.3dm) (51.3 KB)

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**Author:** ![Joseph\_Oster](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/joseph_oster/32/549124_2.png) [@Joseph\_Oster](https://discourse.mcneel.com/u/Joseph_Oster)\
**Post date:** [June 15, 2023, 10:04pm UTC](https://discourse.mcneel.com/t/need-help-adding-separate-geometry-to-a-curved-mesh-surface/161537/2 "2023-06-15T22:04:36Z")

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Why use TweenCrv ❓

Both Loft components in the purple group generate the same surface, with or without it.

 ![tween_loft](https://global.discourse-cdn.com/mcneel/uploads/default/original/4X/9/3/0/930de82cb2dc41f6ae5b0e3f4bb03092536a35f1.png)

Spikes ❓

**RELATED (DUPLICATE?) THREAD:**

> [@Combine two grasshopper to one file](https://discourse.mcneel.com/t/combine-two-grasshopper-to-one-file/161532):
>
> Hello, I was wondering if there’s some way to combine these two codes into one because I want it to seamless. Thank you for your help [general shape.gh](https://discourse.mcneel.com/uploads/short-url/rkNZdMArd8MmgYkq3ZP465H9TWY.gh) (4.1 KB) [erase.gh](https://discourse.mcneel.com/uploads/short-url/c1LWAdw0wrjETIEjMGVQ6cY02at.gh) (22.1 KB)