# Boundary Conditions - Half of a cylinder

**URL:** <https://prepomax.discourse.group/t/boundary-conditions-half-of-a-cylinder/1688>\
**Category:** General Questions\
**Created:** [April 18, 2024, 10:53am UTC](https://prepomax.discourse.group/t/boundary-conditions-half-of-a-cylinder/1688 "2024-04-18T10:53:44Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Max](https://avatars.discourse-cdn.com/v4/letter/m/e5b9ba/32.png) [@Max](https://prepomax.discourse.group/u/Max)\
**Post date:** [April 18, 2024, 10:53am UTC](https://prepomax.discourse.group/t/boundary-conditions-half-of-a-cylinder/1688/1 "2024-04-18T10:53:44Z")

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Hello everybody,  
I have a quick question about the boundary conditions. I cant seem to find the right tool to fix (all DOF to 0) the bottom half of my cylinder (pictures attached with the area marked in red). The only way i can think of is to create a surface in which i select each node inidivdually and the fix that surface but there has to be a better way?

Thanks in advance.  
Greetings  
 ![view_one](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/2/231e53c13fb4e1dd0dd0948ce2682d36a493aa70.png)

 ![view_two](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/c/cefbd41dd4d191fe2043b7930f51a93d526ea43a.png)

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**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [April 18, 2024, 11:07am UTC](https://prepomax.discourse.group/t/boundary-conditions-half-of-a-cylinder/1688/2 "2024-04-18T11:07:07Z")

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It would be best to have a surface partition prepared in CAD before importing to PrePoMax but you can also just create a node set using the _Face angle_ (if only the surface nodes should be selected) and _Node_ modes of _FE mesh based selection_ and drag the selection box over that half of the cylinder.

![select nodes](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/9/906fbfc79c38411085a21fe90725e4c05074f9bc.gif)

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<div class="post-metadata">

**Author:** ![Max](https://avatars.discourse-cdn.com/v4/letter/m/e5b9ba/32.png) [@Max](https://prepomax.discourse.group/u/Max)\
**Post date:** [April 18, 2024, 11:44am UTC](https://prepomax.discourse.group/t/boundary-conditions-half-of-a-cylinder/1688/3 "2024-04-18T11:44:37Z")

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Thank you very much.