# Nonpositive Jacobian Determinant

**URL:** <https://prepomax.discourse.group/t/nonpositive-jacobian-determinant/2640>\
**Category:** General Questions\
**Created:** [April 20, 2025, 6:58pm UTC](https://prepomax.discourse.group/t/nonpositive-jacobian-determinant/2640 "2025-04-20T18:58:46Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Greyhound](https://avatars.discourse-cdn.com/v4/letter/g/e47774/32.png) [@Greyhound](https://prepomax.discourse.group/u/Greyhound)\
**Post date:** [April 20, 2025, 6:58pm UTC](https://prepomax.discourse.group/t/nonpositive-jacobian-determinant/2640/1 "2025-04-20T18:58:46Z")

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Hi,

I’m new to Prepomax (and quite new to FEA in general). I’m trying to model a buried pipeline, so in OnShape I created a simple cylinder shape, and when a cuboid with a boolean hole through the middle (I’ve since also tried to model the same in Blender, hoping I can manually create a simplier mesh - I realise this isn’t really the case).

Anyway, I’ve imported these 2 models into Prepomax, created meshes uses mostly default settings, although I have altered the min/max element sizes.

I’ve added materials, created a contact between the 2 mated surfaces, and then my BC’s and a simple load. But when I try and run the analysis I’m getting an error of ‘nonpositive jacobian determinant’. An element set was created and the problem was along the two contact surfaces.

I’m using v2.3.0, Windows 11.

Thanks all!  
James

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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 20, 2025, 7:50pm UTC](https://prepomax.discourse.group/t/nonpositive-jacobian-determinant/2640/2 "2025-04-20T19:50:25Z")

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Do you have adjustment enabled for contact ? If yes, try disabling it.