# Duplicate elements lead to non display of elements in result presentation

**URL:** <https://prepomax.discourse.group/t/duplicate-elements-lead-to-non-display-of-elements-in-result-presentation/1777>\
**Category:** Bug Reports\
**Created:** [May 30, 2024, 8:02am UTC](https://prepomax.discourse.group/t/duplicate-elements-lead-to-non-display-of-elements-in-result-presentation/1777 "2024-05-30T08:02:45Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![febing](https://avatars.discourse-cdn.com/v4/letter/f/c89c15/32.png) [@febing](https://prepomax.discourse.group/u/febing)\
**Post date:** [May 30, 2024, 8:02am UTC](https://prepomax.discourse.group/t/duplicate-elements-lead-to-non-display-of-elements-in-result-presentation/1777/1 "2024-05-30T08:02:45Z")

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Hello,  
i created a model with “gostelements”. They have the same nodes as existing elements,  
but a very low stiffness material. The model runs wothout problems in ccx. When i read the  
result file in PrePoMax, the elements that have “duplicates” and there duplicates are invisible  
in result presentation.  
[wurfel.inp](https://prepomax.discourse.group/uploads/short-url/tbkfz04fmw7SNOhrJ0mzdjNOXCL.inp) (11.0 KB)

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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:** [May 30, 2024, 10:38am UTC](https://prepomax.discourse.group/t/duplicate-elements-lead-to-non-display-of-elements-in-result-presentation/1777/2 "2024-05-30T10:38:49Z")

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I wouldn’t say it’s a bug. GraphiX (native pre- and postprocessor of CalculiX) can’t display those results either. Same with FreeCAD.

What do you want to model this way ? Why are you using this approach ?

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<div class="post-metadata">

**Author:** ![febing](https://avatars.discourse-cdn.com/v4/letter/f/c89c15/32.png) [@febing](https://prepomax.discourse.group/u/febing)\
**Post date:** [May 31, 2024, 12:56pm UTC](https://prepomax.discourse.group/t/duplicate-elements-lead-to-non-display-of-elements-in-result-presentation/1777/3 "2024-05-31T12:56:21Z")

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I am simulating a layer by layer build up of a metal part. The elements are first removed with \*Model Change, el, remove. Than ever layer is added with Model Change, el, Add. The existing elements undergo a deformation. So the nodes at the boundary to the next, not yet added elements move away from this elements. This leads to severe distortion of the not yet added elements. With ADD=Strain Free CCX adds inherent stress to that elements in the moment of adding, so that, despite the distorted shape, the elements are stress free. This means the elements are added in distorted shape. But this is not what i want. The elements should be added with there original size. If i use “ghostelements” that are not removed, this elements “pull” the removed elements with the away moving, deformed elements. By the way, this technique is suggested by the ABAQUS manual entry to \*Model Change!

With Add=With Strain ccx adds no inherent stress, that neutralizes the stresses due to distortion. In this case the calculation does not converge, due to the severe distortions and the high stress (plastic material).