# Nodal values in FRD files

**URL:** <https://calculix.discourse.group/t/nodal-values-in-frd-files/2082>\
**Category:** Postprocessing/Visualization\
**Created:** [February 12, 2024, 4:26am UTC](https://calculix.discourse.group/t/nodal-values-in-frd-files/2082 "2024-02-12T04:26:15Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![kraviteja](https://avatars.discourse-cdn.com/v4/letter/k/bbe5ce/32.png) [@kraviteja](https://calculix.discourse.group/u/kraviteja)\
**Post date:** [February 12, 2024, 4:26am UTC](https://calculix.discourse.group/t/nodal-values-in-frd-files/2082/1 "2024-02-12T04:26:15Z")

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Hi All,

I have a question about the nodal values stored in the FRD file when using the \*EL FILE command. The manual for ccx2.18 says “This option is used to save selected element variables averaged at the nodal points in a frd file”. How are the averaged values calculated? What method is used to interpolate or extrapolate the values from integration points to the nodes?

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**Author:** ![Calc\_em](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\
**Post date:** [February 12, 2024, 8:02am UTC](https://calculix.discourse.group/t/nodal-values-in-frd-files/2082/2 "2024-02-12T08:02:56Z")

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This is done based on standard FEM procedures described in literature. You can check the book “The Finite Element Method for Three-Dimensional Thermomechanical Applications” by G. Dhondt (chapter 2.4. Extrapolation of Integration Point Values to the Nodes) which is considered a theory manual for CalculiX or just a generic book about FEM.