# Code development **URL:** https://calculix.discourse.group/c/code-development/15.md [Latest](https://calculix.discourse.group/latest.md) · [Categories](https://calculix.discourse.group/categories.md) --- ## [About the Code development category](https://calculix.discourse.group/t/about-the-code-development-category/3745)
**Author:** [@dhondt](https://calculix.discourse.group/u/dhondt)\ **Replies:** 0\ **Last updated:** [January 20, 2026, 1:01pm UTC](https://calculix.discourse.group/t/about-the-code-development-category/3745 "2026-01-20T13:01:14Z")
Discussions for contributors and developers working on the CalculiX solver codebase, including feature requests. --- ## [USER element : 1D beam custom implementation](https://calculix.discourse.group/t/user-element-1d-beam-custom-implementation/4079)
**Author:** [@p.viguier](https://calculix.discourse.group/u/p.viguier)\ **Replies:** 51\ **Last updated:** [October 7, 2026, 5:07am UTC](https://calculix.discourse.group/t/user-element-1d-beam-custom-implementation/4079 "2026-10-07T05:07:29Z")
Dear community, First a big thank to Guido Dhondt for such a beautiful software. I have been working recently to add a U1 user beam element with standard section. I ha seen that other user have started to work on thi… --- ## [CGX with rainbow desaturated colormaps](https://calculix.discourse.group/t/cgx-with-rainbow-desaturated-colormaps/4133)
**Author:** [@xyont](https://calculix.discourse.group/u/xyont)\ **Replies:** 0\ **Last updated:** [September 29, 2026, 6:03am UTC](https://calculix.discourse.group/t/cgx-with-rainbow-desaturated-colormaps/4133 "2026-09-29T06:03:24Z")
this is continued from previous discussion, i added rainbow desaturated colormaps since it widely used also. Modified part code extGL.c is placed at GitHub, unfortunately i cannot test since have no experiences in compil… --- ## [CalculiX and LIS solver](https://calculix.discourse.group/t/calculix-and-lis-solver/4130)
**Author:** [@rafal.brzegowy](https://calculix.discourse.group/u/rafal.brzegowy)\ **Replies:** 5\ **Last updated:** [September 28, 2026, 3:40am UTC](https://calculix.discourse.group/t/calculix-and-lis-solver/4130 "2026-09-28T03:40:14Z")
Hi everyone, I wanted to share a recent test project I’ve been working on. With the assistance of ChatGPT, I integrated the Lis (Library of Iterative Solvers for Linear Systems) solver into CalculiX (ccx) to test its pe… --- ## [CalculiX ccx, cgx and zstd compression](https://calculix.discourse.group/t/calculix-ccx-cgx-and-zstd-compression/4101)
**Author:** [@rafal.brzegowy](https://calculix.discourse.group/u/rafal.brzegowy)\ **Replies:** 4\ **Last updated:** [September 10, 2026, 2:15pm UTC](https://calculix.discourse.group/t/calculix-ccx-cgx-and-zstd-compression/4101 "2026-09-10T14:15:24Z")
I’d like to propose adding native zstd (Zstandard) compression support to both ccx and cgx. Using standard gzip or uncompressed files can be slow or storage-heavy. Integrating zstd directly gives us much faster compress… --- ## [Pyramid elements C3D5 & C3D13](https://calculix.discourse.group/t/pyramid-elements-c3d5-c3d13/1881)
**Author:** [@fgr](https://calculix.discourse.group/u/fgr)\ **Replies:** 32\ **Last updated:** [August 23, 2026, 10:54am UTC](https://calculix.discourse.group/t/pyramid-elements-c3d5-c3d13/1881 "2026-08-23T10:54:52Z")
I have been fiddling with implementing pyramid elements into ccx\_2.21 so it would be nice if anybody would help with any kind of testing of the elements. So far it’s only pure mechanical functionality in some unknown lim… --- ## [\*AMPLITUDE card enhancement: Mathematical expressions](https://calculix.discourse.group/t/amplitude-card-enhancement-mathematical-expressions/3947)
**Author:** [@johanngil](https://calculix.discourse.group/u/johanngil)\ **Replies:** 0\ **Last updated:** [May 21, 2026, 2:41pm UTC](https://calculix.discourse.group/t/amplitude-card-enhancement-mathematical-expressions/3947 "2026-05-21T14:41:04Z")
The attached development (https://www.dropbox.com/scl/fi/aznilolkoe92y8dsvyhil/Equation-Amplitudes.zip?rlkey=uu4coem4rxigirmuun5qdrwem&dl=0) enhances the current ccx \*AMPLITUDE functionality through an additional parame… --- ## [Acceleration output for dynamic calculations](https://calculix.discourse.group/t/acceleration-output-for-dynamic-calculations/2846)
**Author:** [@gmb](https://calculix.discourse.group/u/gmb)\ **Replies:** 19\ **Last updated:** [April 28, 2026, 6:58pm UTC](https://calculix.discourse.group/t/acceleration-output-for-dynamic-calculations/2846 "2026-04-28T18:58:33Z")
Hello! I’ve created a PR that adds the A option for \*NODE FILE to output the accelerations \[ACCE\] to the .frd file. As a beginner CalculiX user, I would appreciate some help constructing a simple verification example… --- ## [Using a custom user element (UEL)](https://calculix.discourse.group/t/using-a-custom-user-element-uel/3848)
**Author:** [@bruno.zilli](https://calculix.discourse.group/u/bruno.zilli)\ **Replies:** 31\ **Last updated:** [April 21, 2026, 9:22am UTC](https://calculix.discourse.group/t/using-a-custom-user-element-uel/3848 "2026-04-21T09:22:08Z")
Dear CalculiX community, Good morning! I hope this message finds you well. I am working on a custom user element (UEL) for a 3‑node beam element with 6 degrees of freedom per node. The compilation of CalculiX (version … --- ## [Exporting the final global stiffness matrix in CalculiX](https://calculix.discourse.group/t/exporting-the-final-global-stiffness-matrix-in-calculix/3879)
**Author:** [@aj\_warrier](https://calculix.discourse.group/u/aj_warrier)\ **Replies:** 2\ **Last updated:** [April 14, 2026, 7:57pm UTC](https://calculix.discourse.group/t/exporting-the-final-global-stiffness-matrix-in-calculix/3879 "2026-04-14T19:57:37Z")
Hi everyone, I am researching a composite beam modeling approach by comparing two cantilever setups: A baseline beam modeled entirely with C3D20 (20-node hexahedral) elements. A composite beam where S8 shell eleme… --- ## [Output reaction forces only](https://calculix.discourse.group/t/output-reaction-forces-only/3809)
**Author:** [@gmb](https://calculix.discourse.group/u/gmb)\ **Replies:** 56\ **Last updated:** [March 19, 2026, 7:57pm UTC](https://calculix.discourse.group/t/output-reaction-forces-only/3809 "2026-03-19T19:57:43Z")
Hi! This topic mentions that the curren RF key of \*NODE PRINT outputs both reaction forces and point loads. I’ve created a PR that introduces RR, which outputs only the reaction forces. I’ve created some validation sa… --- ## [Beam section keywords to support wide flanges (I or H)](https://calculix.discourse.group/t/beam-section-keywords-to-support-wide-flanges-i-or-h/3810)
**Author:** [@xyont](https://calculix.discourse.group/u/xyont)\ **Replies:** 2\ **Last updated:** [March 9, 2026, 5:34pm UTC](https://calculix.discourse.group/t/beam-section-keywords-to-support-wide-flanges-i-or-h/3810 "2026-03-09T17:34:31Z")
hi, wide flange (I or H) section is commonly used in steel structure but is not available and supported unfortunately. It seems can be really useful when CalculiX beam section capable to analysis this type of beams, than… --- ## [Something like \*MODAL PRINT](https://calculix.discourse.group/t/something-like-modal-print/2881)
**Author:** [@Layson](https://calculix.discourse.group/u/Layson)\ **Replies:** 4\ **Last updated:** [September 24, 2025, 7:23am UTC](https://calculix.discourse.group/t/something-like-modal-print/2881 "2025-09-24T07:23:12Z")
Hi, I’m currently studying Fliud-Structure Interaction and using calculix coupled with other fluid solver to solve aeroelasticity problems. I’m new to calculix, so I cannot output my desired results through editting inpu… --- ## [Modifying mechanical strain and stress for a multiscale application](https://calculix.discourse.group/t/modifying-mechanical-strain-and-stress-for-a-multiscale-application/2853)
**Author:** [@ishaandesai](https://calculix.discourse.group/u/ishaandesai)\ **Replies:** 3\ **Last updated:** [September 2, 2025, 7:30am UTC](https://calculix.discourse.group/t/modifying-mechanical-strain-and-stress-for-a-multiscale-application/2853 "2025-09-02T07:30:29Z")
Hello, I am trying to couple CalculiX to a micro-mechanics solver to do a two-scale FE2 simulations. The coupling itself is done via the coupling library preCICE, which has been used to couple FSI or CHT type scenarios … --- ## [CalculiX source code repository](https://calculix.discourse.group/t/calculix-source-code-repository/84)
**Author:** [@benzwick](https://calculix.discourse.group/u/benzwick)\ **Replies:** 5\ **Last updated:** [July 28, 2025, 8:26am UTC](https://calculix.discourse.group/t/calculix-source-code-repository/84 "2025-07-28T08:26:26Z")
Is there an official source code repository for CalculiX where users can check what has been changed and submit pull requests, issues etc.? EDIT: I just realised that this was already answered here: Build failures with … --- ## [\[closed\]\*EL PRINT request](https://calculix.discourse.group/t/closed-el-print-request/2765)
**Author:** [@Paul18fr](https://calculix.discourse.group/u/Paul18fr)\ **Replies:** 2\ **Last updated:** [June 14, 2025, 7:25pm UTC](https://calculix.discourse.group/t/closed-el-print-request/2765 "2025-06-14T19:25:47Z")
Hi Except if i’m mistaken, there’s not “REQUEST” section to suggest ccx improvements ; as described in a prepomax topic, \*El print allows to output stress data, but only tensor components: in my opinion equivalent/princ… --- ## [CalculiX patch for VTK output (for an info)](https://calculix.discourse.group/t/calculix-patch-for-vtk-output-for-an-info/295)
**Author:** [@xyont](https://calculix.discourse.group/u/xyont)\ **Replies:** 4\ **Last updated:** [November 14, 2020, 1:03am UTC](https://calculix.discourse.group/t/calculix-patch-for-vtk-output-for-an-info/295 "2020-11-14T01:03:03Z")
hi, i just found an interesting new project at GitHub, is a patch for CalculiX to VTK output formats. did not try yet, since i’m not expert in deployment. CalculiX has many supported mesh format to export (e.g Nastran,…