# Model setup **URL:** https://calculix.discourse.group/c/model-setup/9.md [Latest](https://calculix.discourse.group/latest.md) · [Categories](https://calculix.discourse.group/categories.md) --- ## [About the Model setup category](https://calculix.discourse.group/t/about-the-model-setup-category/3739)
**Author:** [@dhondt](https://calculix.discourse.group/u/dhondt)\ **Replies:** 0\ **Last updated:** [January 20, 2026, 12:55pm UTC](https://calculix.discourse.group/t/about-the-model-setup-category/3739 "2026-01-20T12:55:37Z")
Defining geometry, meshes, materials, boundary conditions, loads, steps, and preparing input files for analysis. --- ## [Unitless FE solvers](https://calculix.discourse.group/t/unitless-fe-solvers/1804)
**Author:** [@Disla](https://calculix.discourse.group/u/Disla)\ **Replies:** 6\ **Last updated:** [September 26, 2026, 3:04pm UTC](https://calculix.discourse.group/t/unitless-fe-solvers/1804 "2026-09-26T15:04:52Z")
Hi, If ccx is a unitless FE solver, ¿how does it determine the default values and their units to be consistent with the model units?. As an example , ¿How should one read D1 known that it has pressure units? \*WARNING … --- ## [Calculix equivalent to Ansys force bonded](https://calculix.discourse.group/t/calculix-equivalent-to-ansys-force-bonded/4108)
**Author:** [@linth](https://calculix.discourse.group/u/linth)\ **Replies:** 2\ **Last updated:** [September 15, 2026, 9:57am UTC](https://calculix.discourse.group/t/calculix-equivalent-to-ansys-force-bonded/4108 "2026-09-15T09:57:05Z")
Hi there, Ansys provides ways to treat contact different in a prestressed modal analysis in different ways: true status (e.g. if sliding in static, than only normal contact stiffness is used in the modal analysis, if … --- ## [Calculix sometimes converging](https://calculix.discourse.group/t/calculix-sometimes-converging/4103)
**Author:** [@Mishal](https://calculix.discourse.group/u/Mishal)\ **Replies:** 1\ **Last updated:** [September 8, 2026, 9:20am UTC](https://calculix.discourse.group/t/calculix-sometimes-converging/4103 "2026-09-08T09:20:19Z")
Hi Guys Please refer to the link for the .inp file. The simulation presents a connection where one location has a slotted hole. I am applying a fairly low pretension of 8kN on the bolts over 3 seconds, there is then 2 … --- ## [The Mohr-Coulomb constitutive model & linear surface-to-surface contact](https://calculix.discourse.group/t/the-mohr-coulomb-constitutive-model-linear-surface-to-surface-contact/4077)
**Author:** [@pzu4](https://calculix.discourse.group/u/pzu4)\ **Replies:** 17\ **Last updated:** [August 14, 2026, 1:42pm UTC](https://calculix.discourse.group/t/the-mohr-coulomb-constitutive-model-linear-surface-to-surface-contact/4077 "2026-08-14T13:42:59Z")
I have observed an unusual phenomenon: when the Mohr-Coulomb constitutive model is combined with linear surface-to-surface contact in CalculiX, the model fails to converge. After replacing the linear contact definition w… --- ## [Soil-pipe interaction analysis](https://calculix.discourse.group/t/soil-pipe-interaction-analysis/4078)
**Author:** [@Juseche](https://calculix.discourse.group/u/Juseche)\ **Replies:** 2\ **Last updated:** [July 30, 2026, 10:26am UTC](https://calculix.discourse.group/t/soil-pipe-interaction-analysis/4078 "2026-07-30T10:26:42Z")
Hi! This is a model for soil-pipe interaction analysis. It is experiencing convergence issues; what is the best way to model this problem? The link to the INP file is as follows: Thanks in advance. --- ## [\*RESTART for aeroelastic analysis](https://calculix.discourse.group/t/restart-for-aeroelastic-analysis/4075)
**Author:** [@yolk](https://calculix.discourse.group/u/yolk)\ **Replies:** 3\ **Last updated:** [July 26, 2026, 8:07am UTC](https://calculix.discourse.group/t/restart-for-aeroelastic-analysis/4075 "2026-07-26T08:07:48Z")
Hi all, I’m trying to set up a nonlinear optimization with CalculiX and a custom aerodynamic solver. In the optimization loop, because stiffness is dependent on deformation, I have to do the following loop: Run aero Ap… --- ## [NAN in Pardiso solver( the penalty contact method )](https://calculix.discourse.group/t/nan-in-pardiso-solver-the-penalty-contact-method/4045)
**Author:** [@pzu4](https://calculix.discourse.group/u/pzu4)\ **Replies:** 9\ **Last updated:** [July 20, 2026, 2:33am UTC](https://calculix.discourse.group/t/nan-in-pardiso-solver-the-penalty-contact-method/4045 "2026-07-20T02:33:12Z")
I am running a static analysis with CalculiX (CCX). I first modeled the bonded interface using the \*TIE constraint, but the results were unsatisfactory. I then switched to the penalty contact method instead. However, the… --- ## [Axial forces in beams & trusses](https://calculix.discourse.group/t/axial-forces-in-beams-trusses/4051)
**Author:** [@WP\_316](https://calculix.discourse.group/u/WP_316)\ **Replies:** 1\ **Last updated:** [July 13, 2026, 4:16pm UTC](https://calculix.discourse.group/t/axial-forces-in-beams-trusses/4051 "2026-07-13T16:16:59Z")
Hello, Very boring question, but tearing my hair out over it. How to I get axial force values out of beams and trusses? I need to post-process the figures, so need them in the .dat from \*Node Print. Section forces seem… --- ## [How to model elastic spring back](https://calculix.discourse.group/t/how-to-model-elastic-spring-back/2811)
**Author:** [@Juseche](https://calculix.discourse.group/u/Juseche)\ **Replies:** 14\ **Last updated:** [July 13, 2026, 2:32pm UTC](https://calculix.discourse.group/t/how-to-model-elastic-spring-back/2811 "2026-07-13T14:32:49Z")
Hi I simulated the forming process of a metal plate (considering plasticity and large displacements) by incrementally imposing a displacement field on the plate. This simulation works well. Now, how do I simulate the pl… --- ## [Explicit Dynamic Analysis Cube on a Thin Plate](https://calculix.discourse.group/t/explicit-dynamic-analysis-cube-on-a-thin-plate/4049)
**Author:** [@Peter](https://calculix.discourse.group/u/Peter)\ **Replies:** 1\ **Last updated:** [July 11, 2026, 5:05pm UTC](https://calculix.discourse.group/t/explicit-dynamic-analysis-cube-on-a-thin-plate/4049 "2026-07-11T17:05:19Z")
Dear all, I’m new to CalculiX and am trying to run an EXPLICIT DYNAMIC SIMULATION using CalculiX. The simulation involves the impact of a cube on a thin plate. What I get is a strange trajectory of the cube, which doesn… --- ## [3D Simulation of 2D Geometries](https://calculix.discourse.group/t/3d-simulation-of-2d-geometries/4022)
**Author:** [@James\_G](https://calculix.discourse.group/u/James_G)\ **Replies:** 5\ **Last updated:** [June 27, 2026, 3:52pm UTC](https://calculix.discourse.group/t/3d-simulation-of-2d-geometries/4022 "2026-06-27T15:52:06Z")
I believe I have correctly re-written an Abaqus UEL into a format usable for CalculiX (User Element Troubleshooting), and now I am trying to verify it works as intended in comparison to analytical solutions. Unfortunatel… --- ## [Modelling a bearing using a bearing stiffness matrix](https://calculix.discourse.group/t/modelling-a-bearing-using-a-bearing-stiffness-matrix/3842)
**Author:** [@Jan](https://calculix.discourse.group/u/Jan)\ **Replies:** 11\ **Last updated:** [May 4, 2026, 7:11am UTC](https://calculix.discourse.group/t/modelling-a-bearing-using-a-bearing-stiffness-matrix/3842 "2026-05-04T07:11:37Z")
Hey everyone! I recently started using CalculiX and am trying to model a shaft with two bearings. To do this, I want to define a bearing stiffness matrix as supports. I am using PrePoMax as a pre-processor and have tri… --- ## [GAPUNI elements](https://calculix.discourse.group/t/gapuni-elements/3926)
**Author:** [@Juseche](https://calculix.discourse.group/u/Juseche)\ **Replies:** 2\ **Last updated:** [April 25, 2026, 3:17pm UTC](https://calculix.discourse.group/t/gapuni-elements/3926 "2026-04-25T15:17:31Z")
Hi, I’m trying to model a pipe under movement. The pipe is modeled using isotropic hardening plasticity, considering large displacements and deformations (S3 elements are used). Displacement boundary conditions are appl… --- ## [Calculate thermal expansion from a temperature field](https://calculix.discourse.group/t/calculate-thermal-expansion-from-a-temperature-field/3909)
**Author:** [@Nobody-86](https://calculix.discourse.group/u/Nobody-86)\ **Replies:** 6\ **Last updated:** [April 20, 2026, 5:53pm UTC](https://calculix.discourse.group/t/calculate-thermal-expansion-from-a-temperature-field/3909 "2026-04-20T17:53:22Z")
Hi, I’m currently trying my hand at a thermal analysis, but unfortunately it’s not going as well as I’d expected. For the initial setup: I have a model made up of C3D10 elements. A few nodes are fixed to prevent the mo… --- ## [Model stops calculating when multiple materials are defined](https://calculix.discourse.group/t/model-stops-calculating-when-multiple-materials-are-defined/3878)
**Author:** [@Nobody-86](https://calculix.discourse.group/u/Nobody-86)\ **Replies:** 17\ **Last updated:** [April 16, 2026, 8:15pm UTC](https://calculix.discourse.group/t/model-stops-calculating-when-multiple-materials-are-defined/3878 "2026-04-16T20:15:43Z")
I have a model here that, in my opinion, behaves a bit strangely. To keep things simple, my model is currently just a rectangular block, meshed with C3D10 tetrahedral elements. There is a fixed constraint on both long si… --- ## [How to create assemblies from individual parts](https://calculix.discourse.group/t/how-to-create-assemblies-from-individual-parts/3860)
**Author:** [@Nobody-86](https://calculix.discourse.group/u/Nobody-86)\ **Replies:** 7\ **Last updated:** [April 9, 2026, 12:04am UTC](https://calculix.discourse.group/t/how-to-create-assemblies-from-individual-parts/3860 "2026-04-09T00:04:27Z")
I am facing the following issue: I have an INP file in which a component - including the nodes for boundary conditions - is defined using \*NODE, \*ELEMENT, and \*NSET. I now want to combine several of these components into… --- ## [Modeling material failure with FEM](https://calculix.discourse.group/t/modeling-material-failure-with-fem/3849)
**Author:** [@CharlieM](https://calculix.discourse.group/u/CharlieM)\ **Replies:** 19\ **Last updated:** [April 8, 2026, 3:07am UTC](https://calculix.discourse.group/t/modeling-material-failure-with-fem/3849 "2026-04-08T03:07:01Z")
Hello, Are there any example or test inputs that model the failure of a material under load? I was trying to model a 1 mm cube of acrylic glue between two steel bars under tension. The stress in the cube of glue was 1 … --- ## [Visualizing the model / Errors in node definition](https://calculix.discourse.group/t/visualizing-the-model-errors-in-node-definition/3852)
**Author:** [@Nobody-86](https://calculix.discourse.group/u/Nobody-86)\ **Replies:** 8\ **Last updated:** [April 5, 2026, 9:39am UTC](https://calculix.discourse.group/t/visualizing-the-model-errors-in-node-definition/3852 "2026-04-05T09:39:08Z")
Hello everybody, I’ve created an input file. I built the mesh - that is, the nodes and element definitions - myself. So there might be some errors in it (most likely node numbering for element definition). Is there a wa… --- ## [Preformance problems due to high iterations](https://calculix.discourse.group/t/preformance-problems-due-to-high-iterations/3843)
**Author:** [@KoalaKerel](https://calculix.discourse.group/u/KoalaKerel)\ **Replies:** 7\ **Last updated:** [March 25, 2026, 12:22pm UTC](https://calculix.discourse.group/t/preformance-problems-due-to-high-iterations/3843 "2026-03-25T12:22:00Z")
Hello everyone! I’m working on an analysis about heat transfer by way of thermal radiation. CalculiX has been a huge help with this. Currently I am attempting to decrease the amount of time it takes for the simulation t… --- ## [Deformation plasticity strain output](https://calculix.discourse.group/t/deformation-plasticity-strain-output/3836)
**Author:** [@shah](https://calculix.discourse.group/u/shah)\ **Replies:** 7\ **Last updated:** [March 24, 2026, 4:47pm UTC](https://calculix.discourse.group/t/deformation-plasticity-strain-output/3836 "2026-03-24T16:47:33Z")
Hi all, I am currently using v2.22 solver. I was trying to calibrate a material constitutive model using the deformation plasticity option in CalculiX. Per the manual section 8.33, the Ramberg-Osgood parameters are def… --- ## [Maximum number of characters in a .inp line](https://calculix.discourse.group/t/maximum-number-of-characters-in-a-inp-line/1623)
**Author:** [@Disla](https://calculix.discourse.group/u/Disla)\ **Replies:** 16\ **Last updated:** [March 23, 2026, 8:22am UTC](https://calculix.discourse.group/t/maximum-number-of-characters-in-a-inp-line/1623 "2026-03-23T08:22:28Z")
HI, Ccx do not respond properly when I request a TRANSFORM CARD written like: \*TRANSFORM,NSET=NFace,TYPE=R -9.42849795070461E-05,0.707071235581443,-0.707142318719276,-0.707071235581443,-9.42849795070461E-05,0 After m… --- ## [CalculiX failed to run with PrepoMax generated inp file](https://calculix.discourse.group/t/calculix-failed-to-run-with-prepomax-generated-inp-file/3796)
**Author:** [@Charles](https://calculix.discourse.group/u/Charles)\ **Replies:** 12\ **Last updated:** [February 26, 2026, 5:27am UTC](https://calculix.discourse.group/t/calculix-failed-to-run-with-prepomax-generated-inp-file/3796 "2026-02-26T05:27:23Z")
I have a power Ubuntu computer. I want to use PrepoMax on my Windows computer to set up a model, generate inp file and run CalculiX 2.23 with the input file on the ubuntu computer with more cores. I installed Pardiso sol… --- ## [CFN and CFS values](https://calculix.discourse.group/t/cfn-and-cfs-values/3772)
**Author:** [@ahmett](https://calculix.discourse.group/u/ahmett)\ **Replies:** 4\ **Last updated:** [February 9, 2026, 10:01am UTC](https://calculix.discourse.group/t/cfn-and-cfs-values/3772 "2026-02-09T10:01:17Z")
Hello everyone, is it possible to obtain CFN and CFS values for the SURFACE to SURFACE contact. I looked at the manual but I could not see any clear statement. Thank you in advance. --- ## [Revolute joint with 3D elements](https://calculix.discourse.group/t/revolute-joint-with-3d-elements/2921)
**Author:** [@Aly](https://calculix.discourse.group/u/Aly)\ **Replies:** 3\ **Last updated:** [December 12, 2025, 1:34am UTC](https://calculix.discourse.group/t/revolute-joint-with-3d-elements/2921 "2025-12-12T01:34:39Z")
Hello all, How can I model a revolute joint between two separate bodies that are meshed with 3D elements? I don’t want a rigid body constraint, I need to see the deformation of the holes. --- ## [Surface definition for coupling](https://calculix.discourse.group/t/surface-definition-for-coupling/2919)
**Author:** [@auto\_engineer](https://calculix.discourse.group/u/auto_engineer)\ **Replies:** 2\ **Last updated:** [December 11, 2025, 5:35am UTC](https://calculix.discourse.group/t/surface-definition-for-coupling/2919 "2025-12-11T05:35:11Z")
Hey everyone, I’m struggling to define a surface in order to use it later on for a \*COUPLING-Card. Here’s the breakdown of my approach: I have pre-defined surfaces from my pre-processor (gmsh): \*ELEMENT, type=CPS6, E… --- ## [CalculiX Contact Surface](https://calculix.discourse.group/t/calculix-contact-surface/2916)
**Author:** [@ahmett](https://calculix.discourse.group/u/ahmett)\ **Replies:** 5\ **Last updated:** [December 2, 2025, 7:27pm UTC](https://calculix.discourse.group/t/calculix-contact-surface/2916 "2025-12-02T19:27:07Z")
Hi everyone, I am having difficulty in creating surfaces in calculix. I have created my geometry and mesh via gmsh. Then, i get the .inp file. While trying to create surfaces, I am constantly getting the error below. \*… --- ## [CalculiX crashes for edited input file](https://calculix.discourse.group/t/calculix-crashes-for-edited-input-file/2886)
**Author:** [@pl96andy](https://calculix.discourse.group/u/pl96andy)\ **Replies:** 1\ **Last updated:** [October 8, 2025, 9:30pm UTC](https://calculix.discourse.group/t/calculix-crashes-for-edited-input-file/2886 "2025-10-08T21:30:12Z")
Hi all Sorry for noob question but i really have no idea what i am doing wrong i am trying to simulate orthotropic material in calculix. Because prepomax (and freecad) lacks support for orthotropic and \*DISTRIBUTING ke… --- ## [Contact results for \*TIE contact?](https://calculix.discourse.group/t/contact-results-for-tie-contact/2879)
**Author:** [@calc4fem](https://calculix.discourse.group/u/calc4fem)\ **Replies:** 1\ **Last updated:** [September 23, 2025, 1:38pm UTC](https://calculix.discourse.group/t/contact-results-for-tie-contact/2879 "2025-09-23T13:38:10Z")
Is it possible to obtain the results, such as shear stress, nornal stress, etc. at the contact surfaces connected with \*tie? --- ## [2d steady state heat transfer](https://calculix.discourse.group/t/2d-steady-state-heat-transfer/2873)
**Author:** [@JulesMazari](https://calculix.discourse.group/u/JulesMazari)\ **Replies:** 5\ **Last updated:** [September 15, 2025, 10:14am UTC](https://calculix.discourse.group/t/2d-steady-state-heat-transfer/2873 "2025-09-15T10:14:35Z")
Hi, I just starting to learn & use CalculiX. The problem I want to solve is a very simple 2d steady state heat transfer problem. From gmsh, I exported the mesh as inp file and I start completing the file to describe th… [Next page](https://calculix.discourse.group/c/model-setup/9.md?page=1)