CalculiX (official versions are on www.calculix.de, the official GitHub repository is at https://github.com/Dhondtguido/CalculiX).

Topic	Replies	Views	Activity
CalculiX User Meeting 2026 Official announcements Dear CalculiX users, We are pleased to announce the first CalculiX User Meeting, hosted by MTU Aero Engines in Munich. The meeting is aimed at professional CalculiX users and has the following objectives: Learning ab…	5	965	October 19, 2026
Welcome to Discourse Uncategorized	0	3613	July 28, 2020
Engineering suite CAD, Calculix, OpenRadioss (OpenCourant) Tool interfaces	4	33	October 22, 2026
Segmentation fault with ccx_2.19 dynamic modal analysis Uncategorized	13	1235	October 22, 2026
*RIGID BODY with collinear nodes: the manual says "an error will occur", but ccx gives no error or warning, exits 0 and returns wrong displacements Analysis issues	2	41	October 22, 2026
*ELASTIC with an unlisted TYPE (TRACTION, LAMINA, a misspelt ENGINEERING CONSTANT) is read as ISO without a message, or stops with a misleading Poisson error Analysis issues	2	29	October 22, 2026
*BUCKLE does not check its result: with a singular stiffness matrix it prints factors near the shift 1.0 that are not eigenvalues (exit 0, no message) Analysis issues	2	32	October 22, 2026
HYPERELASTIC, OGDEN / HYPERFOAM at 1e-5 to 1e-4 strain: the stretches lose most digits, so OGDEN alpha = 2 is 2.4 % off NEO HOOKE and small increments fail Analysis issues	2	29	October 22, 2026
HYPERELASTIC, OGDEN and HYPERFOAM with alpha ≠ 2: near the unstressed state stiffness and stress use shear modulus 2·mu/alpha, not mu (wrong frequencies) Analysis issues	2	37	October 22, 2026
OFFSET shells and beams with a temperature gradient get wrong expanded-node temperatures: wrong thermal expansion, and beams bend (1 + 2·OFFSET) times as much Analysis issues	2	30	October 22, 2026
CalculiX and LIS solver Code development	8	209	October 22, 2026
*TEMPERATURE, OP=NEW resets shell and beam temperatures to the initial values but keeps the last gradient (the shell stays bent, exit 0) Analysis issues	1	32	October 22, 2026
Initial shell/beam temperature gradient, no *TEMPERATURE in step 1: outer expanded nodes get the "undefined" marker 1.2357 -/+ g·t/2 (spurious thermal strain) Analysis issues	2	31	October 22, 2026
S4 and B31 ignore shell and beam temperature gradients (the expanded C3D8I takes the element's mean temperature): no thermal bending, no message Analysis issues	2	25	October 22, 2026
FILE NAME WITH SOME SPACE *ERROR in u_calloc Analysis issues	0	14	October 22, 2026
Cyclic symmetry ngraph=2 corrupted results file for restart frequency analysis Analysis issues	3	103	October 22, 2026
FREQUENCY step leaves the last eigenmode's strain energy in the internal energy (ELSE), and a following DYNAMIC or NLGEOM *STATIC step adds to it Analysis issues	2	40	October 22, 2026
RF leaves out the MPC force at supports that belong to an element: EQUATION supports, and RIGID BODY ref nodes with a spring or *TRANSFORM, print 0 (exit 0) Analysis issues	2	40	October 22, 2026
Shell moment near the normal: the drilling check in gen3dforc.f never triggers (dot.gt.999d0), so the moment is amplified, not removed; a second moment is dropped Analysis issues	2	35	October 22, 2026
KINEMATIC coupling (or a MEANROT MPC) in a *DYNAMIC step: no equation system is set up, every free DOF keeps its initial value (exit 0, no message) Analysis issues	2	31	October 22, 2026
Implicit *DYNAMIC step after a strained step: internal energy (ELSE) and the step's "initial energy" start at twice the value, with nothing moving Analysis issues	2	42	October 22, 2026
Moment on a beam or shell node in a step after *BUCKLE: a second mean-rotation MPC is made, and cascade loops forever or the moment is lost or changed (exit 0) Analysis issues	2	42	October 22, 2026
Axisymmetric elements: radial RF picks up the hoop force of the 2° segment, so one CAX4 shows 0.38 of the reaction and free, unloaded nodes show RF Analysis issues	2	34	October 22, 2026
Material without DENSITY, SPECIFIC HEAT or *CONDUCTIVITY gets only a warning; its elements take the previous element's value, so results depend on numbering Analysis issues	2	34	October 22, 2026
*DLOAD BX/BY/BZ on shell elements becomes a pressure along the normal: wrong direction, 1/t too large, sign set by the node order (exit 0, no message) Analysis issues	2	38	October 22, 2026
FREQUENCY / BUCKLE after a nonlinear step: an EQUATION that a RIGID BODY or knot MPC depends on is not decascaded again, wrong eigenvalues (exit 0, no message) Analysis issues	2	38	October 22, 2026
Installation of CCX_2.23 fun Getting started	19	539	October 21, 2026
Abq2ccx input converter (Abaqus to CalculiX) Tool interfaces	19	519	October 21, 2026
*ELEMENT with an unlisted TYPE starting with "D" (e.g. DASHPOT2) is read as a 3-node network element: two DASHPOT2 elements run with exit 0 and no damping Analysis issues	0	20	October 21, 2026
Supported ARPACK-NG or unsupported old ARPACK? What is better? Code development	0	27	October 21, 2026

CalculiX User Meeting 2026

Dear CalculiX users, We are pleased to announce the first CalculiX User Meeting, hosted by MTU Aero Engines in Munich. The meeting is aimed at professional CalculiX users and has the following objectives: Learning ab…