# Beam to truss connection for cable supported structures **URL:** \ **Category:** Analysis issues\ **Created:** [December 15, 2025, 2:44pm UTC](https://calculix.discourse.group/t/beam-to-truss-connection-for-cable-supported-structures/2922 "2025-12-15T14:44:32Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![WP\_316](https://avatars.discourse-cdn.com/v4/letter/w/a587f6/32.png) [@WP\_316](https://calculix.discourse.group/u/WP_316)\ **Post date:** [December 15, 2025, 2:44pm UTC](https://calculix.discourse.group/t/beam-to-truss-connection-for-cable-supported-structures/2922/1 "2025-12-15T14:44:32Z")
Hello, I am trying to model a cable-supported beam structure. I need a way of connecting T3D2 elements to B32s. Shared nodes do no constrain the truss in the Z-direction, and including Rigid Body causes a non-convergence. I can’t use SPRINGAs, as I need temperature dependence for preloading. Thanks ---
**Author:** ![frank-b](https://avatars.discourse-cdn.com/v4/letter/f/6de8d8/32.png) [@frank-b](https://calculix.discourse.group/u/frank-b)\ **Post date:** [December 15, 2025, 8:03pm UTC](https://calculix.discourse.group/t/beam-to-truss-connection-for-cable-supported-structures/2922/2 "2025-12-15T20:03:02Z")
Shooting off the hip here but is it possible to just add a couple of Z restraints on the truss? Don’t know your model but initially there may not be much load perpendicular to the truss? ---
**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:** [December 16, 2025, 11:41am UTC](https://calculix.discourse.group/t/beam-to-truss-connection-for-cable-supported-structures/2922/3 "2025-12-16T11:41:14Z")
Check this thread:[Beams and truss don't connect in Z](https://calculix.discourse.group/t/beams-and-truss-dont-connect-in-z/973) ---
**Author:** ![WP\_316](https://avatars.discourse-cdn.com/v4/letter/w/a587f6/32.png) [@WP\_316](https://calculix.discourse.group/u/WP_316)\ **Post date:** [December 16, 2025, 4:36pm UTC](https://calculix.discourse.group/t/beam-to-truss-connection-for-cable-supported-structures/2922/4 "2025-12-16T16:36:01Z")
Thanks! There’s a good 40-50 such connections so was looking for a slightly quicker solution, but will work for now ---
**Author:** ![vicmw](https://avatars.discourse-cdn.com/v4/letter/v/6de8d8/32.png) [@vicmw](https://calculix.discourse.group/u/vicmw)\ **Post date:** [December 16, 2025, 6:35pm UTC](https://calculix.discourse.group/t/beam-to-truss-connection-for-cable-supported-structures/2922/5 "2025-12-16T18:35:53Z")
If you don’t mind rebuilding CCX, the fix is a couple of lines in gen3dnor.f. Move `beam=.false.` from the else clause in line 466 to outside the loop before line 457. Alternatively, you might be able to work around it by renumbering the elements. Put all the beams at higher numbers than the truss elements. ---
**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:** [December 16, 2025, 6:46pm UTC](https://calculix.discourse.group/t/beam-to-truss-connection-for-cable-supported-structures/2922/6 "2025-12-16T18:46:45Z")
> [@vicmw](#): > > If you don’t mind rebuilding CCX, the fix is a couple of lines in gen3dnor.f. Move `beam=.false.` from the else clause in line 466 to outside the loop before line 457. I think that we should ask Guido to change this in his GitHub repo so that [Truss and beam elements disconnected · Issue #14 · Dhondtguido/CalculiX · GitHub](https://github.com/Dhondtguido/CalculiX/issues/14) is finally resolved. ---
**Author:** ![WP\_316](https://avatars.discourse-cdn.com/v4/letter/w/a587f6/32.png) [@WP\_316](https://calculix.discourse.group/u/WP_316)\ **Post date:** [December 16, 2025, 9:19pm UTC](https://calculix.discourse.group/t/beam-to-truss-connection-for-cable-supported-structures/2922/7 "2025-12-16T21:19:22Z")
I think rebuilding CCX (windows) is beyond me, however your hack with the renumbering worked, but the complete other way around. Trusses after beams work perfectly. Getting this sorted in a future build would be amazing (thanks in advance Guido!) ---
**Author:** ![vicmw](https://avatars.discourse-cdn.com/v4/letter/v/6de8d8/32.png) [@vicmw](https://calculix.discourse.group/u/vicmw)\ **Post date:** [December 16, 2025, 10:52pm UTC](https://calculix.discourse.group/t/beam-to-truss-connection-for-cable-supported-structures/2922/8 "2025-12-16T22:52:56Z")
It would be nice but beware there are a lot of other bugs in beam and truss elements, some of them more subtle than this. Be careful to validate your results thoroughly.