Bug #18849

Autostruts can lock the Advanced Grabbing Unit's pivot

Added by peteletroll about 3 years ago. Updated almost 2 years ago.

Not Fixed
Target version:
Start date:
% Done:


Core Game
English (US)
Mod Related:
Arrow u r green
Arrow d r red


In some configuration Autostruts lock the Grabber pivoting capability.
From experimenting with modding, it looks like IJointLockState.IsJointUnlocked() is not called in these cases.

Steps to reproduce:

1. Launch the included craft (Autostrut Bug.craft);
2. Arm the Grabber;
3. Stage: the Grabber will fall and grab the FL-A5 Adapter;
4. Autostrut the Grabber to grandparent part: the Grabber will connect to th lower RC-001S Guidance Unit;
5. Free the Grabber pivot;
6. The Grabber won't be able to pivot!

The same bug appears if the upper Battery Bank is autostrutted to grandparent part (the lower FL5-Adapter the Grabber grabbed).

Autostrut Bug.craft (15.4 KB) Autostrut Bug.craft Test craft to replicate the bug peteletroll, 05/09/2018 04:48 PM


#1 Updated by peteletroll about 3 years ago

This is important for all mods that make parts move (Infernal Robotics and DockRotate for instance).

#2 Updated by peteletroll almost 3 years ago

Probably related to #18356

#3 Updated by [email protected] almost 2 years ago

  • Status changed from New to Confirmed
  • % Done changed from 0 to 10

Confirmed in 1.7.0 by building craft similar to the one attached to the original post.

Most auto-struts that should break when the pivot goes free, do properly break.
Only auto-struts from the grabber itself, and auto-struts from a part attached to the grabber to a grandparent across the pivot joint, fail to disconnect when the pivot is freed.

#4 Updated by [email protected] almost 2 years ago

In version 1.7.1, this is partially fixed. In the second example from the top post, where we autostrut the Battery Bank to grandparent, now freeing the pivot properly breaks that autostrut across the joint, restoring it when we re-lock the pivot.

Autostrutting the grabber itself to something else still prevents its free pivoting.

#5 Updated by meirumeiru almost 2 years ago

not in all modes I guess... grandParent should work, heaviest should not work, root should not work ... but I'm not allowed to know this... tell me if you are interested in the explanation

#6 Updated by chris.fulton almost 2 years ago

  • Status changed from Confirmed to Ready to Test
  • Target version set to 1.7.2
  • % Done changed from 10 to 80

Several Changes and bug fixes have been made, moving this bug to RTT and can you check it in

#7 Updated by [email protected] almost 2 years ago

  • Status changed from Ready to Test to Not Fixed
  • % Done changed from 80 to 50

The behavior is the same as in version 1.7.1 : only auto-strutting the grabber itself prevents the pivoting.

That behavior is and was the same in all auto-strut modes (grandparent, root, or heaviest part) for the example given above, because all those struts bridge the base of the grabber to something on the other side of the pivot.

Also available in: Atom PDF