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Bug #26939

Trajectory changing while rotating ship

Added by Anonymous over 3 years ago. Updated over 2 years ago.

Status:
Resolved
Severity:
Low
Assignee:
-
Category:
Physics
Target version:
1.11.1
Start date:
12/27/2020
% Done:

100%

Version:
1.11.0
Platform:
Windows
Expansion:
Core Game
Language:
English (US)
Mod Related:
No
Votes:
Arrow u r green
Arrow d r red

Description

Craft with small parts (<30kg mass but no so small that their mass is centered on the ship) act as if they accelerate when rotating.

In the attached savefile, start the small probe rotating:
+ its intercept with Duna changes by distances larger than the orbital radius of Ike,
+ the small triangle above the altimeter is orange, indicating the craft is under acceleration so no quick-saving.

Reported at https://forum.kerbalspaceprogram.com/index.php?/topic/198991-111-trajectory-changing-while-rotating-ship/#comment-3899539

Related to #26898
Workaround from that issue works here as well (beware possible side effects regarding dropping parts during EVA constructions, speculated at that thread) editing 'hPhysics.cfg' to change the line with 'partRBMassMin' to
partRBMassMin = 0.005

Some mods have lighter parts that can be independent rigid bodies, specifically the GP-004 grip pad from Breaking Ground used in some examples posted above. So for games including these parts, a lower minimum

  partRBMassMin = 0.002

probe.jpg (35.2 KB) probe.jpg affected craft, Duna intercept on that craft's trajectory Anonymous, 12/27/2020 06:48 PM
imbalanced.sfs (164 KB) imbalanced.sfs savefile Anonymous, 12/27/2020 06:49 PM
55500

History

#1 Updated by VoidSquid over 3 years ago

Shouldn't this be listed as for KSP 1.11.0 instead of 1.10.1?

#2 Updated by Anonymous over 3 years ago

  • Description updated (diff)
  • Version changed from 1.10.1 to 1.11.0

#5 Updated by Anonymous over 3 years ago

  • Description updated (diff)

#6 Updated by victorr about 3 years ago

  • Status changed from New to Ready to Test
  • Target version set to 1.11.1
  • % Done changed from 0 to 80

We've made some changes in the latest version of the game and would like some feedback on this issue. Thanks.

#7 Updated by Anonymous about 3 years ago

The change to partRBMassMin = 0.002 solves the problem for the examples in the original report,
but as noted at the related bug #26898 there are a few parts in the DLCs lighter than 2kg that have physicsSignificance = 1.
Rebuilding the example with, for example, a "Tiny Nosecone" restores the symptom.

#8 Updated by Technicalfool over 2 years ago

  • Status changed from Ready to Test to Resolved
  • % Done changed from 80 to 100

Setting this issue to resolved. If any more related bugs have creeped in, please report them as usual.

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