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Bug #3919

Center of lift appears differently in VAB and SPH

Added by sdelisle about 10 years ago. Updated over 8 years ago.

Status:
Closed
Severity:
Very Low
Assignee:
-
Category:
Gameplay
Target version:
-
Start date:
01/01/2015
% Done:

100%

Version:
0.90
Platform:
Any
Expansion:
Language:
English (US)
Mod Related:
No
Votes:
Arrow u r green
Arrow d r red

Description

I was building a spaceplane, and had to launch it from the VAB because of the part count limit. I noticed the center of lift appeared really wrong in the VAB.

Even though the vector appears weird, the vessel seems to fly normally.

Steps to reproduce:

  1. Build something that looks like a plane in the SPH
  2. Save it
  3. Go in the VAB, and select the saved vessel from the "SPH" list
  4. Note the orientation of the vessel on import, and the position of the CoL marker.
  5. Select the root part to automatically orientate the vessel to the vertical.
  6. Note the new CoL marker position.

Example 1:

In spaceplane hangar:

Vessel as it appears in the spaceplane hangar

In VAB:

Same vessel, loaded in the VAB

Rotated in VAB for horizontal launch:

Same vessel, loaded in the VAB and rotated

Example 2: http://imgur.com/a/Yoqka

SPH.jpg (499 KB) SPH.jpg Vessel as it appears in the spaceplane hangar sdelisle, 01/01/2015 12:19 PM
VAB.jpg (554 KB) VAB.jpg Same vessel, loaded in the VAB sdelisle, 01/01/2015 12:20 PM
VABrotated.jpg (752 KB) VABrotated.jpg Same vessel, loaded in the VAB and rotated sdelisle, 01/01/2015 12:22 PM
Polaris I.craft (81.6 KB) Polaris I.craft saves\default\Ships\SPH\ sdelisle, 01/02/2015 12:28 PM
KSP.log (147 KB) KSP.log sdelisle, 01/02/2015 12:30 PM
CoL test craft.zip (2.06 MB) CoL test craft.zip sdelisle, 01/02/2015 12:46 PM
#3919-polaris-sph.png (1.36 MB) #3919-polaris-sph.png SPH (native) - major axis up - expected Squelch, 01/02/2015 01:40 PM
#3919-polaris-vab.png (1.23 MB) #3919-polaris-vab.png VAB (imported) - major axis forward. CoL offset forward - unexpected Squelch, 01/02/2015 01:41 PM
#3919-test-sph.png (1.6 MB) #3919-test-sph.png SPH (native) - major axis up - expected Squelch, 01/02/2015 01:46 PM
#3919-test-vab.png (1.47 MB) #3919-test-vab.png VAB (imported) - major axis backward. No apparent offset - unexpected Squelch, 01/02/2015 01:47 PM
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History

#1 Updated by Squelch about 10 years ago

  • Status changed from New to Need More Info
  • Severity changed from Normal to Very Low

I have not been able to reproduce this behaviour on a stock game. I built a couple of craft, including an attempt to copy the one in the images, and the CoL marker appears to be rendered correctly in both the SPH and VAB. I am unable to see any discernable difference in the two construction modes apart from the expected direction change.

I notice you are using Kerbal Engineer, ans possibly other mods which may be affecting the CoL marker. Could you please try to replicate in a clean game to rule out all other variables, and then attach the affected craft file and logs?

#2 Updated by sdelisle about 10 years ago

I was able to reproduce it with the same vessel in an unmodded game, in a new sandbox save. Here's the craft and log.

Also included: another simpler craft that has the same issue, with some screenshots.

#3 Updated by Squelch about 10 years ago

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Thanks for the files and stock testing.

I loaded up the craft files, and there does seem to be something odd going on.

The test.craft initially looks to be the same. However the Polaris.craft does appear to be offset longitudinally, but without the lateral offset shown in the initial images, nor the same lateral offset shown in the uploaded test craft images.

The direction of lift (major axes) seems to have reversed for no apparent reason in the test.craft. Both were copied to the SPH folder, and both have been tagged as SPH in the file which would indicate where they were originally built (native), the CoL looks about right except for the direction change when loaded (imported) into the VAB.

Attached are screenshots taken for the two craft as seen on this testers machine (Win7 x64 - KSP x86)

Everything looks as expected with this craft in its native SPH

Imported into the VAB, the CoL is shifted forward

Everything looks ok for the test craft in its native editor

But the CoL major direction makes an unexpected reversal when imported into the VAB. The position appears correct

This needs further testing as I am able to observe that something isn't quite right, I do not get the same results as the original reporter.

#4 Updated by sdelisle about 10 years ago

And did you try bringing the nose of the craft upwards in the VAB? That's when I got the lateral offset.

(Also not sure if that's expected, but just clicking on the cockpit without doing any actual rotation will bring it upwards. Could make sense since we're in the VAB, not sure.)

#5 Updated by Squelch about 10 years ago

  • Description updated (diff)
  • Status changed from Need More Info to Confirmed
  • % Done changed from 0 to 10

sdelisle wrote:

And did you try bringing the nose of the craft upwards in the VAB? That's when I got the lateral offset.

Until you mentioned it, no. I have taken the liberty of adding some extra steps to the reproduction in the original description to make this clear.

I can now confirm that this operation does cause the CoL marker to both reverse direction (to the expected and correct direction) and offsets the marker laterally as seen in the original image.

(Also not sure if that's expected, but just clicking on the cockpit without doing any actual rotation will bring it upwards. Could make sense since we're in the VAB, not sure.)

I believe the origin and vectors are different for the VAB and SPH editor modes, and that behaviour is intended. However, the change in vectors and origin may also be at the heart of this issue.

#6 Updated by TriggerAu over 8 years ago

  • Status changed from Confirmed to Needs Clarification
  • % Done changed from 10 to 0

#7 Updated by TriggerAu over 8 years ago

  • Status changed from Needs Clarification to Closed
  • % Done changed from 0 to 100

Closing this report out for now. If you find it is still occuring in the latest version of KSP please open a new report (and this one can be linked to it.) For best results, the wiki contains really useful info for when creating a report http://bugs.kerbalspaceprogram.com/projects/ksp/wiki.

You can also ask questions about the bug cleanup in the forum here: http://forum.kerbalspaceprogram.com/index.php?/topic/143980-time-to-clean-up-the-bug-tracker/ and tag @TriggerAu to get my attention

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