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ferram4 / Ferram-Aerospace-Research

Aerodynamics model for Kerbal Space Program
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Reference Area changes with scene load #120

Open Gaiiden opened 8 years ago

Gaiiden commented 8 years ago

I noticed this on Hayes in 1.0.4 but it has also been confirmed for the latest release on 1.0.5.

Steps to reproduce:

  1. Load a craft into the flight scene, note Ref Area value
  2. Return to Space Center
  3. Load the craft again. Note change in Rf Area value

The value is also different every time I load the game and go straight to the craft

Issue on forums

ferram4 commented 8 years ago

There appear to be two possible causes for this.

For most vessels, the primary cause is just numerical errors caused by slight changes in vessel orientation. Most of these are happening a bit above the level of precision that can be expected for singles and with most of the mesh data and transform matrices in singles I doubt that these can be improved.

For vessels with tracking solar panels or radiators it appears to change based on panel orientation, which means that the issue can be fixed for that case, though it might take some time to do it sanely.

Gaiiden commented 8 years ago

the vessel I used as an example has tracking panels but I made sure they and any other movable parts were stowed. Precision is probably the cause here. It's not a huge discrepancy but I noticed the variation and just wanted to make sure it wasn't part of any larger issue

Vladokapuh commented 7 years ago

Got similar issue, so i decided to post here instead of new issue. Would be glad to know if its FAR related issue, or some other mod causing it.

My Ref Area reacts different to retracting or extending gear legs. Either: Ref Area changes from ~92 to ~87, but retracting gear has no major impacts on planes flight. https://i.imgur.com/xvaRcsx.png (gear down) https://i.imgur.com/d6xpjFy.png (gear up) Or: Ref Area doesnt react to gear retraction, but once gear retracts, the plane starts pulling far less G's and ALOT less AoA. https://i.imgur.com/hvAwNgn.png (gear down) https://i.imgur.com/C2lNe6d.png (gear up)

Thats a 5% difference, and it very precisely jumps between those values, dont think this is precision issue. Difference in how plane flies is HUGE. This is using latest build of FAR, latest build of KSP. Mods this plane uses are: Airplane Plus, BDArmory, and also KJR.

If you need any more information, tell me what you need!

(i cannot seem to upload a log in a ZIP file, so i uploaded it as DOCX) KSP.docx

This one is ZIP with craft file just renamed to docx so it uploads, rename to .zip if you need this. plane.docx