Craft with created part is spawning 1 km above the launch pad or exploding

[chris-kerbal]

Hi there,

so first things first, I am not a modder, but putting this here on behalf of @benjee10. He might be too shy to ask ;-)
The issue seems to be tricky and he does not have the time to try and try.
If you feel this is wrong, tell me and I will close the thread.

Within his habtech2 mod there is this complex duo solar array. For some unknown reason a vehicle including this part will either combust on the launchpad or spawn 1km above the pad, then fall down. This happens in 1.9.x and 1.10.x.

Has anyone of the part modders experienced similar issues and could give a hint what to look for?

So far I am using the dev version from github: https://github.com/benjee10/HabTech2
@Gordon Dryadded some of benjees latest work into a test version: https://github.com/Gordon-Dry/HabTech2/tree/merge-for-playtest

Kind Regards
  Chris

[DeadJohn]

I don't know how to fix it, but I do have a workaround. When your craft spawns in the air, open Hyperedit and use the "land here" button to get safely back onto the launch pad or runway, then do a normal takeoff.

[chris-kerbal]

6 hours ago, DeadJohn said:

I don't know how to fix it, but I do have a workaround. When your craft spawns in the air, open Hyperedit and use the "land here" button to get safely back onto the launch pad or runway, then do a normal takeoff.

So you encountered this as well? With the same mod or another one?

[DeadJohn]

6 hours ago, chris-kerbal said:

So you encountered this as well? With the same mod or another one?

Yes, I've encountered it, but different mods. (I don't think I've ever tried HabTech2 - it's on my list of things to try I just haven't gotten around to it.)

One or more OPT parts used to spawn in the air. I think it was the "Humpback" rear cargo ramp. That's an older part and I learned to use the newer "KH" ramp instead.

Edited October 23, 2020 by DeadJohn

[chris-kerbal]

16 minutes ago, DeadJohn said:

Yes, I've encountered it, but different mods. (I don't think I've ever tried HabTech2 - it's on my list of things to try I just haven't gotten around to it.)

One or more OPT parts used to spawn in the air. I think it was the "Humpback" rear cargo ramp. That's an older part and I learned to use the newer "KH" ramp instead.

Thanks a lot, that is good to know! Sadly @K.Yeon and @stali79 seem not to have been active in recent times. They might have had a tip on what to look for.

Edited October 23, 2020 by chris-kerbal
typo

[chris-kerbal]

I figured that @JadeOfMaar picked up OPT development and checked if he/the mod is still plagued by this issue. Here is his answer:

Quote

From what I remember, the bug is caused by bad practice with (usually animated) meshes. I recently made a part that doesn't animate and it had the bug. I can't get at all why that would happen. What I assume is that the origin of an animated mesh is far from the center of its geometry, so when KSP calculates the bounding box of the part, it somehow ends up underground and KSP spawns the part in the air to somehow cover for that. The WorldStabilizer mod (linked in this thread's OP) suppresses the bug. I don't have it in me to deal with OPT's parts (mainly the issue of re-unwrapping and re-atlasing these parts if/when needed) so I can't fix them myself.

So apparently it is still around. Will also check if I can find out what WorldStabilizer does, that this is not happening anymore.

[chris-kerbal]

So within the World Stabalizer Thread @Stone Blue mentioned that he worked on this bug. Here is what he said:

Quote

When I was poking the OPT models, and when I fixed the K-35 engine in QuizTech, I found that it seemed to be the location of the origin of the animated colliders/gameobjects, combined with the way KSP calculates vessel/part bounds. As Whale_2 stated, WS calculates differently than stock KSP.
Unfortunately, at least part of the reason they dont get fixed, and why WorldStabilizer is needed, is that its up to each mods' dev to edit/update the models in their mod, and do a new release. I have most of the OPT parts fixed, but there are other issues right now preventing me from merging the fixes into an update.

I asked if he would be willing to elaborate a bit more on the fixes he did, maybe he can give some valuable input and hints for other modders, but can understand, if he does not have time to give a howto.