Engine rotors spinning wrong way?

[Xenro66]

I haven't used this account in quiet some time, nor do I play much KSP anymore... But this has been an ongoing issue for me for ages. Any engine with a rotor, be it stock (Goliath) or modded (in this case Airplane+), the rotors seem to spin backwards. I feel that this isn't major enough to put in any other forum section and may seem trivial, but it's been bugging me for ages. Redownloading the game isn't something I want to do ^{(due to my very slow internet and limited bandwidth)} and I've tried removing all mods, but this minor issue still remains. If anyone has any ideas on what I can try before giving in and reinstalling, it would be greatly appreciated. Here's a gif so you understand what I'm talking about.

 

 

Edit: I just reinstalled the game, no mods, nothing other than stock parts and settings... Rotors still going backwards. This is an issue with the core game. Although minor, I think it should be fixed. No jet engine I've seen IRL pushes air out the front

Edited August 12, 2018 by Xenro66
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[Zeiss Ikon]

It's probably emulating a stroboscopic effect.  Ever seen the spokes in a stagecoach wheel seem to turn backward in an old Western movie?  It's because, between one frame and the next, the spokes most almost to the old position of the next spoke.  Vary the speed of rotation a little, and the fixed frame rate of the movie camera will make the wheels seem to spin forward, normally (at very slow speed), slow down, stop, run backward, slow down again, and furn forward again as the rotation rate gives various almost, exact, and just over integer spoke spaces between frames.

There are also a number of YouTube videos that show helicopters in flight with what appear to be stopped rotors -- again, the rotor speed (which is nearly constant in a properly operating chopper) happens to match up with the frame rate of the video camera (and the very short shutter opening in bright sunlight gives a sharp image even when the rotor is turning at hundreds of m/s at the tips).

[Xenro66]

15 minutes ago, Zeiss Ikon said:

It's probably emulating a stroboscopic effect.  Ever seen the spokes in a stagecoach wheel seem to turn backward in an old Western movie?  It's because, between one frame and the next, the spokes most almost to the old position of the next spoke.  Vary the speed of rotation a little, and the fixed frame rate of the movie camera will make the wheels seem to spin forward, normally (at very slow speed), slow down, stop, run backward, slow down again, and furn forward again as the rotation rate gives various almost, exact, and just over integer spoke spaces between frames.

There are also a number of YouTube videos that show helicopters in flight with what appear to be stopped rotors -- again, the rotor speed (which is nearly constant in a properly operating chopper) happens to match up with the frame rate of the video camera (and the very short shutter opening in bright sunlight gives a sharp image even when the rotor is turning at hundreds of m/s at the tips).

Trust me, it's not the stroboscopic effect. I had just started the engines, spooled them up 1% for a split second then back to 0%. The rotation you see is the actual speed and direction

Edit: Screw it, I'm just going to reinstall the game. Might a few hours or a day, but it's best to get a fresh start and see if this minor issue remains.

Edited August 12, 2018 by Xenro66
added more info

[EpicSpaceTroll139]

That is... weird... to say the least. I have never seen this before...

Wouldn't make sense for it to be stroboscopic effect either because you can see the white spiral doohickey on the spinner is turning how you would expect. Have you tried it with your various mods uninstalled (just cut/paste them out of the gamedata folder)? Maybe one of them is having some bizarre effect on the direction of rotation for all jets?

I'm really at a loss for what would cause that.

Edited August 12, 2018 by EpicSpaceTroll139

[Zeiss Ikon]

Ah, I see now, the spiral on the center spinner is turning the wrong way, too.  Seems to me the jets in my RO install do this, too.  Maybe a sign or trig error in the animation?

[Xenro66]

7 minutes ago, EpicSpaceTroll139 said:

That is... weird... to say the least. I have never seen this before...

Wouldn't make sense for it to be stroboscopic effect either because you can see the white spiral doohickey on the spinner is turning how you would expect. Have you tried it with your various mods uninstalled (just cut/paste them out of the gamedata folder)? Maybe one of them is having some bizarre effect on the direction of rotation for all jets?

I'm really at a loss for what would cause that.

I've tried removing every mod and every config that's not of Squad origin, yet it still persists. Once the game reinstalls, I will check to see if it's still doing this. If not, then it's a mod. If it is, then this is out of my control. Under the assumption that a mod is causing this, I will add them in 1 by one and restart the game each time to pinpoint which one it is. I have around 20 mods, only 2 of which are part mods (legacy parts and Airplane+), neither of which are the cause... We'll just have to see.

1 minute ago, Zeiss Ikon said:

Ah, I see now, the spiral on the center spinner is turning the wrong way, too.  Seems to me the jets in my RO install do this, too.  Maybe a sign or trig error in the animation?

I'm not sure what kind of trigonometry error could cause this, but I won't rule it out as a possibility. For all I know, it could be as simple as a -1 being used in stead of 1 somewhere in the configs.

[Zeiss Ikon]

2 minutes ago, Xenro66 said:

I'm not sure what kind of trigonometry error could cause this, but I won't rule it out as a possibility. For all I know, it could be as simple as a -1 being used in stead of 1 somewhere in the configs.

Some methods of rotating an image on screen use trigonometry to redraw after a small rotation.  KSP probably can't use pre-rendering, because you need to be able to rotate the "camera" to arbitrary angles, but it's most likely also true that they aren't using the Unity physics engine to rotate internal parts of an engine that handles as a single part -- so something, somewhere, is rotating a 3D shape and rendering it at frame rate; given the presence of a math coprocessor (which does trig functions very rapidly by using an immense internal lookup table)  built into all modern CPUs, it might well be a case of using TAN instead of -TAN or something similar.

[Xenro66]

8 minutes ago, Zeiss Ikon said:

Some methods of rotating an image on screen use trigonometry to redraw after a small rotation.  KSP probably can't use pre-rendering, because you need to be able to rotate the "camera" to arbitrary angles, but it's most likely also true that they aren't using the Unity physics engine to rotate internal parts of an engine that handles as a single part -- so something, somewhere, is rotating a 3D shape and rendering it at frame rate; given the presence of a math coprocessor (which does trig functions very rapidly by using an immense internal lookup table)  built into all modern CPUs, it might well be a case of using TAN instead of -TAN or something similar.

I just reinstalled the game, didn't take as long as I thought. Looks like this is an issue with the core game; brand new and fresh install, rotors still going backwards. So you might be right...

[Zeiss Ikon]

1 minute ago, Xenro66 said:

I just reinstalled the game, didn't take as long as I thought. Looks like this is an issue with the core game; brand new and fresh install, rotors still going backwards. So you might be right...

Yep.  If it really, really bugs you, don't use the large turbofan engines... 

[Xenro66]

1 minute ago, Zeiss Ikon said:

Yep.  If it really, really bugs you, don't use the large turbofan engines... 

Honestly, I've been avoiding them since they were added just because of this. I like making massive cargo planes and these are the only engines that look the part and act accordingly. I know that an animation going backwards is a trivial reason not to use these engines, but it's so distracting when you notice it  . Gif just to prove this happens with stock engines too on a fresh install

And yes, even on idle, the rotors are speeding up and slowing down for no apparent reason xD

 

[SpannerMonkey(smce)]

Hi the Goliath engines use  the stock module FXModuleAnimateThrottle as do many other mod engines,  to rotate the turbine elements, this is a unity created animation, so if it isn't the aforementioned stroboscopic effect, then they have simply been animated running  backwards. Reinstalling the game will not fix the issue. All i can suggest is to check the bug reports  see if there's anything related and add to or create new bug report https://bugs.kerbalspaceprogram.com

 

Edit, regardless of what anyone tells you, it'd take a competent mod maker, with the raw assets no more than 20 minutes to fix the problem, finding the asset would  probably take longer than fixing it

Edited August 14, 2018 by SpannerMonkey(smce)

[Vanamonde]

Sounds like a support issue. And so, moved to support.