m4v

[1.2] RCS Build Aid v0.9.1

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52 minutes ago, linuxgurugamer said:

Ok.  Try this, please:

https://www.dropbox.com/s/d1u3jstepbd8gbd/RCSBuildAidSkinFixBeta3.zip?dl=0

Oh, and before someone complains, my github repo has the latest changes

Just tested this in my many mod game and looks good. The usual steps I was using to create a display glitch are no longer a problem.

Spoiler

Steps that used to cause a glitch:

  • put craft in eccentric orbit around Kerbin
  • set moon as target
  • open manoeuvre planner window in MechJeb
  • select "Hohmann transfer to target" from dropdown and click "Create node" button
  • large block of warning text is displayed that should wrap onto several lines but wasn't in bugged version

 

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Great, will get a new release file out.

Thanks  for testing

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Many thanks, LGG. 

That seems to have done the job. 

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Hey there

Can someone help me understand how this works?

screenshot8.png

I have one RCS thruster only, with RCS-BA set to display attitude. I don't understand where the straight red arrow comes from, or how to get rid of it. I know the green arrow represents the translation movement, and the red circle represents how fast the rotation will occur. The straight red arrow represents the torque force on the craft, but I don't know where it comes from or how to remove it. The only way I can seem to remove it completely is to set put the thruster at the centre of mass, which then removes the rotation as well.

And then this image

screenshot9.png

I have two equal thrusters, both firing in the same direction, and yet there is a net torque force in one direction that I don't understand where it comes from.

Thanks

Edited by strudo76
Additional picture

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8 hours ago, strudo76 said:

Hey there

Can someone help me understand how this works?

<snip>

I'll give it a try. TL:DR is that the red arrow is your torque vector; the way you get it go away entirely is either by putting your thruster on your center of mass OR by putting an equal amount of counter-force at a distance exactly as far away from the center of mass as your initial thruster. 

There are three components to torque - the amount of force applied (which depends on the output of your thrusters), the length of the lever arm (i.e. how far the thruster is from the center of mass, which is going to be your fulcrum), and the angle between them. In this case, your force vector is going to be at a right angle to the lever arm - sine of ninety degrees is 1, so that factors out of consideration. So, the magnitude of your torque in a given axis is going to equal the thrust times the distance to the center of mass. The direction of the torque vector can be determined by using the right hand grip rule: if the fingers of the right hand are curled from the direction of the lever arm to the direction of the force, then the thumb points in the direction of the torque. What RCS Build aid is doing when it's telling you the total torque on a single axis is that it's calculating the torques for all thrusters that will affect that axis - the amount of force they provide, how far away they are from the selected CoM, and what angle they are to the axis. It then adds those up and gives you the result. 

If you're really wanting to use RCS thrusters for rotation with a craft like the one you've pictured, I'd start by putting a series of thrusters at the top - up by the parachute. These won't be at a ninety degree angle to the lever arm, and so the net torque they'd produce will be less than those you could put at the same distance from the CoM on the bottom. Myself, I use RCS thrusters for docking, which is a procedure where you want as little torque produced when you fire a thruster as you can possibly manage (so therefore I put them around the center of mass)
 

https://en.wikipedia.org/wiki/Torque - mandatory wikipedia link on the topic of torque.

I don't think I've really explained this particularly well; hopefully at least some of this is helpful.

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Few pages back and couple of months ago, I tried to explain it to other user:

 

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21 hours ago, capi3101 said:

I'll give it a try. TL:DR is that the red arrow is your torque vector; the way you get it go away entirely is either by putting your thruster on your center of mass OR by putting an equal amount of counter-force at a distance exactly as far away from the center of mass as your initial thruster. 

...

 

I don't think I've really explained this particularly well; hopefully at least some of this is helpful.

 

19 hours ago, kcs123 said:

Few pages back and couple of months ago, I tried to explain it to other user:

 

Both very helpful posts, thank you. I guess my only remaining question is will the craft translate in the direction of the torque vector while I'm rotating?

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4 hours ago, strudo76 said:

Both very helpful posts, thank you. I guess my only remaining question is will the craft translate in the direction of the torque vector while I'm rotating?

Game will always try to translate craft, meaning, it will turn on those RCS ports that have at least some thrust(force) that will push craft (translate) it in desired direction. While doing this, depending on position of RCS ports that try to translate craft in desired direction you will get also unwanted rotation.

When you get unwanted rotation, game will again try to engage RCS ports that should provide oposite force that cancel rotation. Often, those ports provide oposite force from direction of desired translation, therefore also waste of fuel.

Keeping that in mind, what you want in craft design process, to minimize rotation, idealy it should be zero, when you try to translate craft in any of desired direction. That is where this mod kicks in, giving you visual feedback, how much of rotation you get for any of translation direction. By placing RCS on symetrical distance from COM, or changing thrust maximum for each RCS port, you can achieve zero rotation or near zero rotation for all translation direction.

I'm saying near zero rotation, because you have design craft very carefuly in a way that COM does not shift at all when you drain fuel and other resources. Also, having zero rotation for any given translation, does not mean that you would not rotate craft with RCS at all. It yust mean you didn't waste resources on rotation that you does not want.

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5 hours ago, strudo76 said:

Both very helpful posts, thank you. I guess my only remaining question is will the craft translate in the direction of the torque vector while I'm rotating?

It will not translate in the direction of the torque vector.  The torque vector could just as easily point in the opposite direction, the only reason it doesn't is mathematical convention.

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For anyone having problems with identifying the direction the ship will turn when looking at the torque vector, use the "right hand rule" (or right thumb rule). Make a fist with right hand with thumb popping out, now, if you put the fist in such a way that the thumb is pointing in the same direction as the torque vector (red arrow), the 'curl' of the other 4 fingers represents the direction in which the ship rotates. Check this more info and images:Right Hand Rule

Great mod, this should be stock IMHO. It becomes frustratingly hard trying to balance RCS and engine torque without this. Thanks @m4v for the mod and @linuxgurugamer for the fixes!

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I can't use RCS Build Aid right now i havent play ksp for a while downloaded it recently and take x science engineer redux and rcs build aid but i couldn't download it from ckan i download it from here first 1.2 version icon appeared on screen but when i click it nothing happend than i download 9.1.2 version at the last page but know cant even see icon in hangar

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On 19.07.2017 at 7:08 PM, MaverickSawyer said:

@linuxgurugamer is, thankfully, running a continuation project that has released a 1.3 compatible version.

is it out? 

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8 hours ago, Kobymaru said:

I wonder if it's possible to add a CKAN source for all of your stuff. Would be wonderful if we could just plop that into CKAN and update to your unofficial rebuilds.

AFAIK, CKAN doesn't do betas, which is how this unofficial update is characterized on GitHub.

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2 hours ago, Brigadier said:

AFAIK, CKAN doesn't do betas, which is how this unofficial update is characterized on GitHub.

Actually you can setup CKAN to install a DEV version. I do this with mechjeb. You'd have to add a special dev repo for your stuff to the CKAN github though.

Then in CKAN you add a line to your setting to add a metadata repo. Currently SCANsat, Trajectories, Mechjeb, and RemoteTech have this option.

 

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It's the new repo in CKAN which I'm avoiding, too much chance of confusion

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3 minutes ago, linuxgurugamer said:

It's the new repo in CKAN which I'm avoiding, too much chance of confusion

Well it shouldn't be on by default, but it would be very helpful for those who know what they are doing.

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