Mod that changes the mass of pods depending on kerbal occupancy.

[kahlzun]

Hi guys!

I am interested if anyone has developed, or is interested in developing, a mod that automatically adjusts the mass of the command pods based on the number of kerbals occupying them. (Possibly also the number of 'sample survey' datas stored within it also?)

As it currently stands, the EAS-1 chair is the only part which changes mass, perhaps the coding for that effect could be "Module Manager"ed onto the other pods?

Thanks for consideration,

Sam

Edit:

*Aqua* has kindly coded a plugin based on my request. Thread is here.

Edited February 7, 2015 by kahlzun

[tntristan12]

This... is actually a pretty awesome idea. I wish it were implemented in the stock game, since astronaut weight is a big consideration in real life as well.

[RainDreamer]

Can't just module manager the seat to pods. They use totally different modules.

[kahlzun]

I meant whatever part of the module which triggers the change of weight.

[RainDreamer]

I meant whatever part of the module which triggers the change of weight.

They don't even use the same module to cut/paste that part in.

[kahlzun]

Sorry, im not too good with the internals of KSP.

[FreeThinker]

Technically, the easy way to implement this would be to add a weight resource to any part that can contain Kerbals, and fill it wen a kerbal enters the Part.

[*Aqua*]

I'm currently working on that. But I can't tell you when it'll be released.

There are some things which make me scrach my head (example: Kerbals going on EVA have an initial mass of 3.13 tons - why? I don't know.)

Edited February 2, 2015 by *Aqua*

[kahlzun]

I'm currently working on that. But I can't tell you when it'll be released.

There are some things which make me scrach my head (example: Kerbals going on EVA have an initial mass of 3.13 tons - why? I don't know.)

I'm just happy someone's working on it.

[*Aqua*]

First image: All capsules don't have a crew. CoM in neutral position.

Second image: Capsule has 3 crews (3 x 93.75 kg). CoM moves a bit to the front.

Third image: All capsules are fully manned (3 x 93.75 kg in the front + 3 x 4 x 93.75 kg in the back = 1406.25 kg!). CoM moves back.

I guess some plane engineers are going to be angry with me. ^^

Edited February 2, 2015 by *Aqua*

[rabidninjawombat]

I guess some plane engineers are going to be angry with me. ^^

http://i.imgur.com/Wcyce7N.gif

First image: All capsules don't have a crew. CoM in neutral position.

Second image: Capsule has 3 crews (3 x 93.75 kg). CoM moves a bit to the front.

Third image: All capsules are fully manned (3 x 93.75 kg in the front + 3 x 4 x 93.75 kg in the back = 1406.25 kg!). CoM moves back.

Nice work! good for added realism. Though 93kg seems a bit heavy for a kerbal

[*Aqua*]

A external command seat automatically changes it's part mass by 93.75 kg when a Kerbal boards or leaves it. That's where the number comes from. (I remember there was a discussion about that. People concluded that a Kerbal itself weights about 30 kg. The space suit is the heavy thing.)

You can tweak the Kerbal's mass in a config file if you think it's too much or not enough. I added that to allow modding (had RSS in mind where everything can have a different scale).

I'm almost finished. I still have to test a complete mission with several parts, in the editor, launching and recovering, EVAing and boarding, saving and loading, etc. When nothing goes wrong I'll release this small mod tonight or tomorrow.

[Whirligig Girl]

I guess some plane engineers are going to be angry with me. ^^

http://i.imgur.com/Wcyce7N.gif

First image: All capsules don't have a crew. CoM in neutral position.

Second image: Capsule has 3 crews (3 x 93.75 kg). CoM moves a bit to the front.

Third image: All capsules are fully manned (3 x 93.75 kg in the front + 3 x 4 x 93.75 kg in the back = 1406.25 kg!). CoM moves back.

It looks like you just made crew a resource. Does the mass actually change with Kerbal count?

[*Aqua*]

It's not a resource. I add a new KerbalMassModule to each part which can hold a crew. It changes the part's mass depending on how many Kerbals are in that part. In flight it queries the part's population to work. Ok... in a way it feels like a ressource.

Unfortunately Squad hasn't exposed a public API for the crew assignment in the editor. That's why I added a slider in the context menu to allow a quick and easy way to preview CoM changes. I just needed to do that. For example a MK3 passenger module can hold up to 16 Kerbals, so the difference between fully manned and and empty is 16 * 93.75 kg = 1.5 tons. If you can't preview that difference in the editor people will be bugged.

[kahlzun]

Are you adding the kerbal mass to the initial part, or are you assuming the part as stock comes occupied, and reducing the weight for empties?

[*Aqua*]

There's a switch in the config file to choose one of both behaviors. By default it assumes the initial part mass is without Kerbals.

Currently I'm still trying to figure out how to not save the new module to a save file. The reason for that is to guarantee flawless behavior if the user removed the mod. It already works on the persistence file but not on the VAB save file.

Edit:

I'm sorry, you have to wait a bit more. There is a major problem with saving and loading. The changed mass gets written to the save file. The next time the game loads that save my mod adds more mass to it. So on every saving and loading the part mass increases. My attempts to prevent that didn't work so far.

If this keeps on I'll have to include ModuleManager and rewrite a lot of code. That's a thing I still hope to avoid, even when it has some advantages.

About the switch I mentioned in this post: I'm not sure if it's a good idea to treat the default mass as the total mass including Kerbals. There are some parts like the external command seat which weight less than a Kerbal (50 kg <-> 93,75 kg). Because of the special behavior of parts like the seat (it auto-adds/auto-substracts Kerbal mass on boarding or EVAing) I added blacklist options in the cfg for parts and parts with specific modules. My mod will then ignore them.

I can also add an option to treat these parts in a special way: The mod could reverse what ever that part does with its mass and then apply my mass changes (useful when you change the Kerbal mass in the cfg). Do you want that funtionality?

Edited February 4, 2015 by *Aqua*

[kahlzun]

That would make sense, it would allow changes to Kerbal mass to work as expected.

Though it probably isn't terribly important overall, if its going to be a lot of work, you could always release it 'as is' and have that as a later 'stretch goal'..

Edited February 6, 2015 by kahlzun

[RainDreamer]

I guess now we are also able to use kerbals as counter balance weight.

"Kerbals, today you are tasked with an important duty, one that may means success or failure of the entire mission. You must sit here, strap on your seat belt and...remains like that for the rest of the flight. No wiggling in your seat, no taking your seat belt off, and most importantly, no going to bathroom. May the stars bless your souls."

[KerBlam]

Maybe kerbals weigh that much because they're so dense.

[Superfluous J]

I love this community.

"Hey this would be neat."

"I think I can do that."

"Sweet how long do you think it would take?"

"I've got a prototype working right now..."

[sarbian]

FYI the seat does not add anything. The mass comes from the kerbal itself, who is attached to the seat.

[kahlzun]

Well, yes, but no other part has that effect, which is what this is intending to fix.

[sarbian]

I am not saying otherwise. It's just that there is not code in the seat module to deal with the mass.

Adding the mass with a part module leads to added complexity since other module might also try to change the mass.

[*Aqua*]

FYI the seat does not add anything. The mass comes from the kerbal itself, who is attached to the seat.

That means I don't have to change anything of the seats behavior - as long as there isn't a surprise in the the code. I didn't test that out yet. Thank you for your information!

Adding the mass with a part module leads to added complexity since other module might also try to change the mass.

The other modules can change the part's mass as they like. That's no problem. I'm only adding or substracting mass on EVAing, boarding and transfering. I do not reset the part's mass to a default value or something like that so other module's changes still have their effect applied.

That's reason why I didn't released yet. I just want to make sure that I don't blow up the game.

Edited February 6, 2015 by *Aqua*

[*Aqua*]

I found a surprise in the code. The mass of an EVAed Kerbal is calculated by the KerbalEVA part module. It has an initial mass ('initialMass') of 3.125 tons. That get's multiplied by a factor ('massMultiplier') of 0.03 which results in a final mass of 93.75 kg.

I don't know why Squad did it but that also influences the jet pack. Setting the initialMass to 0.05 and the multiplier to 1 resulted in no more visible RCS exhaust. I didn't test it but I assume the thrust changed also.

Edit: Further test showed it doesn't seam to influence the jet pack. It was another thing I did.

Still I don't know why they came up with this kind of mass calculation.

Edited February 6, 2015 by *Aqua*