[1.12.x] SimpleFuelSwitch v1.4.2: Toggle tanks' fuel type in the editor. Simple and lightweight.

[RealKerbal3x]

16 minutes ago, Snark said:

Hey, nice idea! 

-snip-

So, I'll take this under advisement-- shouldn't be too hard to produce a version 1.1.1 that would enable this scenario.  No promises about ETA, since I've got IRL stuff going on too ... but yeah, this is a good idea, I'll make this happen when I can.

Thanks for the idea!

Cool that it could be made possible! If this becomes a thing, I’d better learn how to make MM patches

[theJesuit]

21 hours ago, Snark said:

Thanks to @theJesuit for the feature suggestion! 

You're welcome. Great and awesome job!

As for the above situation with the engine and resource, could you have the resource there but with a maxAmount = 0.  Probably not very tidy.

I assume you can't hide resources in the part.cfg but only when you define the resource.

Peace.

[DStaal]

18 hours ago, 4x4cheesecake said:

Took me some time to find the correct syntax, but I finally managed to make my config working along the default config
Well, to be more precise: I'll undo the changes made by the default config. This will work even if more parts are added and everything should work fine, regardless if the default config is present or got removed.

Installation
You can install my config like every other mod: just extract the content of the .zip file into your KSP install directory. This will merge my config folder into the mod folder.

Configuration
Open the config.cfg, located in 'GameData/SimpleFuelSwitch/configs/Alternative Config/'. This file contains a list of every (stock) fuel tank type and available fuel types. To add a fuel type to a tank, the corresponding entry must be set to 'true'. If you want to remove a fuel type, set the value to 'false' instead. By default, everything is set to 'true'. Do not remove or comment any of these entries!

Affected parts
So far, every tank which contains any stock fuel will be affected, except for:

• Engines
• Air intakes
• Command Pods

What's not possible
You cannot remove the 'default fuel'. For example: A xenon tank will always carry xenon and, if you want so, some other fuel but it is not possible to put just LFO in it.

Known issues
So far, I'm not aware of any issues but I've just tried my config on stock parts. It is possible that mod parts will behave differently.

Have fun

Download: https://www.dropbox.com/s/cil42bwhp4eyd25/[SFS]cheesecakes_alternative_config.zip?dl=0

Just thought I'd mention: Managing these types of configs is exactly what PatchManager was designed for:

 

[Snark]

31 minutes ago, RealKerbal3x said:

If this becomes a thing, I’d better learn how to make MM patches

Yeah.  If only this mod were produced by the kind of person who likes to document things and makes a point of providing helpful examples when new features get added. 

[RealKerbal3x]

1 minute ago, Snark said:

Yeah.  If only this mod were produced by the kind of person who likes to document things and makes a point of providing helpful examples when new features get added. 

Oops, missed that

I have literally zero experience in MM patches anyway, so I’m going to have to learn the syntax and everything.

[Snark]

7 minutes ago, RealKerbal3x said:

I have literally zero experience in MM patches anyway, so I’m going to have to learn the syntax and everything.

It's tons of fun.  (Well, for a very nerd-centric definition of "fun".)  It's amazing how much stuff you can do in KSP with just MM patches, not needing a single line of code.  Super powerful and flexible tool.  The syntax guide and handbook are good places to get started.  FWIW, though, when I enable the "no-resources" option, I expect I'll provide a sample .cfg file in the "examples" folder, and it might as well be the "Terrier shrouded variant has some fuel on it" one, so that'll give you most if not all of what you want anyway. 

[Deimos Rast]

Suggestion: add to Stratus Mono prop tanks?

[Snark]

Hi all,

I'm pleased to announce the release of SimpleFuelSwitch v1.1.1.  No new features as-default-installed, but this enables "no resources" as a switchable option for folks who are inclined to tinker with config.

This allows, for, example, @RealKerbal3x's suggestion of "what if you made it so that the shrouded variant of the Terrier had some LFO in it, like Porkjet's overhauled version".  I've also made available a sample config file that does just that-- it's not installed by default, but you can find it in the examples folder of the mod's github repository.

Thank you to RealKerbal3x for the feature suggestion! 

[Snark]

2 hours ago, Deimos Rast said:

Suggestion: add to Stratus Mono prop tanks?

No, for the "boutique" fuels like monoprop and xenon (i.e. the fuels that are only used by a small number of specialized engines), I like it as a game feature that they have their own dedicated fuel tanks.

My purpose in making this mod wasn't "let anything switch to anything", but rather, to fill a hole because the game had no LF-only fuel tanks in it for rockets.

Therefore, I won't be adding any switchable resources to anything other than the LFO and LF tanks, because in my own gameplay I don't want the other tanks to be switchable.

That said, though-- I made a point of making the mod's behavior be config-driven, so that it's really easy to add switchable resources to any part you want to, just with a snippet of ModuleManager config.  So if you want switchable monoprop tanks in your own game, this mod will totally let you do that-- just needs some config to make it happen.

[Snark]

Hmm. Just realized that there are legitimate cases where a part has resources other than the switched ones, and SimpleFuelSwitch is not playing nice with those (it wipes out the "extras"). Case in point, the conical Soyuz-style tanks from Making History have built-in sepratrons with a small bit of solid fuel... which gets wiped out by SimpleFuelSwitch.

So I'll need to do a bit of tinkering to fix that. As always, no promises on ETA, but it's on my radar.

[Gapone]

Please add resource amount and cost to part info panel (per option)

And make the part show its cost without resources (e.g. oscarb is 70vf fully fueled and ~52vf without fuel)

Or better make settings (where to show what and what to show where) (e.g. summary line: amount/mass/cost)

Edited January 23, 2019 by Gapone

[Behemot]

Thank you sir for the mod, makes many things much easier.

 

I do however have a question…why are the Mk 3 tanks removed? They may have the same volume, but slightly different shape than Rockomaxx, so…

 

Edited January 23, 2019 by Behemot

[4x4cheesecake]

39 minutes ago, Behemot said:

I do however have a question…why are the Mk 3 tanks removed? They may have the same volume, but slightly different shape than Rockomaxx, so…

I brought up the same question earlier:

On 1/10/2019 at 11:15 AM, 4x4cheesecake said:

Also, I have a suggestion: I can totally understand that you want to hide some redundant parts but since they got a different texture and the parts can still be used through the 'advanced mode', it would be nice to add the fuel switch feature to these parts as well, so if you want to use them for a different look, you can still switch the fuel
Also, is it intented that wings with fuel capacity are not able to switch the fuel? Would be nice for some spaceplanes

And the answer to this was:

On 1/11/2019 at 1:07 AM, Snark said:

Yeah, I thought about that.  However, I couldn't think of any cure that seemed unambiguously better than the disease, so to speak, which is why I didn't do this.

First of all, one thing that I'm absolutely not going to do is to add new settings or options UI or whatever to the mod to pick that sort of thing.  It's more code, more potential bugs, more maintenance hassle, for a feature that I myself would never use (nor, I suspect, would most users).  I really meant the "Simple" when I named the mod SimpleFuelSwitch. 

So the other alternative-- which would be simple and easy-- would be to add config to the parts that makes them switchable, and then hide them, so that if someone unhides them simply by deleting the relevant config file, they'd be all set.  However, even though it would be easy, it seems... kinda going out on a limb.  It would be making an assumption about what I think such a hypothetical person would actually want.  Why are they restoring the parts?  What do they want from them?  Do they want them to be switchable, too?  Do they want them in their original pristine state?  There's just no way to know, so I'd prefer not to address it at all.  If they want to add resources to them, then they can easily do so with a simple MM patch, basically just copy what I've done to some of the other LF-only tanks.

...Okay, quite a few more responses have piled up since I started typing this, gonna go ahead and post this before addressing the remainder.

TL;DR:

If you want them back and to have switchable resources, you have to do it on your own (but I can help you if you are not familiar with the MM syntax and how to write a MM patch)

 

[Snark]

23 hours ago, Gapone said:

Please add resource amount and cost to part info panel (per option)

 

Thank you for the suggestion, but no, I won't do that, because that's not how I want it to behave in my own gameplay.

Please bear in mind that I write mods for me, basically-- that's my motivation for modding in the first place, to make the game act the way I wish it would.  I mod because I play the game a lot, and little things bug me, and so I make mods to fix the things that bug me.  And then I share them publicly in case the stuff that bugs me might bug other people, too. 

I have two main rationales for why I designed it this way (i.e. just show the mass, not the extra details):

First, I'm primarily interested in the mass, anyway.  If I'm designing a rocket, and considering how to optimize dV or whatever, what I care about is how may total tons of propellant there are (since that's the only thing that's relevant to rocket physics).  How many "units" is completely unimportant and irrelevant to anything I do in-game.  Heck, it's always bugged me that I can't just glance at some random fuel tank and instantly see how many tons of fuel it has in it-- I have to do math every time (e.g. for an LFO tank, take the number of units of LF and divide by 90).  Since what I really want to see is the mass anyway, why show the units?  There's no reason.  (FWIW, I did put enough smarts into SimpleFuelSwitch so that if the resource in question is massless-- such as electric charge-- then it will show the number of units, rather than unhelpfully just saying "zero tons".)

"Okay," I hear you cry, "in that case, why not show the mass and the amount / cost?"

That brings me to my second reason for doing this, which is that I loathe clutter.  Can't stand it.  I want to play a carefully designed game that shows me exactly the information I want and nothing else whatsoever.  Showing the information I want (i.e. mass) as well as additional cluttery useless information like "how many units of LF and O" would be actively annoying to me.  This would be made worse by the fact that unlike the stock game-- which only has one resource option-- SimpleFuelSwitch shows all the options, so all that clutter would be multiplied and I'd have OCD conniptions.  It would be like sandpaper on my soul every time I go into the VAB.  And the whole point of this mod is to make me feel better about building ships, not worse.

"Well then," a reasonable person might ask,

23 hours ago, Gapone said:

Or better make settings (where to show what and what to show where) (e.g. summary line: amount/mass/cost)

^ Now that is actually a pretty reasonable suggestion, and in fact I considered doing just that when I was first implementing the mod.  After all, not everyone wants the same things as me, so why not allow people to customize it so it's just how they like it?

Well, it's not a total showstopper; it's entirely possible that someday I might consider such a feature.  But I gotta say it's way down on my priority list, so don't expect any feature like this any time soon, unless someone comes up with a reason for it that makes sense to me, personally. 

Reasons why it's not a priority for me:

• It's a feature that I myself would never use (since it's already behaving exactly the way I like it).  My free time is scarce and precious, so I have very little motivation to spend hours and hours working on something that I neither need nor want.
• Like all programming tasks, it would be time-consuming to write, test, debug, etc.  This is not a quick five-minute no-brainer.  So there needs to be a pretty strong reason to add it, to make it worth my while to spend the time on it.
• It's not at all clear that there's much demand for such a feature.  SimpleFuelSwitch itself is not all that popular a mod (it's already been out a few weeks, with several version releases, and has yet to hit even a thousand downloads-- I have other mods that have been out for years and still get many times more downloads per day than SFS does), so even if everyone using the mod wanted this, the total number of people involved is not all that huge.  And I'm guessing that probably 90%+ of SimpleFuelSwitch users don't even care all that much about this issue-- obviously you do, and I don't mean to make light of that, but you're just one person.  So, for me to even consider working on a feature that I myself have no use for, there would have to be convincing evidence of overwhelming demand, and I'm just not seeing that.
• Even if I did decide to put in such a feature, it's not at all clear how it should work, i.e. what the semantics would be.  Off the top of my head, I can think of about half a dozen different designs, which would please different people who want different things.  And there's no way of knowing what people would actually want-- or even whether most people actually want the same thing.  The result would be a sad chimera rather than a tight, well-crafted gem.  My experience has been that anything that's designed based on vague assumptions of what people want, without actually knowing, generally turns out to be a lackluster and slipshod-looking design that ends up pleasing nobody.  At least one thing I have going for me, when I design by my principle of "ignore everyone else and just design for me", is that I know very well what I like and therefore when I design for that, I totally nail the design.  Which means I will delight not only myself, but also anyone who likes the same thing I do.  I would rather delight a small number of people than to get a big crowd to go "meh". 

So, no, not happening any time soon, unless something happens that changes my mind.

23 hours ago, Gapone said:

And make the part show its cost without resources (e.g. oscarb is 70vf fully fueled and ~52vf without fuel)

Yeah, I'd actually like to do that, but unfortunately thus far I haven't been able to figure out how to make it do that, because as far as I can tell, this aspect of the game is implemented in a bass-ackwards way that seems to be preventing me from doing it.  Technobabble in spoiler, for the curious.

Spoiler

So.  Parts have some inherent cost, even if they're empty of resources.  And resources (such as fuel) have a certain amount of cost per unit, so when you "buy" a part by putting it on your rocket, the cost of the ship will be the sum of the "dry" cost plus the cost of the fuel.  Sounds simple, right?

So let's talk about how this would be implemented in the game, in any sane universe.  You'd have part config which specifies the dry cost of the part.  And then what the game would do, when displaying cost in the parts panel in the vehicle editor, would be to do some basic math:  take the configured dry cost of the part, add the cost of the resources that would be added to it by default, and then display that in the "cost" field of the part's info panel.  I mean, obviously.  Right?

Except that's not how KSP does it, as far as I can tell.  It's totally bass-ackwards.

What they've done is to have the part config show the full cost of the part, including the default resources, and they treat that as a "base" from which all other calculations are made.  If you place the part without altering the fuel amount, then it costs exactly what the part config says it will.  If you increase it, the part gets more expensive; if you decrease it, the part gets cheaper.

So why is this a problem?  Let's look:

Consider the fact that liquid fuel and oxidizer do not cost the same amount.  Oxidizer is cheaper.  So if you switch an LFO tank to be LF, it ought to get more expensive, right?

So let's think about how this would work in a sane universe:  the configured cost of an Oscar tank would simply be 52 funds (the "dry" cost), plus cost of resources.  So if you add it with an LFO mix, it costs 70, but if you switched to LF, it would be more expensive.  Right?

Wrong.

Because of the bass-ackwards implementation, the config says "the default cost of this tank is 70, regardless of what resources are configured".  So, if you add it with a full load of LFO (the default), it costs 70.  If add it as an LFO tank, empty, then the cost goes down to 52.  If you switch it to LF-only and launch with a full load... the cost stays at 70.  And if you switch it to LF and launch empty... the cost is actually LESS than 52, because LF is more expensive, and you've subtracted more-expensive LF instead of subtracting less-expensive LFO.

It's stark raving silly.  But I haven't been able to figure out a way around it, short of configuring all the tanks to be empty by default, which obviously no player would want.

Also, note that as far as I can tell it's impossible to get the "Cost" field to show the dry cost of the part, because the game has no concept of any such thing as a "dry" cost, and KSP will always show the full cost.  Maybe there's some hook somewhere that would let me override KSP's default behavior there, but if so, I haven't been able to find it yet.

So, that's why it does what it does-- not because I like it, but because the game makes things difficult in a way that I haven't been able to figure out how to work around.

(By the way-- although I keep describing the behavior as "bass-ackwards" in an irritated manner, please note that I never use the word "stupid".  The KSP implementation is a perfectly reasonable way to do things, if you're assuming that resources don't get switched from what the config says.  My guess-- and this is just wild unfounded speculation on my part, here-- is that whatever KSP devs originally coded this, they simply didn't anticipate that a mod would want to be dynamically switching out resources.  I ran into a bunch of pain points like this in the process of coding this mod-- I felt at several points like I was "fighting" the game, because it has this "resouces configured on a part are static" assumption built in at so many places.  So please don't read the above as an anti-Squad rant.  It's not a stupid design.  It's just a design that failed to anticipate a moddability concern, which is an entirely understandable thing.  Nobody can anticipate everything-- and I wouldn't be surprised if the resource-handling code might be some of the oldest in the game.  So I'm not complaining, here-- merely observing that it makes what I'm trying to do more difficult than I expected.)

I'd love it if there turned out to be some way to make it do what I want in this regard, but have drawn a blank thus far.  If anyone knows a way around the technical impasse described in the above spoiler, please let me know!

18 hours ago, Behemot said:

I do however have a question…why are the Mk 3 tanks removed? They may have the same volume, but slightly different shape than Rockomaxx, so…

Because they're redundant and unnecessary and I hate clutter so I like to remove redundant / unnecessary things.

Note that Rockomax tanks are completely irrelevant to this discussion, here, so let's just set those aside.

The thing is:  there's a family of Mk2 and Mk3 fuel tanks, such that there are "twin" tanks.  What I mean by that is, there are some LFO fuel tanks in Mk2 and Mk3 sizes, and there are exactly identical LF-only tanks that have the same shape, size, mass, and fuel capacity as the LFO version.  The only difference is the fuel type that they contain.

As an example of such a "twin" pair, consider the Mk3 Rocket Fuel Fuselage Short, and compare that with the Mk3 Liquid Fuel Fuselage Short.  I mean, look at them.  It's the same darn tank.  They're absolutely identical... except that one has LFO and the other has LF.

It made sense to have both flavors, in the stock game where you can't switch resources.  Because some craft need an LFO tank, but others need an LF tank.

But if you're running SimpleFuelSwitch, where any of these tanks can be switched to have either LFO or LF as desired... then there's no point in having "twin" tanks like this anymore.  So I've removed the redundant ones.  For example, in the above pair, I've removed the Mk3 Liquid Fuel Fuselage Short, because nobody needs it:  if you want that part, just use a Mk3 Rocket Fuel Fuselage Short and switch it to LF.

And if, by the way, anyone doesn't like that decision and wants them back?  No problem.    Just read what I wrote in the OP of this thread:

On 1/9/2019 at 7:42 PM, Snark said:

Other part changes

A few fuel tanks have been removed, now that this mod has made them redundant.

Rationale:  With this mod, pretty much every stock LFO tank can now be LF if you want, and vice versa.  This means that there are some stock KSP tanks that are now completely superfluous-- i.e. there are a few cases where there are two stock tanks that are completely identical except for having one be LFO and the other be LF. With this mod in place, there's no longer any point to having such duplicates, so in the interest of removing part-tab clutter, these redundant parts have been removed.

Removed parts include the Mk1 Liquid Fuel Fuselage, the short and long Mk2 liquid fuel fuselages, and the short, medium, and long Mk3 liquid fuel fuselages.

(If you don't like that, you can just delete the Hide_redundant_parts.cfg file to restore them.)

 

[Behemot]

I totaly understand the duplicit parts, the short fuselage are the same so sure. What I mean are the large ones, what's the name…ah, here: Mk3 Liquid Fuel Fuselage Short, Mk3 Liquid Fuel Fuselage, Mk3 Liquid Fuel Fuselage Long. I would understand if you removed these three, but I can not find the Mk3 Rocket Fuel Fuselage either, I mean, the whole family is gone. But this Mk3 thing has different shape and thus also different volume than Rockomaxx tanks. They are not the same parts! Kinda miss those. I do not want the duplicit parts - just these Mk3 Fuselage tanks…

 

Edited January 24, 2019 by Behemot

[Snark]

38 minutes ago, Behemot said:

I would understand if you removed these three, but I can not find the Mk3 Rocket Fuel Fuselage either, I mean, the whole family is gone.

Wait, what?  That sounds wrong, that's not my intent at all.  They should still be there.  If they're gone, then either you've made a mistake somewhere, or else I goofed and removed something I didn't mean to.

I could totally believe it's a bug on my part (it has been known to happen) ... but unfortunately I'm not at my KSP computer right now and therefore can't directly check it myself.

Though honestly, if the LFO versions did somehow get removed too, I'm honestly baffled how that could be possible, or how I would fix it if so.  Here's the actual config that does the part-removing.  Note that it specifically addresses the parts to remove, individually, by part name, and the only ones listed there are the LF-only versions.  So no other parts should be affected.

Also, there have been a few hundred people using the mod thus far... if I really were throwing out all those additional parts somehow, I would have thought someone would have mentioned it by now.  (Especially since the part-removal design decision has been discussed here by people who do use the parts in question, so I assume they would have noticed if there were a problem?)

[4x4cheesecake]

I just checked it, the MK3 LFO tanks are still there and are not removed by this mod. It's pretty much impossible to remove them accidentally since the MM patch does not use any wildcards and adresses the parts by name:

@PART[MK1Fuselage|mk2FuselageShortLiquid|mk2Fuselage|mk3FuselageLF_25|mk3FuselageLF_50|mk3FuselageLF_100]

Even the partnames just got LF in the name, not LFO.

If the parts are missing, it is a different mod, a corrupted game which misses some files or anything else.

@Behemot Can you access the MK3 LFO tanks in the advanced mode of the editor (hit the arrow shaped triangle in the upper left corner)? If not, please check your gamefiles if you got any LFO_*.cfg, LFO_*.mu files in this directoy:

Kerbal Space Program\GameData\Squad\Parts\FuelTank\mk3Fuselage

You can also check your ModuleManager.ConfigCache by opening it in a texteditor and search for "mk3FuselageLFO_25" or any other MK3 LFO tank name.
If you can find an entry in the configcache, check also for the 'category' and 'TechRequired' entry. Everything except for 'none' should be fine.
If you don't feel confident to look at the configcache, you can also upload it and share a link here and I'll take a look at it.

[Behemot]

Got this:
 

Kerbal Space Program\GameData\Squad\Parts\FuelTank\mk3Fuselage

In MM cache:

UrlConfig
{
	name = mk3FuselageLFO_25
	type = PART
	parentUrl = Squad/Parts/FuelTank/mk3Fuselage/LFO_25
	PART
	{
		name = mk3FuselageLFO_25
		module = Part
		author = Porkjet
		rescaleFactor = 1.0
		node_stack_top = 0.0, 1.25, 0.0, 0.0, 1.0, 0.0, 3
		node_stack_bottom = 0.0, -1.25, 0.0, 0.0, -1.0, 0.0, 3
		node_attach = 1.63, 0.0, 0.0, 1.0, 0.0, 0.0, 1
		TechRequired = experimentalAerodynamics
		entryCost = 21000
		cost = 2500
		category = FuelTank
		subcategory = 0
		title = Mk3 Rocket Fuel Fuselage Short
		manufacturer = C7 Aerospace Division
		description = A compact fuel tank for when the rest of your craft is taken up by cargo bays!
		attachRules = 1,1,1,1,0
		mass = 1.79
		dragModelType = default
		maximum_drag = 0.2
		minimum_drag = 0.3
		angularDrag = 1
		crashTolerance = 50
		maxTemp = 2700
		emissiveConstant = 0.87
		fuelCrossFeed = True
		bulkheadProfiles = srf, mk3
		breakingForce = 300
		breakingTorque = 300
		tags = fueltank ?lfo liquid oxidizer propellant tank
		MODEL
		{
			model = Squad/Parts/FuelTank/mk3Fuselage/LFO_25
		}
		MODULE
		{
			name = ModuleSimpleFuelSwitch
		}
		MODULE
		{
			name = ModuleSwitchableResources
			resourcesId = liquid_fuel_oxidizer
			displayName = LFO
			selectorFieldName = Fuel Type
			isDefault = true
			RESOURCE
			{
				name = LiquidFuel
				amount = 1125
				maxAmount = 1125
			}
			RESOURCE
			{
				name = Oxidizer
				amount = 1375
				maxAmount = 1375
			}
		}
		MODULE
		{
			name = ModuleSwitchableResources
			resourcesId = liquid_fuel_only
			displayName = LF
			selectorFieldName = Fuel Type
			RESOURCE
			{
				name = LiquidFuel
				amount = 2500
				maxAmount = 2500
			}
		}
	}
}

 

However, nothing in the game (not in space plane hangar either), can I upload an image here around it somewhere?
 

There is at least one existing tank in the game on my Mun space station which fortunatelly have not disappeared or bursted into flames. But I can not see any such part in the part menu in the hangar editor.
 

Edited January 24, 2019 by Behemot

[4x4cheesecake]

52 minutes ago, Behemot said:

However, nothing in the game (not in space plane hangar either), can I upload an image here around it somewhere?
 

There is at least one existing tank in the game on my Mun space station which fortunatelly have not disappeared or bursted into flames. But I can not see any such part in the part menu in the hangar editor.

Odd...especially since you got a vessel in the game which actually got the part. The configcache looks fine though.

You cannot upload a picture to the forum, you need an external hoster like imgur, afaik, you don't even need to create an account there. Maybe take a look into this thread for more details

Edited January 24, 2019 by 4x4cheesecake

[Behemot]

Could that actually be the problem? That I have the LFO Mk3 Fuselage and it has been removed, so it conflicts and makes the rocket fual variant Mk Fuselage disappear?
 

Looky:
 

Edited January 24, 2019 by Behemot

[4x4cheesecake]

14 minutes ago, Behemot said:

Could that actually be the problem? That I have the LFO Mk3 Fuselage and it has been removed, so it conflicts and makes the rocket fual variant Mk Fuselage disappear?

I have a different guess:

The part list is quiet empty so I assume this is a career savegame. The MK3 LF tanks are unlocked one node earlier then the MK3 LFO tanks (LF tanks in Heavy Aerodynamics, LFO in Experimental Aerodynamics) Since I cannot see any other part from the Experimental Aerodynamics node like the MK3 MonoProp tank or the MK3-MK2 Adapter, I have to assume that you just didn't unlock the node so far.

The MK3 tank on your Mun station: Is it really the LFO version or the LF version?

Just to be sure: create a sandbox savegame and check if the tanks appears in the part list.

[Behemot]

Right you are! I got the LF unlocked (and now removed) and the RF (LFO) not yeat reasearched, it is the "Experimental Aerodynamics" node.
 

[4x4cheesecake]

14 minutes ago, Behemot said:

Right you are! I got the LF unlocked (and now removed) and the RF (LFO) not yeat reasearched, it is the "Experimental Aerodynamics" node.
 

Great, this can be easily fixed To move the LFO tanks to the same node where the LF tanks are located, create a textfile within your GameData folder, name it however you want but be sure that it got the .cfg file extension. Than add these lines to the file, save it and restart the game:

@PART[mk3FuselageLFO_25,mk3FuselageLFO_50]:AFTER[SimpleFuelSwitch]
{
	@TechRequired = heavyAerodynamics
}

Keep in mind that the biggest MK3 LF tank is in the Experimental Aerodynamics node by default, so the biggest LFO tank will not be moved.

@Snark You may want to add this patch to your mod as well, otherwise a career game needs to unlock an additional tech node to actually get any MK3 fuel tanks.

Edited January 24, 2019 by 4x4cheesecake

[Snark]

What?  They actually put them on different-tier tech nodes?  How utterly silly.  That seems like an... odd... game-balance decision.

(You can tell that I'm not a spaceplane guy-- I didn't notice this because I never, ever under any circumstances use those fuel tanks.  That's why I made this mod, because those tanks are a form factor that's useless to me because I build rockets, not spaceplanes.)

Anyway, that explains it.  Thanks for the investigation, @4x4cheesecake!  I expect I'll just tweak things to move them appropriately as suggested.

[Behemot]

I only use it rarely on Kerbin to collect some science, but will likely make some of that for some fun on other objects with atmosphere, si it may come in handy  Don't need it right away so I'll just research it later, np.