Should KSP have a Delta-V readout?

[razark]

The reasoning was something along the lines that it would take away all the fun of repeatedly failing if you actually knew the numbers.

[soulsource]

If you want to get an idea of how complex it is to implement dV readout for an arbitrary vessel, feel free to have a look at the KER source code, more precisely at the VesselSimulator. Also, please consider, that while KER is pretty good at dV calculation, it still fails now and then for particularly convoluted craft designs (what's perfectly find for a mod, but would cause dozens of flame-threads in this forum if it were stock)...

Sadly, this means that without mods you have to calculate dV manually using the mass readout of the VAB. For each stage, you can write down the mass with full, and empty fuel tanks (right click menu of the tanks...), and the input this, together with the I_sp of the stage's engines in the rocket equation. Just don't forget to set the tanks to full afterwards, or you might have a nasty surprise...

[Gojira1000]

Put it this way, though: In going to console, Squad will have to include some form of dV readout. I'd hazard a guess that a vast majority of players use some dV readout mod at the moment.

Console won't do well without one, IMO.

[razark]

6 minutes ago, Gojira1000 said:

In going to console, Squad will have to include some form of dV readout.

I think Squad has adequately shown that just because something appears to be a really good idea to a large number of players, they don't have to do it.

[Cornholio]

From what I understand, there are still some hardcore players that enjoy calculating dv through pencil & paper or spreadsheets.  I always assumed that because of this and that mods like KER are constantly updated for patches, this gives the player both options.

[Gojira1000]

18 minutes ago, razark said:

I think Squad has adequately shown that just because something appears to be a really good idea to a large number of players, they don't have to do it.

Thus the second statement: Console won't do well without one, IMO.

[razark]

1 minute ago, Gojira1000 said:

Thus the second statement: Console won't do well without one, IMO.

Well, the way that some players treat it as a wacky lolsplosion murder simulator, I think Kerbal Space Pogrom will do fine on consoles without delta-V readouts.

[regex]

2 hours ago, eberkain said:

I was going to play the game with no mods at all, and I just can't get past the fact that there is no Delta-V estimation or TWR value for each stage.   The game is basically just trial and error with no real information to base your changes on.

Nonsense.  The game gives you enough information to calculate those values yourself in multiple places.

2 hours ago, eberkain said:

I just want a strait answer for what the reason is for not including this information in the base game?

It's a very tough thing to do.  Kerbal Engineer and MechJeb get it wrong all the time, odd combinations of parts can easily confuse the calculator on those mods.  I can't count the number of times either has freaked out from my strange staging or part arrangement.  If that were a stock feature the sheer number of complaints about it would overwhelm the forums.

[Gordon Fecyk]

Doesn't the vessel information window in the Map view already show estimated acceleration (in m/s²) and then estimated time to 0 m/s in seconds? Multiplying those numbers gives you estimated delta-v in m/s. Granted, that's an estimate for the current stage and not extrapolated per-stage.

6 minutes ago, razark said:

I think Kerbal Space Pogrom will do fine on consoles

Now I have heard, "Jeb is love, Jeb is life," once, but I'm really hoping this is a typo. (I'll get my coat...)

--

[Andem]

Well, IIRC, trial and error is part of the point. I think it was @Snark that said that it changes the game from a Trial & Error experience to an Engineering experience, and that they play completely differently. If you want to play an Engineering game, Get a calculator or KER. Until it happens, which it probably will regardless, those are your options.

[Rocket In My Pocket]

I hear the "trial and error" is fun reasoning come up a lot, as well as "too many numbers would scare new players off."

My idea to solve this while still providing a rough estimation of Dv display was always a sort of color coded Delta V tree with no numbers of any kind as well as your rocket's potential Dv displayed for comparison via it's own line.

This would leave some ambiguity while still providing players with feedback. Here is a very quick and rough mock up of what I'm talking about I threw together in paint with an existing Delta V map:

This tells me my example rocket can almost reach the Mun, but definitely can't reach Minmus in an easy to read at a glance format, obviously it would be way more polished than this but you get the idea.

Edited June 14, 2016 by Rocket In My Pocket

[Snark]

53 minutes ago, Andem said:

Well, IIRC, trial and error is part of the point. I think it was @Snark that said that it changes the game from a Trial & Error experience to an Engineering experience, and that they play completely differently. If you want to play an Engineering game, Get a calculator or KER. Until it happens, which it probably will regardless, those are your options.

I vaguely recall the thread you mention-- I think it was someone else who chimed in with "these additional mods change it from trial & error to an engineering game", and I simply chimed in with "don't need the mods, can use a calculator for the simple stuff, don't even need a spreadsheet."    But I fully recognize it as being not everyone's cup of tea.

1 hour ago, regex said:

It's a very tough thing to do.  Kerbal Engineer and MechJeb get it wrong all the time, odd combinations of parts can easily confuse the calculator on those mods.  I can't count the number of times either has freaked out from my strange staging or part arrangement.  If that were a stock feature the sheer number of complaints about it would overwhelm the forums.

^ This.  Getting a dV display right is really hard.

I discovered this when I implemented BetterBurnTime.  It's a much simpler mod than KER or MechJeb, and only solves a tiny subset of the problem and doesn't even attempt to deal with staging.  And even going that far turned out to be a lot more complex to code than I anticipated.

MechJeb and KER are hugely complex mods into which a lot of effort has been poured.  They've been around for years, and have still not got it perfect, as regex points out.

This means for Squad to implement this functionality would be a great big chunk of their time (which they could have spent on something else), and still is likely to run into problems that will lead to firestorms of "it's wrong!" complaints.  Better left to MechJeb and KER, as far as I'm concerned.

[regex]

1 minute ago, Snark said:

Better left to MechJeb and KER, as far as I'm concerned.

Much as I consider delta-V calculation to be a vital part of gameplay in KSP I also feel this is the best solution.  It's not that I don't think Squad could do it, it's just that, with the stock/vanilla game, it has to be done right pretty much the first time, with the vast majority of edge cases resolved before it's even considered for release.  Mod authors can afford a much more loose development and release schedule, and have much more freedom in terms of when and how to release a new update.  Squad can't afford those luxuries.

[Guest]

If every feature in the KSP stock game was withheld until the vast majority of edge cases were resolved, we wouldn't have many of the features we currently enjoy. Make no mistake about it, the only reason a simple form of dv readout isn't already in the game is because Squad doesn't want it there, which is perfectly fine with me. It will be nice however when the random VAB crash issue is resolved, so I can put the readout mods in when I'm ready without having to worry about it.

[Red Iron Crown]

On 6/14/2016 at 2:52 PM, eberkain said:

I just want a strait answer for what the reason is for not including this information in the base game?

The canonical answer is HarvesteR felt it removed too much uncertainty from the game.

On 6/14/2016 at 4:50 PM, Gojira1000 said:

I'd hazard a guess that a vast majority of players use some dV readout mod at the moment.

You'd be guessing wrong. Squad's own internal data showed that only a minority of players use mods at all (I can't seem to dig up the reference for this, I distinctly remember it because I found it surprising, too). Most players play stock.

Personally, I think some sort of delta-V meter should be added to stock. People who don't want it can just not use it, while those who do can benefit from it. It doesn't have to be perfect (and very likely won't be, there are a *lot* of edge cases), it just needs to handle most cases well enough until a player becomes experienced enough to figure out when it's going wrong. Even just handling the simple, serially staged case would be a big step forward.

The game purports to be educational about rocket science out of one side of its mouth while ignoring the two most important numbers in spaceflight, TWR and delta-V.

On 6/14/2016 at 5:31 PM, Gordon Fecyk said:

Doesn't the vessel information window in the Map view already show estimated acceleration (in m/s²) and then estimated time to 0 m/s in seconds? Multiplying those numbers gives you estimated delta-v in m/s.

No, it doesn't. That calculation would give an approximation of the vessel's current velocity.

[Andem]

On 6/14/2016 at 4:09 PM, Rocket In My Pocket said:

I hear the "trial and error" is fun reasoning come up a lot, as well as "too many numbers would scare new players off."

My idea to solve this while still providing a rough estimation of Dv display was always a sort of color coded Delta V tree with no numbers of any kind as well as your rocket's potential Dv displayed for comparison via it's own line.

This would leave some ambiguity while still providing players with feedback. Here is a very quick and rough mock up of what I'm talking about I threw together in paint with an existing Delta V map:

This tells me my example rocket can almost reach the Mun, but definitely can't reach Minmus in an easy to read at a glance format, obviously it would be way more polished than this but you get the idea.

This would be a great middle ground in my opinion, but would also take the same time and effort to implement it.

[Tourist]

Long time player here (of the game, of course, not of the affections of lovers)

I've been pretty much everywhere in the Kerbol system except Eeloo, and I've never used a Delta V calculator. It is entirely possible to play without one, you just have to over-engineer the heck out of everything... and learn from failed attempts. Once you have ISRU you don't even have to over-engineer that much anymore. 

That being said, I've recently begun toying around with KER. Its great, but I've actually found the function I like more than the Delta V calcualator is that it tells you your AP so I can launch entirely from the ship view.    

Edited June 16, 2016 by Tourist

[icedown]

I definitely agree that dV and TWR should be available in the stock game.  Back when it was just throwing a bunch of parts together and watching them explode beautifully and occasionally actually making it to orbit was one thing.  With career mode and new aerodynamics, it's almost a must. I know I could never afford to go career mode without the ability to revert if it wasn't for KER

Edited June 16, 2016 by icedown

[Gojira1000]

28 minutes ago, Red Iron Crown said:

You'd be guessing wrong. Squad's own internal data showed that only a minority of players use mods at all (I can't seem to dig up the reference for this, I distinctly remember it because I found it surprising, too). Most players play stock.

 

I would be shocked - though perhaps that is the case. I suppose there could be many who played KSP without - I wonder if many of those hang around long term? Not that duration matters from a sales perspective. Though that may make sense - the actual number of players who get further than Minmus (as a percentage of units sold) might surprise me, too.

Now I want statistics

[Red Iron Crown]

1 minute ago, Gojira1000 said:

I suppose there could be many who played KSP without - I wonder if many of those hang around long term?

I would imagine that length of time played correlates pretty well with mod use (though there will of course be the outliers, people who mod it up before even loading it and those long term stock players).

Quote

Now I want statistics

Would be nice, but the way some people twist any numbers from Squad helps me understand why they keep mum on them.

[StrandedonEarth]

25 minutes ago, Red Iron Crown said:

It doesn't have to be perfect (and very likely won't be, there are a *lot* of edge cases), it just needs to handle most cases well enough until a player becomes experienced enough to figure out when it's going wrong. Even just handling the simple, serially staged case would be a big step forward.

I think this is all that's really needed. A simple, serially staged rocket could get a green dV readout, indicating that the calculator is confident that the number is correct. A more complicated setup could get a yellow readout, indicating that the calculator *thinks* it has the correct answer. For really weird rockets, the readout would be red, indicating that the calculator is pretty much just guessing.

Of course, the real trick would be having the calculator figure out how confident it is with the answer. I've noticed the best/easiest way to mess up the KER code is to have the root part in the middle of the stack!

One idea that comes to mind for simplifying some of the odder cases (like my 6-pack of Joolian probes) might be the ability to designate a subassembly as 'payload' and have it removed from further dV calcs. When building the payload you could see how much dV the payload has, but once 'shrouded' it gets removed from further calculations, making it easier to figure out the rest of the stack. Just a random thought.

 That leads to the real crux of the matter: when the dV calculator gets confused, one simply has to look at the different sections of the rocket and make sure that each section has the dV to do the job it needs to do, whether landing, ascent, transfer, insertion, or whatever combination of those. Although I'm sure someone has built a single stage with an odd enough configuration of engines, angles, tanks, and fuel lines to leave a calculator smoking its circuits in confusion.

[mattinoz]

On 15/06/2016 at 4:16 AM, kcs123 said:

I think it is pointless to discuss about this topic because it is already planed to include dV readings in stock game. If you can trust post in common suggestion thread.

Probably threre is good reason why it is not already included in game. like more important bugs to squeeze out before adding new feature in game. Just have to be patient until it become part of stock game and use MJ or KER mod until then.

The last semi-offical comment was by memory from NathanKel  in this thread. 70330-should-ksp-have-a-delta-v-readout but it was very much along the lines of this summary....

On 15/06/2016 at 3:44 AM, 5thHorseman said:

It's really hard to get perfect, and if it's not perfect more people will complain about it being not perfect, than complain now about it being non-existent.

So unless as a community we get vocal about an acceptable way to piecemeal development and have vague results that improve over time so the code doesn't have to deal with every/any edge case on day one then I suspect it'll be something in train for many many many releases to come.

[pincushionman]

The "most players don't use mods" statement is probably true. But if we qualify it: "most players that use mods use informational mods like KER"…well, that's probably not true either, but it's more believeable.

As for the OP's question - I believe recent (but not official!) posts by devs have indicated that such a feature is planned, but other things^TM were more important at the time the statements were made. And since the Unity 5 transition still has serious issues, that is still true right now. I'd say after wheels work again we get to start bugging them about this. I'll eat my hat if it's in 1.2.

Edited June 16, 2016 by pincushionman

[mattinoz]

9 minutes ago, StrandedonEarth said:

I think this is all that's really needed. A simple, serially staged rocket could get a green dV readout, indicating that the calculator is confident that the number is correct. A more complicated setup could get a yellow readout, indicating that the calculator *thinks* it has the correct answer. For really weird rockets, the readout would be red, indicating that the calculator is pretty much just guessing.

This would be good for breaking up the development.

Start with everything red meaning basically raw math calculation. Round two add a test system that flags edge cases. Pass all the tests the reading turns green. Round three a failed test triggers a specific calculator which then gives an orange reading.

[GoSlash27]

I second what @regex said.

 KSP is actually an educational program masquerading as a toy. If you want to know the t/w and DV, it's a simple matter to calculate it from the available information.

  Pretend you're a rocket scientist and figure it out. It's much more fun that way!

 

Best,

-Slashy