Developer Insights #21 - Rockets' Red Glare

[RocketRockington]

32 minutes ago, Strawberry said:

The colony image mentions using water as a heat sink here, and it lists contact with surface should conduct heat.

That's explicitly not thermal conductivity between parts, which your imaginations on more interesting colony design is based on.  That's 'this radiator only works when it's touching water'.    The most dumbed down answer to how things are going to work is clearly the design path they're going for - they rejected any environmental modifiers to how space radiators work, in favor of a flat 'this radiator does this many watts of cooling' so why would they include a bunch of complication to colony radiators?

  I'll bet you real money that the colony based heat system isn't any more interesting than the space based one, just parts that generate heat, and parts that dissipate them, and the only 'interesting' gameplay is doing the arithmetic to see if B > A, as is clearly spelled out in the dev blog. 

If colonies ever come out that is 

Edited July 21, 2023 by RocketRockington

[Strawberry]

4 minutes ago, RocketRockington said:

That's explicitly not thermal conductivity between parts, which your imaginations on more interesting colony design is based on.  That's 'this radiator only works when it's touching water'.    The most dumbed down answer to how things are going to work is clearly the design path they're going for - they rejected any environmental modifiers to how space radiators work, in favor of a flat 'this radiator does this many watts of cooling' so why would they include a bunch of complication to colony radiators?

  I'll bet you real money that the colony based heat system isn't any more interesting than the space based one, just parts that generate heat, and parts that dissipate them, and the only 'interesting' gameplay is doing the arithmetic to see if B > A, as is clearly spelled out in the dev blog. 

If colonies ever come out that is 

All of my examples were referring to thermal conductivity with the ground (and also sun heating up parts), and were emergent from that. 

Edited July 21, 2023 by Strawberry

[Nertea]

  An overall question I'd like to answer is whether you feel like this dev blog was a useful thing for me to put together. Given that my role on the KSP2 team is as a designer, I'm limited in what I can write about, and thought I'd try a long-form design document. If it was informative and interesting to read, I've accomplished my goal, but it is quite a time sink to write long things. 

Just now, moeggz said:

Here we have it. Confirmation that they’re are still in the conception phase, at least partially.

Well, I believe the devlog is pretty clear about allocating the radiator stuff for release around the Colonies update there  . 

8 minutes ago, cocoscacao said:

Wait... This is gonna be a thing? Base building sounds awfully more fun now

These are EXACTLY the stories I am excited about with this system. Reentry can be an interesting challenge, but ultimately it gets solved the same way every time - you use a heat shield or you keep your speed low - hard IRL, trivial in KSP. When you get that complex environmental context going, you start to have more options and trades to make about where you site something. 

Ultimately I'd eventually like thermals to be as varied as engines in terms of problems to overcome. Just like engines have different situational uses and different requirements around sizes and fuel types, different cooling methods and approaches should be valid in different situations. 

19 minutes ago, Sesshaku said:

As far as I understood it, multiple radiators in weird angles radiate heat to each other reducing efficiency. Will inter-reflection be included in the "deterministic" simulation? @Nertea

I'd place that in the 'computationally complex and challenging to make performant' category. 

32 minutes ago, RocketRockington said:

Your system also resolves to 'blow up if not enough radiators, perfectly cool if enough radiators' so I don't see your objection here being valid at all. 

At least with conduction, some consideration of where and how parts are placed is a thing, which isn't the case under this extremely unrealistic heat model.

Fair. And I'd take the simpler system any day, if it will be computationally more efficient - I'm sure we can agree that performance is something we need to be cognizant of. 

I would generally argue that heat in KSP1 has no practical utility outside of reentry and stars, because it vanishes when a vessel isn't focused, and reverts to analytic mode when you're over 1000x warp anyways, which disables conduction and replaces it with an approximation. The system is tuned so that the only time a player needs to interact with it is during reentry and atmospheric flight, which it succeeds very well at (this ignores the core heat system that runs drills and such which is completely different). I'd like to do better than that. 

I doubt we'll convince each other here, but I hope we can demonstrate that as we deliver the system over the next few milestones that it makes for interesting gameplay. 

 

[moeggz]

@Nertea 

I think it was useful. I like the new direction in thermals and am excited for those new systems as they are expandable to the new scale of KSP2.

To be completely clear, my criticism was to the marketing of the game. This update was nice. It would have also been nice for it to have been clear 5 months ago how much still needed to be done here, but that’s not your fault

so thanks for the update, I enjoyed reading it and look forward to seeing it in action.

[Scarecrow71]

57 minutes ago, Strawberry said:

The colony image mentions using water as a heat sink here,

Hold the phone.  Are we going to have to deal with heat in colony management?  If so this game is going farther and farther away from building rockets, and I'm not sure I want any part of it any longer.

[RocketRockington]

21 minutes ago, Strawberry said:

All of my examples were referring to thermal conductivity with the ground (and also sun heating up parts), and were emergent from that. 

1 hour ago, Strawberry said:

There also could be some fun stuff when it comes to minimizing heat transfer from the sun too, for example if youre in a tidally locked planet, all you really care about is one face of your colony, meaning your colony may end up being basically a straight line to minimize transfer from the heat

These two statements do not go together.   And also Nertea's diagrams do not show anything related to thermal flux coming from the ground in general, or the air in general, when it comes to colonies.  Or anything where any part considers its contact patch, its occluded area, etc.  Read through the design again, you'd need some major additions/complications to it to support any of the things you mention.

[Strawberry]

18 minutes ago, RocketRockington said:

These two statements do not go together.   And also Nertea's diagrams do not show anything related to thermal flux coming from the ground in general, or the air in general, when it comes to colonies.  Or anything where any part considers its contact patch, its occluded area, etc.  Read through the design again, you'd need some major additions/complications to it to support any of the things you mention.

How dont the two statements go together? The second example is literally talking about minimizing the amount of sunlight that hits your colony as thats emergent from sunlight heating up parts. Also yes, the diagrams only mention thermal flux from fluid, however the diagrams are not the entire dev post??? It literally explicitly mentions several times about how the ground, and atmosphere will mess with your thermals. For example:

Spoiler

• Reentry and atmospheric heating on planets with atmospheres
• Environmental heat sources and sinks (oceans, etc.) that can affect vessels and colonies. 

There are three processes that can do this: convection, conduction and radiation. Convection is a very effective way of dispersing heat, using atmospheric or fluid currents to move heat away from a heat object. Conduction is also efficient and relies on two objects touching – heat will flow from the hot to cold object. Radiation is the least effective way of dispersing heat and relies on the tendency of hot objects to emit photons, which carry away heat energy. 

• Players should be able to make use of the three processes of heat transfer to cool vessels. That could be using radiation, with radiator parts in space, or by using the local atmosphere’s convective abilities on a planet, or possibly by using conduction to treat an asteroid as a heat sink.

A cold planet might give you a useful bonus to run your mining drills. A lava planet should give an extra interesting colonial challenge.

 

• Parts exposed to strong solar illumination should heat up.
• Immersion in atmospheres and oceans should heat up or cool down parts.
• Proximity or contact with surface features should heat up or cool down parts

• Positive flux from stellar sources in sunlight.
• Positive or negative fluxes from warm or cold atmospheres, fluid bodies or surfaces.

We’ll apply negative fluxes at times where you might expect useful temperature drops in response to intuitive situations. 

• When your vessel is floating on an icy ocean or flying in a frigid atmosphere.

 

Please listen to what I'm saying for two seconds.

Edited July 21, 2023 by Strawberry

[Spicat]

22 minutes ago, Scarecrow71 said:

Hold the phone.  Are we going to have to deal with heat in colony management?  If so this game is going farther and farther away from building rockets, and I'm not sure I want any part of it any longer.

Actually answered in the second ama (about design):

On 4/20/2023 at 8:24 PM, Dakota said:

Will colonies feature automation gameplay(with-in the colony, so not the delivery route system)? It can look something like: 1) Resource extractor building mines a raw resource, 2) Resource refinery building makes a useable material out of it, 3) Assembly (Acid_Burn9, Discord)

Quote

There's a colony dev blog that I did a long long time ago, which still has things to keep in mind like "KSP is a game about designing cool rockets." Like if a player wants to launch the game and fly a mission to Duna, we don't want the player to have to do 30min of colony overhead to start working towards that goal. We want to make sure automation is implemented to make sure the part of the game that is really important to us, rockets, continues to stay the main gameplay loop.

With further explanation on the philosophy by Dakota's answer:

On 4/20/2023 at 9:15 PM, Dakota said:

It's important to note how much the team is focused on staying true to "KSP = game about rockets." Shana mentioned this a few times, but new additions/features/parts will extend functionality and gameplay in that area - not replace it. As Shana said, if a player wants to get to Duna, they shouldn't have to do 30min of colony overhead before getting started, which is why automation will play a factor in the colonies/exploration milestones.

In my opinion, heat is a cool system that enhances the colony gameplay, I don't think it will be too hard (like the heat in ksp1), just place some radiators and put it in a cold place. I mean ksp2 entire motivation was to be a game about space exploration, thus some colony management is part of it (but staying simple not to transform it like satisfactory).

Source: 

Edited July 21, 2023 by Spicat

[RocketRockington]

27 minutes ago, Nertea said:

I would generally argue that heat in KSP1 has no practical utility outside of reentry and stars, because it vanishes when a vessel isn't focused, and reverts to analytic mode when you're over 1000x warp anyways, which disables conduction and replaces it with an approximation. The system is tuned so that the only time a player needs to interact with it is during reentry and atmospheric flight, which it succeeds very well at (this ignores the core heat system that runs drills and such which is completely different). I'd like to do better than that. 

I'd like you to do better than that too.  The system as outlined though, doesn't.  It does less and worse.  It creates no interesting building considerations - you say stuff like

7 hours ago, Intercept Games said:

to the exotic (fitting a few thousand square meters of radiator to your interstellar vessel)

and yet I can glue those radiators literally anywhere and it won't matter one bit, as long as there are enough of them.

And you could have done that.  Even with a system that only considers very static analysis of a craft's heating - the constraint you're under because you want to minimize per-frame calculation cost, you could have invented a system where any of the following would have given much more interesting craft construction/optimization challenges.

1. Heat pipes between parts have a cost based on true/part-to-part distance, even if they are applied virtually.  To have heat move between a source and a sink, pay for a piping distance.   Piping distance may imply efficiency issues as well.  Lends itself to minimal-cost static analysis, but could come with fun UI and some building consideriations.

2. Heat pipes have an EC cost based on length/flux transfer requirements.  Since your time warp solution also needs to have an EC solution, then you can leverage that for interesting cascade failure problems/solutions - eg setting part operation priorities.  Yay new gameplay!

3.  Craft-as-a-whole analysis and gameplay effects.  Since you think per-part heat simulation is too costly/too much for the player to understand, why not calculate and present tot he player as interesting game effects the overall insolation/heat flux of the whole craft, with a whole-craft heat bucket, and some sort of penalty/cost associated with cooling management if the craft is too hot/too cold for some parts to survive.  

Also, your heat model does through away everything KSP1 was doing well, as you mention, with non-warped reentry and aerodynamics effects, and which are going to feel very strange to KSP1 players.  How are you even handling something like partially occluded parts?  Are you?  Does skin temperature matter or is every part a massive heat sink with perfectly efficient in-part conduction, that would mean almost nothing will actually blow up during reentry?

One of the jobs of a designer is to come up with clever solutions that do more with less.  Not to do much less with more time and budget, and then sell it as much more, that's clearly Nates job. 

23 minutes ago, Scarecrow71 said:

Hold the phone.  Are we going to have to deal with heat in colony management?  If so this game is going farther and farther away from building rockets, and I'm not sure I want any part of it any longer.

It's pretty clear that its not 'management'.  It's 'Have X reactors, glue on Y cooling tower.  Or if there's water, glue on Z cheaper water-radiator'.  I wouldn't worry about having to think about it too much.

Edited July 21, 2023 by RocketRockington

[Pthigrivi]

Much as I love System Heat I think this just the right approach and Im happy to see all the thought going into it and its application for colonies. For the latter are you considering using waste heat for thermal generators or ground-storage thermal batteries (heat in > power out) like parts? Will overall loads respond to day/night cycles?

Edited July 22, 2023 by Pthigrivi

[cocoscacao]

12 hours ago, Scarecrow71 said:

Hold the phone.  Are we going to have to deal with heat in colony management?  If so this game is going farther and farther away from building rockets, and I'm not sure I want any part of it any longer.

Think of it this way, building rocket's became a chore relatively fast. Every rocket needs a purpose, and not much purpose is present in ksp 1. This is a natural progression. Granted, we don't know how base building is gonna be implemented, but it's still a step in the right direction. Some people enjoy taking things to the extremes (build 200kg rocket that can reach Eve), but the rest of us need something more meaningful, other than "record breaking". 

Edited July 22, 2023 by cocoscacao
More thoughts

[regex]

3 hours ago, Nertea said:

 That would be a good goal, I personally don't love its looks though, so it'll be reluctantly

What, you don't like lawn darts?

[Stephensan]

all i got to say is

 

 

[Pthigrivi]

1 minute ago, RocketRockington said:

Well, they had a funds model that you had to work against, if you played career.  So you couldn't just add more boosters indefinitely.  Something that KSP2 is gonna be missing.

Well they're replacing funds with resources which is very likely to increase overall complexity, so there are some trades going on. Unfortunately funds in KSP1 were only really applicable early on as pretty quickly you and a zillion-bazillion funds and they ceased to mean anything. That's a bit different with resources that need to be stored. Given that colonies might have dozens of sources and sinks for heat it makes a lot more sense to keep this system pretty clean and simple. 

[Pthigrivi]

2 hours ago, Nertea said:

  An overall question I'd like to answer is whether you feel like this dev blog was a useful thing for me to put together. Given that my role on the KSP2 team is as a designer, I'm limited in what I can write about, and thought I'd try a long-form design document. If it was informative and interesting to read, I've accomplished my goal, but it is quite a time sink to write long things. 

No its very much appreciated, and gives a lot more clarifying insight into the process and decision making. Love it.
 

4 hours ago, Nertea said:

Hey, that could be a airless planet you're talking about!

Yeah I can think of a ton of applications for the edges of polar craters and hybrid colony systems where solar panels are exposed to near constant sunlight and radiators can be hidden in shade. Combining this kind of engineering with site selection sounds awesome. 

Edited July 22, 2023 by Pthigrivi

[Scarecrow71]

2 hours ago, RocketRockington said:

I wouldn't worry about having to think about it too much.

Ah, but we have to.  This impacts everything to do with colonies:

• Can I build a colony at this location, or do I have to change sites?
• Do I have the requisite parts for heat dissipation?
• Can I build spare parts, or do I have to do missions to bring new ones?
• If I have to bring new parts, will I make it in time?
• Will I have to constantly watch the colony to make sure it doesn't blow up?  And because of that, can I focus on building rockets?

I want to build colonies, but I don't want to have to micro manage  them.

[Pthigrivi]

58 minutes ago, Scarecrow71 said:

Ah, but we have to.  This impacts everything to do with colonies:

• Can I build a colony at this location, or do I have to change sites?
• Do I have the requisite parts for heat dissipation?
• Can I build spare parts, or do I have to do missions to bring new ones?
• If I have to bring new parts, will I make it in time?
• Will I have to constantly watch the colony to make sure it doesn't blow up?  And because of that, can I focus on building rockets?

I want to build colonies, but I don't want to have to micro manage  them.

It may be that at a certain point of expansion you might want or need to set up outposts to gather new materials or take advantage of better access to energy or heat dissipation. That only sounds like a good thing to me. As for parts the idea is if you can gather or deliver resources to a colony you can build components right onsite, so if you’re adding a part that generates heat you can also add parts that dissipate it.  I think what Nertea’s saying is that heat management should be similar to other simple input/output math so all you really have to worry about is having more heat dissipation than heat production. So long as you do you should be able to warp to your hearts content. I believe thats what he means by “cold is good, hot is bad”. 

Edited July 22, 2023 by Pthigrivi

[PDCWolf]

5 hours ago, Nertea said:

  big snip

First off, thank you for answering me and everyone else. I'm not gonna engage much further in the points I originally presented as others have already gone in with even more depth than I originally aimed for. I think the opinions are clear enough. I will however say that the simplifications KSP1 did (big tolerances to hold off spikes) make it still an order of magnitude more complex above the simplifications done to this presented system. How that worked out with the rest of the game (affecting ship design beyond part placement and landing site) you've already been told about.

Having the whole challenge of systems boiling down to "add a part" is not good gameplay, and those are not even my words. As a reminder, we were told that when the AMAs talked against KSP1's science system and how the one in KSP2 will allegedly be much better. Yet, in all of the listed examples, the heat problems are solved exactly that way: add a part, or add more part.

4 hours ago, Strawberry said:

Colonies is where stuff gets interesting. For craft, you can't realistically design around all three forms of heat, your primary thing dictating how much touches the ground isn't thermal in nature, its getting this thing to stay straight up in a variety of conditions. For colonies, you can much more easily design around the methods of thermodynamic transfer. For example, let's say you have a very hot planet close to the sun. You will want to minimize heat transfer as much as possible. So you may make something like this to minimize  thermal conduct.

I did not see any implication in the blog that the surface area of a non-radiator part would play a role and instead any of that would come from an arbitrarily defined number.

1 hour ago, Pthigrivi said:

Well they're replacing funds with resources which is very likely to increase overall complexity

Except here the trend we've seen, even more visible in this system, is to simplify stuff.

[Jaypeg]

@NerteaWill there be parts that require high heat?

[snip]

Edited July 22, 2023 by Snark
Redacted by moderator

[Strawberry]

4 hours ago, Strawberry said:

 

  Reveal hidden contents

• Reentry and atmospheric heating on planets with atmospheres
• Environmental heat sources and sinks (oceans, etc.) that can affect vessels and colonies. 

There are three processes that can do this: convection, conduction and radiation. Convection is a very effective way of dispersing heat, using atmospheric or fluid currents to move heat away from a heat object. Conduction is also efficient and relies on two objects touching – heat will flow from the hot to cold object. Radiation is the least effective way of dispersing heat and relies on the tendency of hot objects to emit photons, which carry away heat energy. 

• Players should be able to make use of the three processes of heat transfer to cool vessels. That could be using radiation, with radiator parts in space, or by using the local atmosphere’s convective abilities on a planet, or possibly by using conduction to treat an asteroid as a heat sink.

A cold planet might give you a useful bonus to run your mining drills. A lava planet should give an extra interesting colonial challenge.

 

• Parts exposed to strong solar illumination should heat up.
• Immersion in atmospheres and oceans should heat up or cool down parts.
• Proximity or contact with surface features should heat up or cool down parts

• Positive flux from stellar sources in sunlight.
• Positive or negative fluxes from warm or cold atmospheres, fluid bodies or surfaces.

We’ll apply negative fluxes at times where you might expect useful temperature drops in response to intuitive situations. 

• When your vessel is floating on an icy ocean or flying in a frigid atmosphere.

 

21 minutes ago, PDCWolf said:

I did not see any implication in the blog that the surface area of a non-radiator part would play a role and instead any of that would come from an arbitrarily defined number.

 

Edited July 22, 2023 by Strawberry

[PDCWolf]

Just now, Strawberry said:

 

Yes, put hot part in cold water, it cools, I get that. Nowhere does it say that the actual size/contact area of the part will affect that beyond an arbitrarily defined number (to make it clear: grab big wide part, submerge only a smidge of a corner in water, the whole part acts like being underwater).

Another fun thing I'm thinking about is exploiting shade by mounting radiators on movable surfaces or just planting a part on top of them to make shade, since the only heat transfer is to the environment, which apparently will be infinitely efficient (and thus no part-environment-part radiation)

 

[asap1]

well no wonder the heat and reentry system is taking a while, its way loveing more complicated than I thought.

[PicoSpace]

First, thank you for answering my questions!

7 hours ago, Nertea said:

I've got some ideas, but the first iteration of this system definitely focuses on cold = good, hot = bad. 

I think for space, cold = bad as well. But maybe "requires repair" bad, or "stops working" bad vs. explosion bad. So the lesser of the two bads, but still quite important IMHO when it comes to planning realistic missions.

Although obviously once the ship is within its ideal temperature range the radiators (etc) would shut off the thermal liquid cycle to avoid over cooling or overheating the ship.

Example Landers:
I googled planet temperatures (don't know if this is accurate or not) but I got 187-288K Kerbin, 160-420K EVE, 150-233K DUNA, 199-277K LAYTHE so a ship in these planets can suffer both extremes; especially cold. So where & when you land and "how long" you can stay on the surface of a planet without expansive radiators is a definetly a cool mission consideration, before you even get into "colonies". Unless you pack a system to manage your thermal issue (too cold or too hot).

PS. I disagree, Kerbals should generate heat, even if its minor... or are you confirming that they are cold blooded? 

pS. Remember that with Apollo 11 the problem for the astronauts wasn’t overheating it was getting cold & sick… then potentially heating up on reentry due to a potentially damaged heatshield. 

7 hours ago, Nertea said:

Your comment about inputs and outputs is exactly right - we look at it as making sure you balanced the I/O. We assume the kerbals build their capsules correctly and that they know the heat exchange piping better than you do! 

But I really know my heat exchangers and thermal fluids...  

5 hours ago, Scarecrow71 said:

Hold the phone.  Are we going to have to deal with heat in colony management?  If so this game is going farther and farther away from building rockets, and I'm not sure I want any part of it any longer.

From the sounds of it, "Colony Management" is basically "big ship on ground" problem, not a "here are a million things you need to deal with" problem. Devs have been pretty clear on that so far, colonies support rockets and expanding space exploration... not the other way around.

Edited July 22, 2023 by PicoSpace

[Periple]

5 hours ago, Nertea said:

An overall question I'd like to answer is whether you feel like this dev blog was a useful thing for me to put together.

It was an extremely interesting read. I don’t think you’re going to make much headway with the people who are determined to hate KSP2 and everybody working on it no matter what, but I think the rest of us really enjoyed it. I certainly did!

In particular I liked the way you describe your thinking: not just what you’re doing, but why you’re doing it and what you want to achieve. I think the proof of the pudding is that re-entry and hypersonic flight still “feel right” while all those new user stories become possible. Also I expect you will have done a lot of iteration on that already!

Edited July 22, 2023 by Periple

[AngryBaer]

10 hours ago, Clayel said:

as someone who used nertea’s heat mods, i can say that it is quite fun to engineer it in

This is a good point though. For anyone who wants a more complex heating sim or more of a challenge in that regard, there will always be mods. It's much better to start with a simplified base you can build on than trying to fit it into an already complex system.

The vanilla KSP2 heating may or may not satisfy everyone but it's likely much easier to modify.