FreeOrion

This thread is to discuss Ship Engines. Issues include:

* How should engines be represented in ship design?
** Engine part(s) put into slot(s)
*** If engines are slotted, should it be possible to put in more than one engine per ship?
** Non-slotted pick-one-from-list engine types

* Should there be separate in-system and interstellar engine characteristics?
** Engines could have two ratings, one for in- and one for inter-system
*** If there is more than one engine in a ship, do the properties stack (so you can add two engines to go faster) or does the best property for the situation get used (eg. in system vs. interstellar)?
** Separate in-system and interstellar engines could need to be added

If there's something important I've missed or something basic that I've assumed but shouldn't have, please point it out.

Issues of whether there should be ships without in-system engines or without interstellar engines can be discussed later. This thread should be about how engines work in a design, and as much about how they function as is necessary to decide how they work in a design.

Thanks.

Regardless of whether a list or slot system is used, egines should be able to be placed on a ship in any number, on any side of the ship, if you even want engines. It should all depend on the space available for engines, eg if you can fit them, you could have two engines at the rear, and one on the left and one on the right. This of course should only be possible if there is a valid gameplay effect to having engines on the sides and front of your ship. Front engines help slow the ship, maybe side engines allow directional movment without turning. Of course the player would still tell the ship to move from A to B, but the ship would manuever and travel there based on the engines it has.


I think that there should be different engines with different characteristics. Not just faster and faster engines, but a variety of attributes, as well as speed to consider when choosing engines for a ship. There should definately be system only engines (sublight/impulse) and interstellar engines (warp/hyperspace/jump/ftl), it's a matter of technology and price. And they would be used in the appropriate setting (ie warp only between systems and impulse only in combat). There should be other engine types and travel types as well (solar sail, stargate, carrier, tugs) for variety as I believe a ship is mostly defined by its engines.

Here is a relevant thread.
Spacecraft Propulsion

I really believe we can have some interesting engines types and hope we aim for something more than faster and faster engines. For now, in space combat, we won't really need to concentrate on interstellar engines so much, so it depends on how much we are willing to concentrate on now.

Nice to see some new threads


I agree with everything, except strafing, side engines should help turn the ship rather than move without turning. also I would like to see a slot system not a list system.

One thing what happens if you have 5 engines on the starboard and no other, dose the starboard become the rear or will it the ship be very good at turning but very slow?

My vote is for it turning fast but travelling very slow, if this is made clear to players then it gives players the option of fast turning ships that are slow should they want them.


more than that, there needs to be enough characteristics to allow engines to differentiate in more than just price and speed. I can't really think of how to do that for interstellar but for combat I would have the following values per engine:

Acceleration
Maximum speed
angle efficiency*
heat generation**

* a really bad name I know, what it means is how much of an engines power can be dedicated to turning, if you have an angle efficiency of 50% an a maximum speed of 10, then you could have 10 speed points moving forward, or 5 moving forward and 5 turning, or anything between that. Similarly a engine on the side with an angle efficiency of 50% could have 10 points turning clockwise (or anti if its on the other side), or 5 points accelerating/decelerating and 5 points turning clockwise.

** how much heat the engine generates in addition to that removed by the cooling systems, if this is greater than 0 you get heat buildup and the engines must be perodcally shut down to prevent overheating.

Acceleration and maximum speed could be relative to the mass of the ship in place, if this is the case then when designing the ship you should see a different value for the same engine when building different sized ships, prevents the need for mental maths.



Its hard to say without balance testing by my instincts say:
Out of system: a diminishing marginal returns system, the first engine gives 100%, the next two give 50%, the next 4 give 25% the next 8... With the best engines (best of out of system travel) getting the higher %s.

For in system I'd have them stack up, but every engine is treated individually. so if you're traveling forward and you have two engines, one with 5 acceleration and 10 max speed, and one with 2 acceleration and 20 max speed then after 1 "tick" you're on 7 speed, then 14, 16 ... 30

Be aware that that's instinct talking, I wouldn't put too much behind it. And I'm a bit nervous it may be too complicated with many unique engines on each side of the ship, and an AI working out the optimum use for each engine. A simpler method is that you chose that this ship uses Ion Engines, then you can only add ion engines, since they're all identical the game could abstract 3 ion engines (acceleration 1, max speed 10) into one engine (acceleration 3, max speed 30)


I can see arguments both ways:
It leads to extra choices in design, focusing on reaching a system fast, or being more effective when you get there.
But it leads to a home field advantage, as defence ships can be built for in system travel only (i know you said we're not talking about the prospect of no-interstellar engines yet but just using a single, cheap, small level 1 interstellar when you're at tech level 10 or something is as good as none for this purpose).



Well we should decide if ships automatically slow down without their engines or if they can only slow down by thrusting in the opposite direction.

Didn't we already decide on a slotted design for construction?
I don't see the need to hand place all the manuvering thrusters. I find it sufficient to place engines in any number of internal slots. The engineers are competant to channel that power. More engines = more accleration/manuverability.

Allowing the player to specify speed and manuverability separately seems uninteresting and possibly quite annoying. How do you control a really fast ship that can't manuver?


It seems simplest and most interesting to me to keep the Starlane and in-system engines as totally separate entities. This allows ships to speciallize in a way that i think is worth-while quick starlane travel vs in-system manuverability. Or you could break the bank and give it both.

It may seem a bit confusing at first to need 2 engines in most/all of your ships, but the warp/impuse dicotomy is quite familiar, and more importantly it will be much simpler to keep the engine types straight in your mind. Let's suppose there are 10 levels of speed between fastest and slowest for both types of travel. With separate Starlane and System engines, 20 individual engines covers the same gamut of possibilites that 100 engines which each had a Starlane and system value could. Admittedly many of these possibilites would be little used, but still having separate items which control totally separate funtions is simpler to remember.


The player will be controlling a fleet of ships in nearly real time. Ships should be easy to control. Allowing the player to configure ships that are annoyingly hard to direct (i.e. has no brakes) in order to squeeze on more firepower is not a situation we should encourage. The challenge of battle isn't supposed to be some arcade-like test, where much of the though is put towards finagling the ships to do go where you want them.

_________________
—• Read this First before posting Game Design Ideas!
—• Design Philosophy
—•— My Ideas, Organized —•— Get an Avatar —•— Acronyms —•—

Actually, there is quite a bit of strategy. It would be simple either way, "player clicks X, ship attempts to get there". Depending on player engine setup, a ship may go straight there. If as you said, there is a lack of manuevering thrusters, then the ship may take a longer radius in turning around to get to the destination. If the ship is really bad at moving, then that is bad ship design, and all the weapons are not so useful, if you don't have decent engine design.

For the majority of parts, but it was noted that some special case design decisions might be non slotted. Armour was the paraticular example given of (potentially) such a decision, but engines seemed sufficiently different from weapons to be worth discussing the option for as well.


I have a convoluted but serious concern about having separate engines in this way...

Despite utilae's preference to the contrary, I think all ships should have interstellar engines. This is because if we have ships without insterstellar engines, "system ships" to some, then we'll have to treat these ships differently in the UI, as putting them into a fleet will mean the fleet can't move, which could be confusing or frustrating for players - significantly more so than similar issue with ships unable to move (quickly) due to lack of fuel.

So, if we have entirely separate engine parts for in-system and interstellar travel, if the player wants to "cheat" and make a ship with a really cheap interstellar engine and a very good in-system engine, they can essentially bypass the every-ship-has-an-interstellar-engine restriction. I don't think this is something we should be encouraging.

So, if instead of seprate interstellar and in-system engines, we had single engines to do both, where these engines had separate ratings in both, we could set up the available engines so that if you want to make a fast in-system ship, you generally have to put in a fast interstellar engine as well. There would be some variety in the available engines, so that some are better at in-system or interstellar, probabaly erring on the side of better interstellar, to keep things interesting.


In particular: Unless there's a compelling reason to do otherwise, we'll probably never have ships that take more than one combat round to accelerate / decellerate to/from full speed and full stop. Worrying about continuous acceleration rather than a fixed max speed is unnecessary and counterproductive realism.

I am undecided about the value of having ships with no SL drives, however assuming that's not an option i still think it's best to have separate engines for the reasons outline above. Your concerns can be addressed without having only dual purpose engines, thus:
* All ships have 2 engine slots, which come default with the latest warp and impulse drives.
* The player may replace these engines with lesser tech-level version.
* For increased power, the player may use additional internal slots for engines.
* But the two special warp and impulse engine slots cannot be used for anything other than their respective type of engine.



I don't see how that's "cheating" or undesirable.

The only reason you've provided for a "every-ship-has-an-interstellar-engine restriction" is a UI annoyance in forming fleets. That annoyance is not present when every ship does indeed have an interstellar drive, even if that drive is slow. So there's no reason to try to stop the player from bypassing this restriction as long as the UI annoyance is avoided.

Few ships will be good at everything. While i don't favor allowing the player to build totally useless ships, i wouldn't qualify ships with slow intersteller drives "useless".
Irrespective of the design decisions here, the player will have to deal with fleets made up of ships of varing interstellar speeds. A simple UI device to sort ships by Interstellar speed is the answer here.



Making the player worry about how hot his engines are seems very out of place in FO Combat. Meters should not be attached to ships without a very compelling reason. It is going to be a challenge making the current info easily accessable to the player during battle without adding more.
Combat is not turn based. You have to control many ships, quickly.

_________________
—• Read this First before posting Game Design Ideas!
—• Design Philosophy
—•— My Ideas, Organized —•— Get an Avatar —•— Acronyms —•—

Actually if you force players to have interstellar drives when they want system ships, they'll pick the smallest, slowest, cheepst driver they can. Won't there be an annoyance if they find they've sent that ship with the fleet and everyone is slowing down to match it? Perhaps solving the UI issue is a better solution than trying to artificially remove the problem?


Slow drives arn't useless, I agree. But I'm not too worried about the prospect of it being possible to build totally useless ships, just providing you have to be really stupid or deliberately trying to do it.

Nice idea, sorting by fuel and dammage both sound usefull too.

At this point I feel the need to point out that since there are no FTL engines then we could conceivably have the same engines for both sorts of travel.

hmm... How complicated do we want fuel usage to be? It'd be simple if we make it so you can only have one engine system per ship. Maybe have optional parts for increasing speed, but the engine system itself, while not necessarily a single part, would function as a single unit.

_________________
Computer programming is fun.

We should avoid details of design mechanics such as specialized slots in this discussion. That multiple engines of the same type can be added is a more general point though, so was included in the original post.

Also a bit off topic, but: it may be a faulty assumption that the player would always (or typically) replace an expensive powerful part with a cheaper "lesser tech-level version". Rather, other part options may be just as advanced, but advanced in a different way, such as to reduce cost or build time or fuel consumption, rather than speed, etc.

Regardless of those issues, I'm not really convinced about the need or benefit to having separates for interstellar and in-system travel. Are there any interesting or important strategies that would arise to warrant the extra complexity?


If a ship is very slow, it could be just as annoying as if it was totally immobile if it gets grouped with some fast ships... or possibly more so, if you accidentally send the fleet along a starlane and have to wait several turns before you can turn it about...


Indeed, the problem isn't entirely avoidable, but I'd like to avoid it happening inadvertently as much as possible.


Right... and if interstellar and in-system drives are separate, picking the cheapest possible interstellar drive (and not using it) becomes a lot easier, as there's no corresponding tradeoff in in-system performance.

I suppose we shouldn't ignore other potential tradeoffs though... Old / cheap instersellar drives may also be non-stealthy or prone to being damaged in battle.

OK, since there hasn't been any further input on this thread, I think I'll tentatively suggest / decide on a flexible system, and invite comment on it:

* Engines are regular ship parts that are placed in standard slots. (ie. no engine-only special slots)
* Ship designs can have multiple engines. The bonuses / penalties of the multiple engines stack
* Engines have two basic ratings: Interstellar and In-System
** The specific units of these measures, and how they relate to actual speed of ships, is to-be-determined. It might be a "Power" rating, where Speed = Power / Mass, or it might be a simple "Speed" rating.
** A particular engine's two ratings are independent. There might be an engine that provides no interstellar benefit, or a mixed engine that benefits both. These can be balanced as needed.
* Ship designs need to have at least one engine, and at least some to-be-determined minimum rating in both categories to be a valid design.

That is too flexible. Might be hard to balance.
IMHO only one engine per ship should be allowed, but engines should be customizable so it is possible to make small adjustments to their cost, space required and speed.

_________________
In Soviet Russia, forum posts YOU!!

True, but why not let them have no interstellar engine? If the UI puts these system ships in a different window then you can't accidentally mix the system ships with you're normal ships. If you do force people to use old engines then that just means you can mix and match the ships that should and shouldn't move. This anoys players since they have to reverse when they arrive and because all ships are matching the speed of the slow system ships.


Another reason not to force players to put an interstellar engine, they shouldn't have to worry about trade offs for an engine they never ever plan to use.


Just a few comments

• speed = power/mass
• In balancing consider the possibility of makeing engines not stack linerly. Instead it may be 100 power for the 1st engine, then 50 for the next 2, then 25 for the next 5. And so on
• Minimum of one system engine, interstella engines are optional

Contrarily, IMHO the simplest way to guarantee that a ship has at least one engine is to define an engine-only slot. When any new design is initiated that slot is filled with an engine. At no point can that slot be filled with a non-engine component, so there's no need for a "validity check" and the accompanying error messages for an invalid design. If an action is going to be illegal, it's less annoying if the computer simply doesn't let you do it, than getting an error message when the ship is done.

Of course, if i make my point that Starlane and in-system drives should be distinct components, then each should have it's own devoted slot.


Sure. But any engine components beyond the first non-removeable component must be placed in an internal slot.


Conceptually, i still think it's a bad idea to lump these two functions together into a single component. Movement in-battle and via Starlanes are completely different game concepts, that follow completely different rules. One requires fuel and has a limited range, the other has no such units. It will simply muddle up how the game to lump two very different functions into a single unit. Anything you might say about the statistics of a dual-drive engine would only apply to one of it's functions. Declaring them a single item is arbitrary, and somewhat confusing. It's better to keep the concepts of Starlane travel and in-system maneuvering distinct in the player's mind.

It is very much like (though not so blatant) lumping any weapons together into a single component to instead of simply filling a slot with "lasers" or "missiles" the player would be presented with a bunch of "weapons" components which have different ratings in the various weapons types.

I really don't see a reason in this thread why it's a good thing to lump Starlane travel and in-system maneuvering into a single component— other than your concern that players will equip their ships with lousy Starlane drives and then get annoyed that the fleets move slow. I don't share that concern, (any ship will probably be deficient in some way) but if i did i'd try to deal with it another way, such as rigging the tech tree so that old components can be removed as options once they no longer have any advantage over newer components.


I don't understand the second part of requirement. I would hope any "engine" provided by the game should be acceptable without the player concerning himself with a "minimal rating."

After consideration, i think that all ships should have some sort of Starlane drive. Otherwise the "system ships" would be stuck in systems with shipyards, which makes them mostly pointless. Even if the scheme for making carrier ships which can carry ships larger than fighters goes through, (which seems unlikely at this point) it's IMHO not much fun to have to load such ships up on transporters to deploy them at a destination.



The design of this game is about avoiding "small adjustments" (i.e. micromanagement) and only presenting the player with significant choices.

_________________
—• Read this First before posting Game Design Ideas!
—• Design Philosophy
—•— My Ideas, Organized —•— Get an Avatar —•— Acronyms —•—

I meant "small adjustments" as compared to doubling of speed caused by adding another engine. Even small changes to speed can be significant.

What is the purpose of allowing multiple engines per ship?

_________________
In Soviet Russia, forum posts YOU!!