Reverse timewarp

[FITorion]

I don't know if this would be possible... but I think it should... at least in a limited form...

We've all experienced something going wrong and our last quick save being really far back... In fact I just discovered my batteries dead after a long time warp... And yes the problem could be solved already by quick saving often... at least mostly.

But what if instead of having to reload my save from a year of Kerbal time ago... I could just timewarp backwards to a point before my batteries were completely dead?

There would have to be limits. like if you interacted with the craft in such a way as to change its trajectory... or any atmospheric forces on it... I'd like for it to operate across SOI changes though. (Just like regular time warp... but backwards) So the last time you changed things... would be the limit for how far you could go back.

If you didn't have those limits cheating the system to get places you physically couldn't would occur unless you recorded every input or every frame of physics calculations... and that would just be untenable.

I think a limited reverse time warp could be added... if the game can flag and save the last point at which the trajectory got changed.

[xtoro]

I think this could be done by changing the warp speed to a negative value, reversing the rail system. I say it must be doable...

[Tw1]

I think this could be done... but should it?

Timewarp is there so things in game can take a long time without the player needing to wait, but being able to reverse time is a whole other kettle of fish. I can see it being useful as part of a mission planning mode, but in regular flight, I think that's a little too much power.

Perhaps auto quicksaves, or just encouraging people to get in the habit of quicksaveing before doing something important is a better idea.

[arkie87]

I think this could be done by changing the warp speed to a negative value, reversing the rail system. I say it must be doable...

I think you are over simplifying.

Consider this example:

You are in LKO and finish your orbital insertion stage. You go to decouple and then realize you accidentally decoupled your upper stage as well and now you have a bare capsule in LKO. Reversing time warp will just cause you to orbit the planet the wrong way, but will not re-couple your ship...

What is needed to make this useful is a more complicated system that actually reverses what you did in the game (not just the rails). The way it could work is that the game saves ship locations and statuses every second or so, so that time could be reversed. This is, unfortunately, more complicated and also greatly increases the size of savefiles, so i doubt it will be implemented (though it would be great).

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I think this could be done... but should it?

Timewarp is there so things in game can take a long time without the player needing to wait, but being able to reverse time is a whole other kettle of fish. I can see it being useful as part of a mission planning mode, but in regular flight, I think that's a little too much power.

Perhaps auto quicksaves, or just encouraging people to get in the habit of quicksaveing before doing something important is a better idea.

What about auto quicksaves before each stage (i.e. when you press the stage button, the game quicksaves and then activates the new stage).

[Norpo]

I think this could be done... but should it?

It's not a question of if it should be done, it's if it can be done!

We have the technolo- oh, this is the suggestions forum, not the add-on requests forum. Never mind.

Anyways, I agree, it could also be confusing, it could reverse on-rails time, but not "after you crashed into the Mun" time, which could be obscure if people didn't make the connection. And in fact, if you, say, decoupled a stage you wanted to collide into Kerbin, while on a collision course, you could do that, timewarp back to the Apoapsis, and after you burn, continue on your merry way.

Also, i'm not sure what other twilight zone-esque effects would happen.. Still, could make an interesting mod. Kerbal Time-Travel Program.

[KrazyKrl]

Reverse time warp? Oh good lord I can't even imagine how difficult that would be to program.

Not only would you need to save the craft every few game ticks with snapshots; you would also need to run the physics, orbital, and aerodynamic calculations backwards.

On-rails craft shouldn't have a problem, unless you are messing around within their physics range.

Lots of things are easy when warped; you just need to extrapolate and interpolate events. But running events backwards; you would need to somehow make the craft fly forward while moving backwards; while physics forces somehow get reversed.

An easier option; would be to somehow implement a "light" craft saver. Because right now, the quicksave saves a whole KSP universe persistence file. And this saving process is slow, because it needs to save the entire universe as a whole. The all-or-nothing saving requirement is too intensive for short interval quicksaves, like MET -10s, -20s, -30s, -60s, -300s, -600s.

[xtoro]

I think you are over simplifying.

Consider this example:

You are in LKO and finish your orbital insertion stage. You go to decouple and then realize you accidentally decoupled your upper stage as well and now you have a bare capsule in LKO. Reversing time warp will just cause you to orbit the planet the wrong way, but will not re-couple your ship...

What is needed to make this useful is a more complicated system that actually reverses what you did in the game (not just the rails). The way it could work is that the game saves ship locations and statuses every second or so, so that time could be reversed. This is, unfortunately, more complicated and also greatly increases the size of savefiles, so i doubt it will be implemented (though it would be great).

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What about auto quicksaves before each stage (i.e. when you press the stage button, the game quicksaves and then activates the new stage).

Good point.i guess decoupling something could be a point of no return just like if you perform a maneuver. The reason I would want to be able to reverse warp is for simpler things like when I accidentally time warp past my AP/PE or node from finger fumbling. Then I could rewind just enough to stop the warp at the right time.

[arkie87]

Good point.i guess decoupling something could be a point of no return just like if you perform a maneuver. The reason I would want to be able to reverse warp is for simpler things like when I accidentally time warp past my AP/PE or node from finger fumbling. Then I could rewind just enough to stop the warp at the right time.

Even reverse warping on the rails past a SoI transfer is irreversible.

I think the game, by default, should not let you warp past maneuver nodes (it should basically be an alarm like in KAC). This makes sense, both from an intuition perspective since you never would want to warp past a maneuver node, but more importantly, because then you could use maneuver nodes to automatically stop time warp (like a built in KAC). That is an EASY fix and should be stock....

[klgraham1013]

F5 for safety.

[arkie87]

F5 for safety.

f5 doesnt always work.

Case in point: i once f9'd after messing up, not realizing i havent f5'd for hours before i even started the current mission i was on. I lost hours of work. At least, a reverse f9 button would be GREAT!