Rewind?

[Superluminaut]

The pause button is very cool.

It got me thinking...

Rewind?

[Bej Kerman]

I was thinking slow-mo. In fact, KSP 2 lets you configure how fast each timestep goes...

Once you do this, you can fiddle with it a bit. If you change the timestep a bit, you can get the game to run in slow motion. Unfortunately, sometimes timestep 1 puts you at 1x rather than 0.25x and timestep 3 which is now 1x behaves as 4x would, occasionally putting your vessel on rails if you cease acceleration when on a surface or outside the atmosphere, making it difficult to use the feature in a natural manner - above all, the default timestep is 1 but the game forces 1x time acceleration on load so going to timestep 2 slows the game to 0.5x and going back again puts you at 0.25x, and this also seems to break staging if you're in slow mo. I hope @Nate Simpson et al properly integrate all this into the game, and more importantly expand the timewarp applet to support customisation and specific timewarp levels, because it's a shame to see that the foundation for a stock BetterTimeWarp is there as well as the ability to use any number of timescales like Universe Sandbox, but unused in favour of KSP 1's rigid "You have 8 timescales to choose from, take it or leave it" design.

[viccie211]

Rewind would be a cool idea, but I'm trying to get my head wrapped around how it would work. Only on rails rewind would not be much of a problem I think, "just" run the on rails orbits in reverse, but in physics warp it would be way more difficult I think, because all the physics simulation and controls would have to work in reverse too, generally that should not be a problem, but maybe some shortcuts in the programming  of the simulation are built on the expectation that time runs in one direction.

[sumeee]

I don't think rewind will be possible because the physics engine used is not fully deterministic, so even if you run the time in reverse you will turn out in some other state that you begin with.

I'm not saying that KSP2 implementation is bad, I think that are no fully deterministic real time physics engines.

[Vl3d]

Related:

 

[Maria Sirona]

14 hours ago, Superluminaut said:

Rewind?

Ever heard about quicksaves?

[Tazooka]

36 minutes ago, Maria Sirona said:

Ever heard about quicksaves?

True, but in the current build they often bork your ship

[Superluminaut]

On 3/6/2023 at 3:16 AM, sumeee said:

I don't think rewind will be possible because the physics engine used is not fully deterministic, so even if you run the time in reverse you will turn out in some other state that you begin with.

I'm not saying that KSP2 implementation is bad, I think that are no fully deterministic real time physics engines.

I thought about this a bit and then realized you don't have to run physics.

As far as I know only the active craft --or crafts within x radius of active craft-- runs physics. Everything else is on rails.

It would not be very intensive to record position, attitude, velocity vector, and part states (throttle, solar deployed, etc) for the crafts under physics.

When you hit rewind you would simply step back through the recording until you hit play and then physics reloads.

Edited March 7, 2023 by Superluminaut

[Maria Sirona]

22 hours ago, Tazooka said:

True, but in the current build they often bork your ship

Ever heard about patches? 

Also, i actuakky thinl that a rewind audiovisual effect when quickloading would be cool- but probably impossible to implement. Let's not bother the devs with this.

[darthgently]

19 hours ago, Superluminaut said:

I thought about this a bit and then realized you don't have to run physics.

As far as I know only the active craft --or crafts within x radius of active craft-- runs physics. Everything else is on rails.

It would not be very intensive to record position, attitude and part states (throttle, solar deployed, etc) for the crafts under physics.

When you hit rewind you would simply step back through the recording until you hit play and then physics reloads.

The code could lerp between fewer recorded positions easily enough also