Pre-launch explosion prevention

[technicalfool]

So I'm sure many people have had a rocket that looks absolutely fine. You go to the launch pad. You wait for physics to load.. then BOOM!

The rocket seems sound, but because the physics goes from 0 to on in the space of a frame, the whole rocket decides to act like a spring, and bits start tearing themselves off, despite being strutted up to the eyeballs.

So, how about making it so that gravity is at 0 the moment physics starts, and the spacebar is disabled. Over the course of maybe a second, the gravity could gradually take effect, giving various rocket parts the chance to settle, rather than bounce. The spacebar can come on when gravity has reached 1x normal strength. Of course, this wouldn't stop a poor rocket design from falling to bits, but it may stop the need for huge amounts of struts to keep an otherwise steady rocket from unplanned disassembly before it even gets off the floor.

It could also stop some aircraft from splashing all over the runway due to having to drop a few feet onto the floor when physics starts.

Yay, nay, or does anybody have a better suggestion?

[Outlander4]

I think inability to handle Kerbin's gravity when standing at the launchpad will be a sure reason for unplanned rocket disassembly when under acceleration.

[technicalfool]

I think inability to handle Kerbin's gravity when standing at the launchpad will be a sure reason for unplanned rocket disassembly when under acceleration.

Not necessarily!

I have had a couple of different designs which, most of the time, will stay together on the launch pad. Once launched, they stay together all the way up. However, there might be a 30% chance that when physics enables, and that sag happens, the whole rocket will bounce on its launch stabilizers, and bits will come off.

Having the gravity gradually fade on rather than suddenly be there, would mean that a sturdy-but-large rocket design has more chance of staying in one piece, without having to spam struts. There's basically no sudden shock to the structure, which is what can cause pieces to detach.

The same goes for aircraft. I'm sure there are many people who have held their breath as the aircraft gets spawned above the runway, and drops like a stone the short distance to the floor. Having gravity fade on over a second or so would, I'm pretty sure, help with that too.

[shand]

The problem isnt the gravity of the situation per se. the problem is interactions between parts, must unplanned launchpad disassembly is due to part on part interaction. in other words physics is the problem.

unity doesn't allow physics to be "slightly on" its an all or nothing response. a gravity tweak may reduce explosions a tad, but thats really masking issues. a "better" response perhaps would be to enable unbreakable joints and parts until the spacebar is hit - but again, should the game be making up for design errors on your part? if your ship cant be held by just 2 clamps, why havent you put another higher up the rocket?

[technicalfool]

The problem isnt the gravity of the situation per se. the problem is interactions between parts, must unplanned launchpad disassembly is due to part on part interaction. in other words physics is the problem.

unity doesn't allow physics to be "slightly on" its an all or nothing response. a gravity tweak may reduce explosions a tad, but thats really masking issues. a "better" response perhaps would be to enable unbreakable joints and parts until the spacebar is hit - but again, should the game be making up for design errors on your part? if your ship cant be held by just 2 clamps, why havent you put another higher up the rocket?

Thing is, I'm pretty sure you'll have noticed a visible "bounce" on some rocket designs, when the physics switches on. That kind of force could be putting the rocket parts under greater stress than any launch the stack will be put through (well, unless Jeb's piloting it, of course). If it's a choice of having the gravity fade-on to at least pretend that the rocket was slowly hoisted into position on a crane or something, rather than spamming an already-straining game engine with yet more parts, I'd very much rather have the gravity fade on. This isn't about the entire physics engine somehow fading into existance - I know that's not possible. Just the gravity force. If it fades on, there's less chance of a bounce, and less chance of an otherwise sturdy-enough rocket stack flexing about like it's made of bedsprings and having bits come off.

I'm pretty sure if you took a NASA-designed rocket stack, hoisted it three feet up and dropped it onto the launch pad, there would be damage. Same thing, really. And, as already stated, it could very well help with an aircraft's tendency to be spawned just that little bit above the level of the runway.

Besides, even if the rocket wouldn't make it up in one piece and is only hanging on by a thread anyway, failures at t+10 seconds are always more awesome than failures at t-10 seconds, wouldn't you say?

[shand]

hehe agreed with that last bit.

perhaps best would be the ability to turn on gravity in the VAB (with unbreakables and without the ability to edit while its on)? that way when it spawns on the launchpad its already at full gravity.

thinking about your suggestion, what would it do to other loaded parts if the gravity changed wildly (instantaneously going to 0 for example), gravity cant be applied to one craft different to another (as far as i know). try having a rover near the launchpad and hacking gravity in your new vessel. the rover goes flying (or at least up a bit) and then crashes into the ground. so that really isn't a viable solution.

[technicalfool]

hehe agreed with that last bit.

perhaps best would be the ability to turn on gravity in the VAB (with unbreakables and without the ability to edit while its on)? that way when it spawns on the launchpad its already at full gravity.

thinking about your suggestion, what would it do to other loaded parts if the gravity changed wildly (instantaneously going to 0 for example), gravity cant be applied to one craft different to another (as far as i know). try having a rover near the launchpad and hacking gravity in your new vessel. the rover goes flying (or at least up a bit) and then crashes into the ground. so that really isn't a viable solution.

Well, I'm not a Squad developer, I don't know how they've done the physics in the game. However, I'm sure it should be possible to have objects to which gravity is not applied. The same as how some objects (I think struts for instance) don't have any collision detection. Stuff can go straight through them without causing damage. It may well be possible to fade gravity on, but only for the new objects that have appeared on the launch pad. Once gravity has faded to 1x normal for them, then whatever "part_is_new=true" or (better) "stack_is_new=true" flag is used can be removed, and any related parts are affected by the global gravity value as normal. Something like that should be a minimal extra expenditure of CPU resources, and means you don't have to strut-spam anything over a few hundred parts just to get it to stay together on the launch pad, when it would otherwise be strong enough to survive to orbit without such a high strut count.

If it's not going to take too much time to test it, I'd love to see the results, anyway. As much for aircraft as for rockets.

[lajoswinkler]

Just use those red holders and put them close to the bottom of the rocket, holding the outmost parts. Works for me.

And use strategically placed struts, to carry the weight appropriatelly.