[0.90] [Patch] SlowChutes - make chutes gentler. 0.02 2014-12-17. Superseded by TweakableParachutes.

[Kerbas_ad_astra]

This patch has been superseded by the TweakableParachutes module in toadicus's TweakableEverything. It lets you do the same thing as this patch did, but better because you can adjust it for each parachute.

That said, I'm leaving this up here because it may be useful as versions change (or if you want this function in older versions that predate TweakableParachutes) -- as long as you have a 2.x version of Module Manager, this patch will work. Do not use both at the same time! The deployment-time multipliers will stack, resulting in parachutes which take a stupendously and dangerously long time to open! I figured this out the hard way during testing, when I forgot to remove my patch before testing TweakableParachutes for the first time. I should have noticed the unusually low deployment-speed indicator in the editor, but it didn't sink in until I crashed the test vehicle...

Original post

Are your Kerbals tired of back-breaking G-forces when parachutes fully deploy?

OUCH! According to Kerbal Engineer, the peak G-load experienced by a Kerbal 2 command capsule upon chute deployment is 19.4 G's (the needle has a finite speed, so I'm assuming the 19 G's happened too fast for the needle to make it all the way to the top of the gauge). In mods which track G-force damage, or when landing large constructs, this kind of force could be deadly.

There's a better way! Presenting SlowChutes! The lightweight, openly-licensed solution for your chute-deployment-slowing needs!

Ahhh, much better. By reducing chute deployment speed by a factor of 100, the peak G-force is reduced to a much more manageable 3.7 G's.

This reduced deployment speed comes at a cost -- the parachute needs more altitude than before to fully open and bring the vehicle to its final speed. The "deployAltitude*=2" line will do that for all newly-constructed vessels, but vessels made or launched before installing SlowChutes (including stock vessels) will still have the default deployment altitude of 500m. 1000m seems to do the trick, but be sure to check that it's been properly set before landing.

Installation

First, make sure you have the appropriate version of Module Manager installed.

Next, create a text file in your GameData directory with the following text (I would suggest a descriptive title like "SlowChutes.cfg"):

@PART
[*]:HAS[@MODULE[ModuleParachute]]:FINAL
{
    @MODULE[ModuleParachute]
    {
        @deployAltitude *= 2
        @deploymentSpeed /= 100
    }
}

Changelog

2014 Dec 16 -- First release.
2014 Dec 17 -- Added ":FINAL" to better cooperate with other mods (e.g. SDHI).

License

This patch is licensed under the MIT License.

Copyright © 2014, Kerbas_ad_astra

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Gaps and known issues

I have only tested this patch with small things (capsules) landing on Kerbin. It should work well for bigger things and on other bodies, but who knows? Please let me know what you find.

Also, it seems that the deployment height is only adjusted for vessels which are built or edited after installing this patch -- otherwise, you'll have to tweak it on the launch pad. Keep an eye on this, for reasons stated above.

Roadmap

I had wanted to make chute deployment speed a tweakable parameter (so that I could have gentle main chutes and backup emergency chutes which snap open), but toadicus beat me to the punch (thanks to hazens1 for suggesting it to him, and thanks to toadicus for making it happen). TweakableParachutes, debuting in TweakableEverything 1.7, does what I had hoped to do, so this is the end of the road for SlowChutes.

Edited December 31, 2014 by Kerbas_ad_astra
TweakableParachutes has been released.

[superm18]

This is VERY handy when using DRE

Thanks a bunch

[Kerbas_ad_astra]

Glad you like it, superm18. I figured DRE or keepfit wouldn't like those G-forces.

Once I've got a station up, I'll see how it comes down with stock chutes vs. my config. Either way, it should be spectacular!

[Kowgan]

That's a nice feature! Am I reading it right? Does that mean the chutes will slowly decrease the vessel speed, instead of a drastic speed change?

Thanks for your effort!

[Liquid5n0w]

Great mod!

Why not add it to CKAN and get the AVC version file in there so people can be kept up to date?

[NBZ]

Great. May I recommend SafeChute? You guys should consider merging!

[Kowgan]

Again, still a great mod, but I just found a flaw: Even on low speeds, the chute still takes 100x the original time to decrease the current speed. That means, if I need to abort a launch (using the Launch Escape System, for example), the parachutes will be useless in such a low altitude. They will take too long to decrease my already-low speed, and the vessel will crash to the ground.

I'm not sure what kind of math would have to be done there in order to fix that, though. Maybe you wanna calc what's the gravity speed change in the low atmosphere (9.8m/s?) and set that as the DeploymentSpeed, instead of "/=100"? I don't really know.

I guess the realistic parachute works something like this:

- The parachute is always trying to reach the X speed.

- The bigger the difference between X and your current speed is, the slower the parachute will decrease your speed.

Does it make sense?

-edit-

Scratch it, it doesn't make sense.

Maybe the scratched item could be replaced by this:

- Current speed never increases, unless any of the following conditions meet:

---> A major force is applied in the vessel (engines, etc.)

---> current speed < X

- X is a float number, defined by the vessel mass, and the current gravity force applied into it.

I wouldn't know how to apply that in the game, though.

Edited December 17, 2014 by Kowgan

[LitaAlto]

I'm not sure what kind of math would have to be done there in order to fix that, though. Maybe you wanna calc what's the gravity speed change in the low atmosphere (9.8m/s?) and set that as the DeploymentSpeed, instead of "/=100"? I don't really know.

I realize you were going for realism, but maybe it'd be enough to pick an arbitrary speed where chute deployment, in general cases, doesn't cause excessive G-forces, and then have a ratio of the current speed to that arbitrary speed.

For example, if 250 m/s seems reasonable, just divide the current speed by 250. If it's greater than 1, deploy slower. (And maybe if you invert the ratio, you could use that as a multiplier for determining the deployment speed.) If it's less than 1, deploy as stock.

That may not be 100% realistic, but should be enough for general gameplay.

[Kerbas_ad_astra]

That's a nice feature! Am I reading it right? Does that mean the chutes will slowly decrease the vessel speed, instead of a drastic speed change?

Thanks for your effort!

That's it exactly. The "effort" was mostly in making that OP and getting those screenshots -- I wanted my chutes to open slower (and didn't care much for the additional stuff that RealChutes has), so I made a quick Module Manager patch to do that (and did some testing to find that 100x was the right slowdown, and that I needed to increase the opening altitude). Since I figured RealChutes might be some time in updating to the beta, I went ahead and put my patch out here for general use.

Great mod!

Why not add it to CKAN and get the AVC version file in there so people can be kept up to date?

Maybe in a few days -- I've got a GitHub account, but still need to learn some of the intricacies of repos and such. The "mod" is so simple as it is that there's not much point just yet. If I make a tweakable-chutes kind of mod, it will have that stuff for sure.

Great. May I recommend SafeChute? You guys should consider merging!

I'm with hab136 on this; our mods don't really do the same thing -- they're both intended to prevent parachute deployment from destroying vessels, but they do it in different ways.

Regarding his comment about RealChute compatibility, I haven't tried using them together (again, not interested in the other stuff RealChutes does), and if you are using RealChutes, you're getting gentler deployment anyway. I could put a ":FINAL" at the header of the patch (and thought about doing so), so that it will only patch parts if there are any ModuleParachutes left after any other mods run, but I didn't think it would be necessary as I'm pretty sure RealChutes strips out all parachute modules and replaces them with its own thing, so it wouldn't matter if this patch ran before RealChutes or after.

That said, I see that SDHI defaults to assume that RealChutes is present, and only replaces them with stock chutes if it's absent (which seems backwards to me, but whatever -- I'm sure sumghai did this for a reason, maybe I'll ask), so I guess it would be better if this patch ran during :FINAL. Let me just make that change real quick...and done!

Again, still a great mod, but I just found a flaw: Even on low speeds, the chute still takes 100x the original time to decrease the current speed. That means, if I need to abort a launch (using the Launch Escape System, for example), the parachutes will be useless in such a low altitude. They will take too long to decrease my already-low speed, and the vessel will crash to the ground.

I'm not sure what kind of math would have to be done there in order to fix that, though.

That's why I want to eventually make this a tweakable parameter, so you can have your emergency chutes (bound to the abort group instead of staging, I suppose) which snap open when you need something to stop now!, and then have gentle main chutes for normal use.

Above all else, I want to keep this simple -- I'm just tired of wincing in sympathy when my crew gets subjected to 20 G's when the chute snaps open. A context-sensitive "AdaptiveChutes" mod would be cool (anyone who wants to make a mod that does that, feel free to use the name!), but I'm sure everyone has different ideas about when they want chutes to snap open vs. ease open, and I don't feel like making a mod that's forced to read minds.

Before the tweakable option exists, non-parachute-based options for emergency deceleration include airbags from USI Survivability Pack (I've successfully used them on Mun probes) and retro-rockets from XT Landertrons.

Edited December 17, 2014 by Kerbas_ad_astra
Change made.

[Kowgan]

That's why I want to eventually make this a tweakable parameter, so you can have your emergency chutes (bound to the abort group instead of staging, I suppose) which snap open when you need something to stop now!, and then have gentle main chutes for normal use.

You, sir, are a genius! And I totally agree with you, the simpler, the better! And I don't want you to take me wrong; no matter how simple was your effort to give life to this mod, it's still something unique and you came here and did this. It's a respectful effort, yes. Thank you for that, again. The mod is great!

[Kerbas_ad_astra]

Something else that occurred to me: I could (instead of a patch or a tweakable-chutes mod) make a few parts which are just slow-opening versions of the stock chutes. Same models, recolored textures (I can probably manage that much modeling work with my current level of experience), deployment speed set to 0.01, deployment altitude at 1000 m.

[mjak]

Hey guys,

I'm running NEAR, and would like to slow the stock chute speeds down to a reasonable level. Unfortunately, the default settings seem to be a but too slow as i'm easily above 100m/s when I arrive on the ground. I've tried a few other changes but I can't seem to find a happy medium (I'm aiming for below 5G's on landing).

[stupid_chris]

That's it exactly. The "effort" was mostly in making that OP and getting those screenshots -- I wanted my chutes to open slower (and didn't care much for the additional stuff that RealChutes has), so I made a quick Module Manager patch to do that (and did some testing to find that 100x was the right slowdown, and that I needed to increase the opening altitude). Since I figured RealChutes might be some time in updating to the beta, I went ahead and put my patch out here for general use.

RealChute has been updated for a while now. The other good thing about RealChute is that if you don't want the extra fluff, you just.. don't use the extra fluff?

Regarding his comment about RealChute compatibility, I haven't tried using them together (again, not interested in the other stuff RealChutes does), and if you are using RealChutes, you're getting gentler deployment anyway. I could put a ":FINAL" at the header of the patch (and thought about doing so), so that it will only patch parts if there are any ModuleParachutes left after any other mods run, but I didn't think it would be necessary as I'm pretty sure RealChutes strips out all parachute modules and replaces them with its own thing, so it wouldn't matter if this patch ran before RealChutes or after.

There are absolutely no compatibility problems with this. All you do is modify values of ModuleParachute. If I go first, I delete all the ModuleParachute nodes, so your patch targets nothing. If you go first, I pass after, delete the ModuleParachute node and slap the RealChuteModule nodes. If somehow there happens to be parts with ModuleParachue and some with RealChuteModule, well, both work.

That said, I see that SDHI defaults to assume that RealChutes is present, and only replaces them with stock chutes if it's absent (which seems backwards to me, but whatever -- I'm sure sumghai did this for a reason, maybe I'll ask), so I guess it would be better if this patch ran during :FINAL. Let me just make that change real quick...and done!

Because RealChute is necessary for SDHI to function. It uses the ability to have more than a chute than RealChute offers. Stock makes horribly broken messes when you try to slap two parachutes on a part.

[Kerbas_ad_astra]

RealChute has been updated for a while now. The other good thing about RealChute is that if you don't want the extra fluff, you just.. don't use the extra fluff?

Some time ago, I was starting to run into memory-cap issues and investigated switching over to 64-bit, which would preclude using RealChute (extra features or not) in any case. Hence this patch, to get exactly the functionality I wanted. I ended up not using 64-bit (got some more memory savings via ATM by making a few more configs -- and thankfully so, since 0.25 64-bit stock was choppy as all-get-out on my machine, never mind all the mods I wanted to use), but I still had this thing, and decided to put it out here when 0.90 arrived. Sorry for not noticing your update -- I saw "[paused]" some time back and put RealChutes out of my mind after that.

There are absolutely no compatibility problems with this.

Glad to hear it from the expert!

Because RealChute is necessary for SDHI to function. It uses the ability to have more than [one?] chute [that?] RealChute offers. Stock makes horribly broken messes when you try to slap two parachutes on a part.

Nifty! Thanks for the explanation.

Hey guys,

I'm running NEAR, and would like to slow the stock chute speeds down to a reasonable level. Unfortunately, the default settings seem to be a but too slow as i'm easily above 100m/s when I arrive on the ground. I've tried a few other changes but I can't seem to find a happy medium (I'm aiming for below 5G's on landing).

I thought I had tried this config out with FAR and found it okay, but that was "way back" (heh! ) in 0.25, and FAR and NEAR have both been updated (and not just for compatibility) since then. Unfortunately, I won't be able to do any testing for a few days yet. That said, I remember reading in the Deadly Reentry OP that main chutes can be safely deployed in the neighborhood of 3 km, so it may be that you'll need to increase the deployment altitude (both pushing the 'stage'-button sooner and increasing the multiplier in the patch -- to 4x?) to give the chutes more time to work.

EDIT: And also reduce the deployment time multiplier for additional effect (which it sounds like you've tried on its own) -- with stock aero, 50x kept G-force below 5 G's, if I recall my testing correctly.

Edited December 19, 2014 by Kerbas_ad_astra

[mjak]

I thought I had tried this config out with FAR and found it okay, but that was "way back" (heh! ) in 0.25, and FAR and NEAR have both been updated (and not just for compatibility) since then. Unfortunately, I won't be able to do any testing for a few days yet. That said, I remember reading in the Deadly Reentry OP that main chutes can be safely deployed in the neighborhood of 3 km, so it may be that you'll need to increase the deployment altitude (both pushing the 'stage'-button sooner and increasing the multiplier in the patch -- to 4x?) to give the chutes more time to work.

EDIT: And also reduce the deployment time multiplier for additional effect (which it sounds like you've tried on its own) -- with stock aero, 50x kept G-force below 5 G's, if I recall my testing correctly.

The chutes semi-deploy around 22K, which I believe is because they are linked to the atmospheric pressure. Full opening (default 500m) will not go any higher than about 1000m. It almost seems to be a MM bug, but that's a pretty stable/simple product so I'm leaning toward user error. Do I need to erase the MM cache files every time I change something? I've set the multiplier higher, up to *=8 (which should be 4000m), and still get the default behavior.

[Kerbas_ad_astra]

You can verify that the parameters have changed by hitting Alt+F11 in the Space Center view. That brings up a debug menu that lets you (among other things) view the cache and see what MM has changed the parts to, and check the values.

Another possibility that I thought I had indicated could be an issue in the OP, but (if this turns out to be the issue) I may need to state more clearly (or with bigger text?). I tested this patch by (among other things) launching Kerbal 2's, and when I just loaded up one on the launchpad, the full-deployment altitude would be 500 m, even though I had changed it with this patch, but when I went into the editor, the parachute parts in the menu all had the changed altitude, and if I removed and replaced the parachute before launching, the parachute would have the changed deployment altitude. I suspect that this is because that's a tweakable parameter, and so even though the default deployment altitude has changed, the Kerbal 2 craft file still has the 500m deployment altitude listed in its parameters (and it does, having just checked this in the files), which is not overridden by this patch. I suppose that may also affect all craft saved in the editor or launched before adding this patch to an install. I'll add that to the testing plan (and the OP, if it turns out to be what you're experiencing).

Deployment speed, however, is an internal module parameter, and not a tweakable per-craft piece of information, so that would (should) change on any and every vessel.

In other news, hazens1 suggested that toadicus should make a mod to turn deployment speed into a tweakable parameter, and he likes the idea, so that will be happening...sometime...probably sooner than I would have made it myself, for sure!

[mjak]

Now that you mention it, I do recall the deployment speed changing. It just was impossible to find a happy medium when I only had 500m to work with. I'll run a few quick tests and get back to you.

[Kerbas_ad_astra]

So, TweakableEverything now has a TweakableParachutes module -- thanks, toadicus! I'll update the OP when I've had a chance to try it out (and after I finally get around to testing how parachutes behave when this patch is added to a save with rockets already in flight -- mjak, any results?).

[Kerbas_ad_astra]

My test results are as follows:

1. Adding SlowChutes to a save that has a vessel in-flight will change the deployment speed, but not the deployment altitude.

2. SlowChutes does work with NEAR, but it does need more than 500 meters to fully open (which, as I've said, isn't touched on vessels which were only made or launched before "installing" the patch -- you will probably have to adjust it yourself -- I'll see about editing the OP to make that clearer).

Also, I've just tested toadicus's new TweakableParachutes module, and it works great! My emergency chutes snap open, while the regular chutes are nice and gentle. I'll put a big note to that effect in the OP and change the title to indicate that this patch has been superseded (I'll still leave this up, though -- it's simple and version-agnostic, so long as there's a compatible 2.x version of Module Manager to be had).

EDIT: but do not use both or TweakableParachutes' multiplier will stack with mine, resulting in parachutes which take a stupendously and dangerously long time to open! I figured this out the hard way during testing, when I forgot to remove my patch before testing TweakableParachutes for the first time. I should have noticed the unusually low deployment-speed indicator in the editor, but it didn't sink in until I crashed the test vehicle...

Edited December 31, 2014 by Kerbas_ad_astra