ferram4

[1.3] Kerbal Joint Reinforcement v3.3.3 7/24/17

Recommended Posts

After several launches with this plugin - I am seeing two things that are odd. First, a larger ship had some odd springing / sliding between a 1.25m fuel tank (the core booster of the launch stack) and a KW rocketry 1.25m -> 2.5m adapter. The net effect was like the traditional wobbly rocket. The parts didn't break, and the oscillation settled down late in the launch.

Second, procedural fairings don't eject away now - they separate, but they stay roughly in place through the rest of the flight to orbit. During a MechJeb-controlled launch, they slowly clip through the ship during the warp between 69km and apoapsis. They fall back down to Kerbin just fine afterwards. I've seen this on 5 of the 6 launches I tried (different ships each time). I am using a KOSMOS procedural fairing model, on top of a KW rocketry 2.5m fairing base that I tweaked to support procedural fairings, so it may be something specific to one of those.

Share this post


Link to post
Share on other sites

I've not seen any slidey engines or other silliness tonight which is positive. My large rocket with a multi-stage interplanetary command section docked to a 30 tonne heavy lander (tylo bound) flexes a bit less but still does the banana dance around the docking port and the booster decoupler under thrust. This isn't supposed to make things perfect though so that's ok, between lowering the throttle setting and stopping mechjeb from amplifying the oscillations with its attempts to counter the wobble it should just about work.

Share this post


Link to post
Share on other sites

@MOARdV: I've made some changes that I think will stiffen things up more, but understand that asking too much of a particular joint will always cause issues.

Procedural fairings not decoupling is something that I'll look into; a joint may not have been properly destroyed.

Share this post


Link to post
Share on other sites

I just tried testing the limits of this plugin by building the tallest ship I could manage. The ship consisted of a mainsail under three orange tanks, plus a bunch of small 1m tanks stacked end over end on top of the 2 meter probe core in the center of it all with extra reaction wheels at each end of the ship (very top and between the last orange tank and the mainsail engine). Added 4 SRB's near the bottom and another 4 offset 45 degrees half way up the orange tanks. Added an additional four winglets near the very bottom and another 4 at the very top. No struts on anything.

This would have horribly failed prior to this plugin. With it, it flew straight as an arrow. There's an ever so slight amount of bending outwards on the SRB's once they fire up, but nothing that caused any problems. Mechjeb took the super long ship up to a mechjeb perfect 100km circular orbit despite the top SRB's colliding and destroying the bottom winglets after detaching.

This will become part of my KSP setup!

Share this post


Link to post
Share on other sites

This mod has greatly improved my rocketry experience. I'm a fan of oversize payloads, but getting them into orbit was never an easy thing. I had performance issues, Kraken attacks even on Kerbin, spacecrafts flipping over or just going boom shortly after liftoff. But not any more.

Even with my old lifters (200+ parts eating up computer resources like a black hole), framerate is nearly doubled, and stability is better than ever. I've yet to test my enormous space station (half a hundred meters long), but I'm pretty sure I'll be able to turn it without snapping it in half.

For centuries, kerbals had been debating whether there is an almighty entity out there. Taking it into his hand, Jebediah Kerman decided to build enormous rockets to reach the furthest corners of the galaxy... but didn't find an answer, for his rockets would always explode before touching the sky. However, a god descended upon Kerbin and instructed Jebediah to build a temple, which later got the name of Kerbal Space Center. There, he had all the materials to fuel his sky-high ambitions, but the rockets still kept falling apart, claiming many kerbal's lives. The god was called Squad - although wise and good hearted, he didn't listen to the last prayers of victims wishing for more solid spacecrafts.

Until one day, another god approached Jebediah, and blessed all his structures with the strength of stone and swiftness of the wind. His name was... Ferram4.

Share this post


Link to post
Share on other sites

Alright, version 1.1 is out, making the connections a little stiffer. For reference, a 3.75m KW Rocketry decoupler can now handle ~160 tons of payload at ~5gs without severe flexing, unless you're desperately trying to flex it. No promises if you try to go higher than that.

Includes option to exempt specific part types or parts with specific part modules from having their joints stiffened to avoid conflicts with other plugin-based mods, if necessary. Documentation in the README.

Bugfixes include:

  • Doesn't conflict with Infernal Robotics anymore.
  • Extra stiffening properly applied to radial decoupler connections.
  • Procedural Fairings can't get magically stuck to the fairing base.
  • BreakForce and BreakTorque no longer have any effect at all on connection stiffness, only failure criteria.
  • Fixed situations where NullReferenceExceptions could be thrown.

Share this post


Link to post
Share on other sites
@MOARdV: I've made some changes that I think will stiffen things up more, but understand that asking too much of a particular joint will always cause issues.

Always have to make trade offs. FWIW, I tested the same rocket with the struts I had previously (which did not cross the part connection in question), and it did not have the same wobble. However, since you've already released 1.1, I'll go check it out now and see how that affects the outcome.

Share this post


Link to post
Share on other sites

Tried version 1.0 today and loved it! I did get some wobble between my payload and the decoupler it was mounted on. Four struts added from the top of the boosters to the payload stopped it. That was a fair trade since I was able to eliminate about 20 other struts between other parts of the rocket. Looking forward to trying version 1.1 tomorrow. Bravo!

Share this post


Link to post
Share on other sites

I must be having something odd happen, I'm no longer able to use decouplers whatsoever, because the decouplers don't come apart from the rest of the spacecraft.

There are no unusual messages in the debug-log, but this is kinda broken.

Share this post


Link to post
Share on other sites

I haven't seen any issues with things not properly decoupling; are there any particular parts / mods that that issue occurs with?

Share this post


Link to post
Share on other sites
Indeed, this should be stock instead of a mod.

Yep, in 0.23 may be, YAY.

This mod rockz with MJ on my Katurn & Koyuz heavy launch vehicles. less struts more fps Yo~

but the long stick still flex with stock SAS/ASAS tho.

Share this post


Link to post
Share on other sites

Ohhhh, yeeesssss! Finally, the Kerbals have bolts to connect their rocket components together instead of Blu Tack, chewing gum and duct tape.

What *is* the deal with having the rockets slam downwards a bit when physics kicks in? Many have been the launch vehicles that would be perfectly fine in flight with far fewer struts - if the game engine didn't start off with a body slam to the mat before launch.

Easy fix for eliminating the Lurch? Temporarily invoke Unbreakable Joints then do the physics initialization "off screen" to find out how much the rocket will drop. Once that's done, render the launch screen with the rocket placed at that calculated elevation with the launch clamps "pre drooped". If there's not enough clamps, render the carnage of exploding rocket and pop up a message about needing to

add more launch clamps.

If real rockets were set up like this game, they'd be hung from a crane, the supports attached then the supporting cable cut loose to let the rocket drop until all flex and slack in the supports was taken up. The result would be pretty much like what happens to an insufficiently strutted rocket in KSP.

Share this post


Link to post
Share on other sites

Ferram, don't think that's an issue, more of a graphical glitch, but I will report it anyways.

If you strut something to a stack decoupler(not that anyone will do it with your mod, but I had a design like that), when you decouple the strut connection "remains".

Just the struts become like an elastic rope and stretch to infinity as the decoupler and the whatever-was-connected-to-it move apart.

Share this post


Link to post
Share on other sites

Incredible work, ferram4, it was a long time since I've had so much fun flying large ships in KSP! Can't thank you enough.

I haven't seen any issues with things not properly decoupling; are there any particular parts / mods that that issue occurs with?

I have noticed stock radial decouplers not ejecting attached pieces properly (Radial Detachment Manifolds, I think), same as KW stack decouplers and KW fairings. Part stays entirely in place and you an only separate from it by changing your velocity (hopefully without slicing something off with a collision). I think it's not something with individual parts, - rather, it looks like ejectionForce parameter stopped working entirely. Not gamebreaking, but would be nice to have fixed. :)

On another subject, I think collisions with the ground are much more unforgiving now, at least with KW 2.5m engines and tanks exploding on a fairly gentle <5m/s touchdown. All the more reason to use nice suspended landing legs, but wouldn't hurt to look into.

Share this post


Link to post
Share on other sites

@Galane: Your idea for doing the physics lurch "off-screen" actually makes a fair bit of sense, though I'd invoke another constraint: instead of having unbreakable joints + suddenly load 1g, have breakable joints and gradually scale up gravity from 0.01g to 1g over the course of a second or two before giving control over to the player. That would allow the physics simulation to internally calculate the deflection needed without manually shifting parts around outside the context of the simulation, which has a tendency to cause Very Bad Things. The end result should be that if the clamps will still fail to hold the rocket that they will fail, but removes the large initial jerk and extra load at launch.

I will have to look into implementing that tomorrow; thanks for the idea.

@smunisto: And I think I know what's causing that. I added some code to manually break all strut connections when a stage decouples (somewhat leftover from trying to find a workaround for the "struts kill ejection force" bug). I'll look into fixing it.

@bac9: The "decouplers not applying forces bug" is something that I know about, but I don't consider it particularly critical since it's also caused by stock struts; I didn't think that was what he meant, since I actually did have some issues during development where the parts would stick to the rocket. Realistically, the best way to solve both issues would be a refactoring of the decoupler code so that it broke all joints between parts on different vessels before actually applying the ejection forces. Main problem is currently it requires a serious workaround (essentially, a new decoupler module) to make it work currently.

I will look into the parts failing on touchdown; I can't say I'm surprised, but it shouldn't be that severe; they should really just shear off, and at slightly higher velocities (read: ~15m/s). Odds are that the joints have become stiff enough that the current strengths are incapable of breaking them; as a temporary measure you can try looking in the config.xml and lowering the linear and angular "maxForce" values and decreasing the breakForce and breakTorque values to see if that helps.

Edited by ferram4
bac9 ninja'd me

Share this post


Link to post
Share on other sites

Bug report: mechjeb case wobbles around like crazy (at least when stuck to the side of the 3-man pod)

Other than that it's been amazing. My computer might be able to handle an Apollo mission now!

Share this post


Link to post
Share on other sites
Bug report: mechjeb case wobbles around like crazy (at least when stuck to the side of the 3-man pod)

Other than that it's been amazing. My computer might be able to handle an Apollo mission now!

try go to altitude control and set Tf to 0.9 , the default is 0.3 which flex long sticks alot.

Share this post


Link to post
Share on other sites

There's still some interference with Infernal Robotics. Load this craft without the KJR mod installed and click the arrow to extend the rails. They go down like they should.

http://pastebin.com/tfNJx78E

Now install the KJR 1.1 mod and extend the rails. Uh-oh. It's like they're pushing against a virtual floor, trying to push the rocket up, things break and go boom.

Edited by Galane

Share this post


Link to post
Share on other sites

Question, does this have an effect on docking ports?

I hate how wobbly docking ports are and would love to have them be more rigid.

Edited by Psycix

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.