Problem with the TR-38-D decoupler

[Frank_Black]

Hi, everyone~ Here I got a problem with the TR-38-D decoupler. I made a rocket with 4 stages, and all of them are jointed together with TR-38-D. The first stage and the second stage were OK when I decoupled them, but when I decoupled the third stage, it just exploded, and damaged the engine of the fourth stage. I do not know why it worked like this. Does somebody have any ideas? Thanks~

Edited May 1, 2014 by Frank_Black

[xcorps]

If you are using the new decoupler, it's possible you're running into the physics bug (especially if there are struts involved). If so, here's how you can fix.

New Decoupler (TR-38-D) causes crash when staging (linux/mac) or parts of the ship to follow around (windows) – [FIX]

When staging, the new decoupler (TR-38-D) causes a variety of problems depending on your operating system. This problem seems to be worse if struts are involved. Thanks to Kasuha, the problem was narrowed down to the physics of the decoupler and is easily fixed.

1) With a text editor (such as notepad) open up the part.cfg file for the TR-38-D. It should be located in KSP\GameData\NASAmission\Parts\Size3Decoupler\part .cfg

2) Find the line that says “PhysicsSignificance = 1†and change it to “PhysicsSignificance = 0â€Â

3) Save the file and restart KSP.

Rep to claw....

[RocketPilot573]

Yep, just remove that evil “PhysicsSignificance = 1†line and you'll be fine.

[RW-1]

Totally Kewl!

This was driving me mad, but only began last week, I'm running stock, no mods, will implement tonight.

[Frank_Black]

Rep to claw....

Oh, I see.. sorry to bother you again but what is the meaning of this modify? Does it kill all physical features of the decoupler or just fix this bug? Thx~~

[undercoveryankee]

Oh, I see.. sorry to bother you again but what is the meaning of this modify? Does it kill all physical features of the decoupler or just fix this bug? Thx~~

The PhysicsSignificance flag is counterintuitive. PhysicsSignificance=0 means the part acts as a normal physics object with mass, drag, etc. PhysicsSignificance=1 tells the game to disregard the part's mass and drag in flight.

In 0.23, there weren't many physicsless parts. I know plane landing gear, ladders, and cubic octagonal struts, but those are the main ones you'd encounter.

0.23.5 makes more parts physicsless, including radial batteries, small science experiments, RCS blocks, OX-STAT solar panels, and probably lights.

The new decoupler being physicsless out of the box was possibly an oversight since the smaller decouplers didn't change. By making it physicsful, your ships will be a tiny bit heavier in flight and possibly experience a little more flex at this decoupler's joints. That's the worst case I can think of.

[Claw]

Oh, I see.. sorry to bother you again but what is the meaning of this modify? Does it kill all physical features of the decoupler or just fix this bug? Thx~~

PhysicsSignificance = 1 makes a part "Physicsless"

Making a part "Physicsless" changes how the game looks at the part during certain calculations, in addition to simply ignoring the mass. For the decoupler, it caused problems because the decoupler would sometimes disappear, or unlink from objects it just decoupled. This caused all kinds of problems in the background of the programming which often leads to crashing or other strange behavior.

So doing that fix posted above actually turns the physics back ON for the part and fixes the confusion for the program.

[Frank_Black]

The PhysicsSignificance flag is counterintuitive. PhysicsSignificance=0 means the part acts as a normal physics object with mass, drag, etc. PhysicsSignificance=1 tells the game to disregard the part's mass and drag in flight.

In 0.23, there weren't many physicsless parts. I know plane landing gear, ladders, and cubic octagonal struts, but those are the main ones you'd encounter.

0.23.5 makes more parts physicsless, including radial batteries, small science experiments, RCS blocks, OX-STAT solar panels, and probably lights.

The new decoupler being physicsless out of the box was possibly an oversight since the smaller decouplers didn't change. By making it physicsful, your ships will be a tiny bit heavier in flight and possibly experience a little more flex at this decoupler's joints. That's the worst case I can think of.

Thank you so much for your reply~ Can I make all parts physicsful? Because I think that the more physicsless parts, the less reality will the whole game behave like.

[Frank_Black]

Thank you so much for your reply~ I've got it~

- - - Updated - - -

PhysicsSignificance = 1 makes a part "Physicsless"

Making a part "Physicsless" changes how the game looks at the part during certain calculations, in addition to simply ignoring the mass. For the decoupler, it caused problems because the decoupler would sometimes disappear, or unlink from objects it just decoupled. This caused all kinds of problems in the background of the programming which often leads to crashing or other strange behavior.

So doing that fix posted above actually turns the physics back ON for the part and fixes the confusion for the program.

Thank you so much for your reply~ I've got it:)

[undercoveryankee]

Thank you so much for your reply~ Can I make all parts physicsful? Because I think that the more physicsless parts, the less reality will the whole game behave like.

If you set PhysicsSignificance=0 in every part config that mentions PhysicsSignificance, the only real consequences will be mass, flex, and possibly overall game performance if you're calculating physics on a lot of formerly-physicsless parts. (Some complex constructions of cubic octagonal struts may turn out to be more stable if you keep the cubes physicsless, but I haven't tested that.)

A few parts, such as landing gear, are dynamically set to physicsless without mentioning it in their .cfg files. I haven't heard of any good way to change those.

[Frank_Black]

If you set PhysicsSignificance=0 in every part config that mentions PhysicsSignificance, the only real consequences will be mass, flex, and possibly overall game performance if you're calculating physics on a lot of formerly-physicsless parts. (Some complex constructions of cubic octagonal struts may turn out to be more stable if you keep the cubes physicsless, but I haven't tested that.)

A few parts, such as landing gear, are dynamically set to physicsless without mentioning it in their .cfg files. I haven't heard of any good way to change those.

OK, I see Thank you a lot~