Custom part explodes on launch

[VR_Dev]

I'm so close to being done with this.

But I went back to blender to remove extra polygons on some of the parts and now two of the parts explode on launch. It doesn't have anything to do with my blender changes, because I tried the original blender models and they explode now too. THe only thing the logs say is that there is a structural failure between the part and whatever it is attached to.

Here is the .cfg that worked originally and now doesn't. I set this and the model up exactly like the other 15 parts, I like to think I have some idea what I'm doing, but this has me stumped.

PART
{
// --- general parameters ---
name = ScytheArm4
module = MuMechServo
author = Sirkut & Devo & clown_baby

// --- asset parameters ---
mesh = NewModel.mu
scale = 1.8
rescaleFactor = 1.8
specPower = 0.1
rimFalloff = 3
alphaCutoff = 0

// --- node definitions ---

node_stack_bottom = 0.0, 0, 0.0 , 0, -1, 0.0, 3
node_stack_top = 0, 0.18, 0, 0.0, 1.0, 0, 3


// --- editor parameters ---
TechRequired = advConstruction
entryCost = 0
cost = 50
category = Structural 
subcategory = 0
title = Lower Fury Leg
manufacturer = Magic Smoke Zoids
description = Lower leg for the Fury. Is used for both legs. Rotates.

// attachment rules: stack, srfAttach, allowStack, allowSrfAttach, allowCollision
attachRules = 1,0,1,1,1

// --- standard part parameters ---
mass = .05
dragModelType = default
maximum_drag = 0.2
minimum_drag = 0.2
angularDrag = 2
crashTolerance = 999
maxTemp = 3000
breakingForce = 999
breakingTorque = 999

// toggle parameters
rotateJoint = True
rotateAxis = 1, 0, 0
keyRotateSpeed = 20.0
rotateLimits = True
rotateMin = -180.0
rotateMax = 180.0
rotateLimitsRevertKey = False
jointSpring = 0
jointDamping = 10
onActivate = False
rotateKey = up
revRotateKey = down
fixedMesh = Base
servoName = ScytheArm3
invertSymmetry = False
motorSndPath = MagicSmokeIndustries/Sounds/infernalRoboticMotor		// Motor loop sound path
}

Here is a download link with the .blend file, .unity file, and game folder with the .mu and .cfg. I would be so appreciative of any suggestions you might have. I'm truly stumped. thanks

http://www.megafileupload.com/en/file/527116/Part-zip.html

The part in question

Edited May 6, 2014 by clown_baby

[NoMrBond]

Parts I've had randomly explode or spontaneously disassemble have been (thus far) collider issues

If you have a convex collider on both the Cylinder and Cylinder_001 meshes (I'm assuming the black and red parts respectively), then they might be clashing in a way the game doesn't approve of. You might need to make some custom simple meshes to hang the colliders on so they don't intersect

[VR_Dev]

That part has no convex collision meshes. Im trying to improve fps by not using convex on smaller parts. I've tried adding convex but still blows up.

[VR_Dev]

Also only the black cylinder has a collision mesh. The red cylinder has to sit inside another part, so I didn't give it one. I've used this technique for other parts with no problem

[PolecatEZ]

Try throwing this line into your config somewhere:

PhysicsSignificance = 1

Also change your attach rules: attachRules = 1,0,1,1,0

If that doesn't work, try:

PhysicsSignificance = -1

After that, try the nuclear option:

1) Go all the way back to Blender.

2) Modify the part with a 3rd piece that's static...doesn't move with the animation. Make it big enough to click on when its in the game, otherwise doesn't matter how you artistically do it.

3) Export just that new piece separately as a Blender file, no animations.

4) In Unity, make this the first part in the tree under the empty scytheArm4 transform and give it a collider, make it convex. Be sure to use the attach rules from the list above.

5) Now import your .fbx with the animated parts and make that a child of the base part - no colliders.

KSP handles things oddly if the entire part is involved in the animation. See the lateral docking port in B9 or stock inline docking port for examples. Activating it twists the physics of any nearby parts into knot, regardless of colliders. I used to think that the doors/hatch covers for those parts were just badly designed with the colliders left on, but after poking at them in Unity I saw that wasn't the case. I ran into the same issue making a 1.25m cargo bay, where opening the doors (with no colliders) would still twist up my aircraft.

Disclaimer - I have no idea how well the above solution will play with IR, theoretically if everything is using the attach nodes, it all should move like its supposed to.

Edited May 15, 2014 by PolecatEZ