Getting rid of decoupler shrouds in stock engines

[sumghai]

As part of a new Service Module parts pack I'm working on, I intend to make use of a copy of the stock LV-909 engine (via MODEL{} node referencing).

However, since the lower half of the service module will be encased in its own fairing, I'd like to get rid of the default one that came with the original LV-909. I've tried removing the ModuleJettison entry in the CFG, but this leaves the fairings always on.

Is there a way to completely remove decoupler shrouds in stock engines?

Edited September 3, 2013 by sumghai

[Tiberion]

Yep, its pretty easy;

In the jettison module, change this:

bottomNodeName = bottom

"bottom" refers to the node name that you want to "look for" when spawning the fairings. When something attaches to the bottom node, the node spawns. In the stock engines, the bottom node is always:

node_stack_bottom = 0.0, -7.27403, 0.0, 0.0, 1.0, 0.0

Just make sure they don't match, and no fairings will spawn.

[sumghai]

Much appreciated, thanks!

EDIT: It seems that the snippet completely breaks the engine.

I changed bottomNodeName = bottom to bottomNodeName = notbottom, and while the fairings do disappear in the VAB, the following happens:

- The fairings till show up in the flight scene regardless of whether there is a decoupler beneath it or not

- A strange particle effect is constantly running

- The engine cannot be activated or throttled, nor does it show up in the staging panes of the flight scene.

PART
{
// Kerbal Space Program - Part Config
// LV-T45 Liquid Fuel Engine (Fairingless)
// 

// --- general parameters ---
name = SDHI_Rockomax_LV_909_Fairingless
module = Part
author = Mrbrownce / sumghai

// --- asset parameters ---
mesh = model.mu
scale = 0.01


// --- node definitions ---
node_stack_top = 0.0, 21.6498, 0.0, 0.0, 1.0, 0.0, 1
node_stack_bottom = 0.0, -37.8251, 0.0, 0.0, 1.0, 0.0, 1



// --- FX definitions ---

fx_exhaustFlame_blue_small = 0.0, -21.0, 0.0, 0.0, 1.0, 0.0, running
fx_exhaustLight_blue = 0.0, -21.0, 0.0, 0.0, 0.0, 1.0, running
fx_smokeTrail_light  = 0.0, -21.0, 0.0, 0.0, 1.0, 0.0, running

// --- Sound FX definition ---

sound_vent_medium = engage
sound_rocket_hard = running
sound_vent_soft = disengage
sound_explosion_low = flameout

// --- editor parameters ---
cost = 750
category = Propulsion
subcategory = 0
title = LV-909 Liquid Fuel Engine (Fairingless)
manufacturer = Jebediah Kerman's Junkyard and Spaceship Parts Co.
description = Variant of the standard LV-909, designed for use with SDHI's Service Module System and fairings hastily removed with cutting torches.
attachRules = 1,0,1,0,0

// --- standard part parameters ---
mass = 0.5
dragModelType = default
maximum_drag = 0.2
minimum_drag = 0.2
angularDrag = 2
crashTolerance = 7
maxTemp = 3600

MODULE
{
	name = ModuleEngines
	thrustVectorTransformName = thrustTransform
	exhaustDamage = True
	ignitionThreshold = 0.1
	minThrust = 0
	maxThrust = 50
	heatProduction = 300
	fxOffset = 0, 0, 0.21
	PROPELLANT
	{
		name = LiquidFuel
        	ratio = 0.9
		DrawGauge = True
	}
	PROPELLANT
	{
		name = Oxidizer
		ratio = 1.1
	}
	atmosphereCurve
 	{
   	 key = 0 390
  	 key = 1 300
 	}

}

MODULE
{
	name = ModuleGimbal
	gimbalTransformName = thrustTransform
	gimbalRange = 0.5
}

    MODULE
    {
          name = ModuleAnimateHeat
          ThermalAnim = HeatAnimatioEmissiveLiquidEngine3
    }


MODULE
{
       name = ModuleJettison
       jettisonName = fairing
       bottomNodeName = notbottom
       isFairing = True
       jettisonedObjectMass = 0.1
       jettisonForce = 5
       jettisonDirection = 0 0 1

}
}

[Tiberion]

try adding a third node, making it size zero and in the middle of the engine so it can't be snapped to (without trying anyway) and name it to match your bottomNodeName as a workaround, to see if that stops the bugging out.

I've used this method in the past and it should work though.

[sumghai]

Success at last! Here's a full summary of Tiberion's technique, plus my own tweaks:

1) Always use model nodes to reference the original SQUAD models / textures

This allows re-use of existing assets and avoids duplication/redundant loading.

2) Add a "dummy" stack attachment node with a size of 0

This needs to be somewhere between the original top and bottom attachment node locations.

// --- node definitions ---
node_stack_top = 0.0, 0.216498, 0.0, 0.0, 1.0, 0.0, 1
[b]node_stack_hidefairing = 0.0, -0.378250, 0.0, 0.0, 1.0, 0.0, 0        // <---------------------[/b]
node_stack_bottom = 0.0, -0.378251, 0.0, 0.0, 1.0, 0.0, 1

One tip for preventing the VAB/SPH editor from still attempting to snap to this (visually) hidden node is to set its location very very close to but not the same place as the bottom attach node - in the example above, node_stack_hidefairing is 0.000001 units away from node_stack_bottom.

3) Set the fairing's "bottomNodeName =" to the dummy node defined in 2)

MODULE
{
       name = ModuleJettison
       jettisonName = fairing
       [b]bottomNodeName = hidefairing          // <---------------------[/b]
       isFairing = True
       jettisonedObjectMass = 0.1
       jettisonForce = 5
       jettisonDirection = 0 0 1

}

The PartModule will look at this dummy attachment node, and if something is attached to it, a fairing is spawned. In our case, because the hidefairing node is so close to the original bottom node, the VAB/SPH editor won't be able to snap anything to the former, and thus the fairings will remain forever hidden.

You should get the following result:

[Tiberion]

Awesome, glad it worked.