FASA Launch tower tutorial

[frizzank]

Here is the launch clamp with the unity file so you can see how it is set up.

https://drive.google.com/open?id=0B5TWBhfzs3ZXTkVENjRUc1NRMEE

In the config there are several parts to the clamp that are mostly strait forward.

MODULE

{

name = LaunchClamp //name of the module do not change

trf_towerPivot_name = Cap //Name of the rotation transform that the Tower part is linked to

trf_towerStretch_name = Tower //Name of the mesh that gets stretched

trf_anchor_name = Base //Name of the mesh that snaps to the ground

trf_animationRoot_name = Walkway_Anim_Root //the empty game object that holds the animation and the animated parts

anim_decouple_name = Launch_Tower_Anim // name of the animation to play

}

When you build the parts in max you must use Y as your up direction in your viewport and set Z as your up axis when you export. For what ever reason the parts do not respect the rotation in unity if they are exported with any rotation to them. You can check this by making sure the rotation says 0,0,0 in the inspector in unity. If they are not 0,0,0 you will get weirdness.

Transform position is very important. The base transform position must be at 0,0,0 in unity, this is where it attaches to the ground. The transforms for the Tower (Mesh that gets stretched) Must be at the top and center of the mesh. The Tower mesh must also extend to the bottom of the base.

The cap is the rotation transform for the whole thing, if you mess part up nothing will work right. Blue arrow points towards your rocket and green is up. This transform should also be in the center of your clamp.

Also make sure the collision of the clamp does not intersect any collision of the rocket or it will explode when you launch. It helps if you put the attach node away form any collision on your clamp.

Edited January 11, 2017 by frizzank
Broken Link

[Justin Kerbice]

Thanks for this documentation frizzank.

(Moderators: it's possible to update the links list thread ?)

[Orionkermin]

Thanks for the tutorial and the example Frizzank. I've made a mock up clamp to get the process correct and I seem to be doing something wrong, but I'm not sure what. The object wont even appear in the VAB...

Javascript is disabled. View full album

Here's the cfg I set up for it:

PART
{

// --- general parameters ---
name = TestClamp1
module = Strut
author = orion

// --- asset parameters ---
mesh = model.mu
rescaleFactor = 1

// --- node definitions ---
// definition format is Position X, Position Y, Position Z, Up X, Up Y, Up Z
node_attach = 0.0, 2.344931, 4.657781, 0.0, 0.0, -1.0

// --- FX definitions ---

fx_gasBurst_white = 0.0, 1.354437, 0.8369194, 0.0, 0.0, 1.0, activate
sound_decoupler_fire = activate


// --- editor parameters ---
TechRequired = generalConstruction
entryCost = 1800
cost = 200
category = Structural
subcategory = 0
title = TestClamp
manufacturer = O.M.B. Demolition Enterprises
description = The TT18-A Stability Enhancer uses ground-breaking fastening technology to significantly increase the stability of spacecraft during the pre-launch phase. While OMB Demolition has been criticized in the past for using "big fancy words for a rocket holder" in their description of their device, none can say the TT18 series doesn't deliver rock-solid clamping action, as advertised. The owner's manual strongly suggests these devices be placed on the bottommost section of the spacecraft, and activated as soon as the engines are lit, for optimal de-clamping performance.

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

// --- standard part parameters ---
mass = 0.1
dragModelType = default
maximum_drag = 0.2
minimum_drag = 0.2
angularDrag = 2
crashTolerance = 100
maxTemp = 5000
fuelCrossFeed = False
explosionPotential = 0.1

breakingForce = 150
breakingTorque = 150

stageOffset = 0
childStageOffset = 0

MODULE
{
    name = LaunchClamp

	trf_towerPivot_name = TestClamp_Cap
	trf_towerStretch_name = TestClamp_Tower
	trf_anchor_name = TestClamp_Base

	trf_animationRoot_name = Animation
	anim_decouple_name = Test
}

MODULE
{
	name = ModuleGenerator
	isAlwaysActive = true
	OUTPUT_RESOURCE
	{
		name = ElectricCharge
		rate = 1
	}	
}

// ----- DO NOT EDIT BELOW THIS POINT ------

}

Any help from someone who has gotten clamps working would be fantastic as I'm up against a bit of a wall at the moment.

[frizzank]

are you in sandbox mode. otherwise you will not get anything...

[Orionkermin]

Yea, I do all my testing in sandbox mode. I have the base's transform at the scene's origin. Cap and Tower both have their transforms at the top of the tower object. Everything is facing z after import, so no rotations in unity.

Edit: OK, I got it working, turns out it was some kind of export issue with unity and the animation. Rebuilding the scene fixed it. Thanks again for your time, help, and this tutorial Frizzank.

Edited June 3, 2014 by Orionkermin

[NecroBones]

BTW, thanks for posting this, it REALLY helped me out.

I've suggested adding this to the great big mod link list thread.

One little tidbit that may help people too-- Having a "base" collision mesh at the ground level helps keep the foot from slipping around on the surface of the pad. However, it will want to jump upward to not intersect with the pad, so it shouldn't extend below the "ground level" in your design.

The base part can visually extend downward below this point, however, and it's a good idea to make it go down a good long way. These days, it's easy to build rockets that are wider than the pad, and the stock launch clamps currently look like they're floating over the ground if you use them outside the edge of the launch pad. The clamps I just made, have the base extend downward about 5m from the "ground level" (0,0,0), just to be safe.