Modeling Engine Gimbals/Fairings

[Starbuckminsterfullerton]

I know there are a lot of threads asking questions about creating engines with gimbaling nozzles and fairings and such, and I have read them, and not seen this answered anywhere.

When modeling an engine intended to have a gimbaling nozzle and a fairing, let's say in blender, do you model them as separate projects with their own colliders/textures etc. and then import them into the same unity project? Or can you just make them separate objects in the same blender project? If the latter, do they need to be setup in a parent/child heirarchy first?

There are no videos or guides that I can find that follow the process of creating a full-featured engine from start to finish, so if anyone has a step-by-step, that would be invaluable. Especially if you can address the process of setting up thrust transforms (how do you get the engine bell to follow it as it gimbals? is is part of the body or the nozzle?)

Thanks to all of you that contribute to the information that's already available.

[SpannerMonkey(smce)]

HI all engine parts can be made in the same project, for gimbals you need the nozzle to be separated from the main mesh, same with fairings.

To get nozzle to move correctly center the pivot at the base of the nozzle, make the thrust transform a child of the nozzle then in the cfg

	MODULE
	{
		name = ModuleGimbal
		gimbalTransformName = nozzle
		gimbalRange = 4
	}

The fairing needs a special tag in unity Icon_Hidden to avoid showing in the build menu and thats about it really

[nli2work]

I've been meaning to do a video. probably in the next few days.

[Starbuckminsterfullerton]

HI all engine parts can be made in the same project, for gimbals you need the nozzle to be separated from the main mesh, same with fairings.

Does this mean they can be a parent/child family, or really completely separate? Also, forgot to ask but same question goes for collider models.

To get nozzle to move correctly center the pivot at the base of the nozzle, make the thrust transform a child of the nozzle then in the cfg

Perfect, exactly what I needed to hear. Thanks for your answer.

nli2work, I'll be on the lookout.

[SpannerMonkey(smce)]

Hi , just do your colliders in unity , making separate ones is a fairly old school method. You should have no issues with too many triangles in the convex collider unless your engine's constructed from spheres

[NecroBones]

Usually I make the nozzle mesh a child of the thrustTransform (that is, the transform is the parent to the nozzle). I didn't realize it could work the other way around.

The fairings and nozzles can be their own meshes in the project, as others pointed out. You don't need separate colliders though, unless you really want a moving collider. Many of the stock engines just use a single cylindrical collider for the entire engine, that includes the space taken up but the skirt/bell/nozzle. The LV-N is a great example of this. Try standing a ship right on the engine, with throttle at zero, and use your steering keys. You'll see the skirt pivot around, but the rocket doesn't tip over or rock around.

The fairing should NOT have a collider, IMHO. All of the stock ones are non-colliding. Even the LVN-like fairing panels won't need colliders, as the colliders are added automatically for those.

[Starbuckminsterfullerton]

The fairing should NOT have a collider, IMHO. All of the stock ones are non-colliding. Even the LVN-like fairing panels won't need colliders, as the colliders are added automatically for those.

We are agreed on this, there are very few instances where you would even notice that there was no collision.

I encountered another unknown in my continuing efforts to learn the dark art of unity, and that is positioning the thrust transform. From what I can see, you can't move any gameobject in relation to the models that are it's children, and so any nozzles I have look set up to pivot about their center of volume, not one end. is the fix to make the gameobject a child of the asset, like spanner says? And if I do it this way, what should be the nozzle asset' parent?

[nli2work]

set the object as the child's child temporarily, reset the object's transform (that will place it at the pivot of it's child). move the object where you need it in relation to the child. un-child the object from it's child, back to normal hierarchy setup you intend.

check the pivot setting buttons above the main scene window (under "Component" in main menu bar) make sure they are set to local/pivot; not global/center or global/pivot

there're some unity scripts online that adds decent alignment tools if you don't want to deal with hierarchy gymnastics.