aircraft animation


I just would like to know how to animate parts of an aircraft for BGE :

  • aileron
  • landing gear

Must I use shape key ? bones ? other ?


I didn’t worked with BGE much yet but I guess you wanna take a look at bones/rigging

Alternatively use rigid body constraint and apply force with the ‘motor’ feature. That’s more simulation than animation but it do the job. If needed You can have a script implementing all kind of servo controls (but keep the mechanical complexity low - else bullet bug out in my experience).

I have been thinking about this too, and its a complicated question.

Flaps could be done with a child object that is rotated with an offset origin and a constraint, or maybe f-curves. I’ve never used bones so I cant comment on them.

Landing gear is tougher, as you have not said what type of gear it will be-are we talking retractable, fixed (sprung) etc?
Retractable would be a simple F- curve, (play animation linked to a ray pointing down, maybe, when the ray senses the ground, it plays the animation forwards = gear down, play backwards when ray does not see the ground = gear up). When the gear is retracted, you might want to set its collision to none to cut down on processing time, depending on the collision hull you want.


Controls like aileron, elevator, rudder, stick/yoke, pedals, throttle etc animated with property controlled f-curves.

Landing gear dunno.

Thanks for your replies

christiani_if, I watch your helicopter model and I saw you splited the model in many objects.

Is it possible to have the same result but all in one object (to have only one UV texture) ?

I tried to use f-curves but it seems to work only in “object mode” not in “edit mode”. So I can’t deform object but only rotate, move, etc

Maybe I didn’t understood what you said me …

I don’t know if the best approach would be to have a single object for the entire aircraft, but you could try the following thing:
-finish your model, unwrap it, put materials on it, texture it, just finish it
-now go to edit mode, select the faces/parts you would like to be in motion, press P ->choose “Selected”

You can have 1 UV(or 1000) texture no matter how many objects are using it, just make sure the unwrapping is well made.

Shape keys are the only thing you could try to do, see if this model (it opens hatches in order to fire) is an approach you might be aiming for:

Still, I don’t know how “easy” your attempt will be (since I don’t know what collision or other types of problems may appear), but you can always choose a different approach (provided that the same results can be achieved, without a big loss in game performance or bugs)

Bones are just another “approach” of the shape keys, the only difference being that by using bones you can much easier handle things made of multiple segments (since this is quite the only way to have “parts” working as children and parents when working with a single object).

I tried to use f-curves but it seems to work only in “object mode” not in “edit mode”. So I can’t deform object but only rotate, move, etc

F-Curves works only with objects. If you want to deform a mesh you must use shape key or bones.
If you use bones don’t forget the Armature modifer on the mesh.


gear.blend (188 KB)

If You uv-map first and split after You can have the same uv texture.

It make later changes harder but doable. In worst case You can join the objects, remap and then split again by disconnected mesh pieces.

But it will still render in different batches :frowning:

To animate one and the same mesh I think You need to use bones or possibly shapekeys - and that will not update the collision mesh (but You can bone parent invisible collision object - but I don’t know how well it interact with the main collision box - fix for that is waiting for trunk thou - cucumber branch if I remember correctly).

You could also split your object’s (main aircraft) collision into multiple parts, by using custom collision boxes(is it possible?). You could try to add/remove gear collision boxes when they emerge/retire inside the aircraft. See if this link is of any use to you(your aim is to add multiple “sub-collision” boxes for a single object):

So for collisions, it isn’t recommended to use shape keys and/or bones

The best solution is f-curves like the helicopter model of christiani_if :

  • finish the model
  • unwrap texture
  • split in multiple objects
  • use f-curves for animations

Sorry to ask again a confirmation but I’m really a novice in BGE

Frankly, I had not thought about collisions … so if you are others suggestions to avoid common mistakes


Best suggestion - experience. Work a lot with blender, and everything will sort out :slight_smile:
Practice really is an important factor, even if it doesn’t seem to be one (at first glance).

P.S. Decide your targets well and try some “dummy models” where you could see if what you’re trying to do can be done or not. What I mean is to test all of the involved features (and processes) on a different model than the one you want to edit, so you can be certain you will not encounter hard-to-undo mistakes.
Just be sure of what you’re willing to achieve, and you will be OK :yes: