I’ve made an aircraft model and I want to make a little free fly demo with it. The problem is that if I make it a rigid body it falls down. Tried to add an always sensor with a motion actuator and add force pushing it up but somehow the model still just falls somewhere. How can I make it stay afloat while being a rigid body?
Another question is about the motion. I added the basic controls but when I checked it the model moved based on the world axis. How can I make the model move based on it’s own axis?
How can I make the model move based on it’s own axis?
If you did logic bricks, there should be several L on the brick’s different types of motion or rotation to make it local. Python, like setLinearVelocity, you would change the false on the end to true:
object.setLinearVelocity((0, 0, 0), True)
I am not sure if this will affect the z axis movement, but to stop falling on a rigid body there are lockable axis of movement and rotation in the lower part of the physics tab.
I’m working with logic bricks. I found the local options but the fall down problem is still there. If I lock down the Z axis it wont fall down but it can’t move on that axis as well. Turning the world gravity to 0 affects the whole world which is bad 
How can I make only the chosen objects free from gravity?
If you add an upwards force of 9.8 to counter gravity your object will hover.
Can’t you just turn gravity to 0 in the world tab?
Nope.
That’s it 
Thank you! Now it works properly.
Hint: keep in mind the mass of the object (default 1.0). You need to multiply counter-gravity with mass.