Problem with child following parent

Ok I have the problem that a child isnt following the parent through animation.
On detail, I created two cubes and one is the child of the second. And the parent
cube gets a soft-body physics. When I play the animation with Alt-A the parent cube
falls down but the child inst following! I also tested it with constraints without success.

here is the blend file to check:


the reason it doesn’t follow is because the object is parented to the object centre

because it is a soft body - the vertices are being animated (not the actual object)

how to do fix it?

well 2 ways
-parent the cube object to a vertex
-or use the game engine physics so the object moves (not just the vertices)

Yeah it works now, thanks waylow.

But some principle thing. When should I use the game physics engine and when the physics over object buttons, is there a principle way to do? For example I want to create
an car animation, so what would be the best way?

Because I also have some problems now with the game physics, because when I create a cube with all necessary options under logic section the cube will fall down to the ground expected. But when I move the cube now a little bit to another position and press “P” for start game engine, the cubes position will return to the frist one and fall down. So it seems that the game engine didnt update to the new position! So what Im doing wrong?

Ok got the problem, I have to remove all keyframes in IPO window :wink:

But if someone could explain me the difference about game physics and the physics buttons under objects, and what I have to use for a car animation would be nice, thank alot!

I’m not that great with the game engine but the difference between the game engine physics and the physics buttons is the game engine physics use the game engine to do the calculations and the others don’t - sounds simple

I think the thing to be aware of in your case is this

every object has a centre (the pink dot)
this is where blender sees the data as a whole in 3D space
inside that object you have vertices
if you animated the vertices - the pink dot will stay in the same spot
if you animate the pink dot - the vertices will move with it

if you are doing a car animation - the whole object (pink dot) can move so you wont have the parenting problem

you can put the car on a path or simply just key frame the position and anything you parent to it will follow