Use radius and rotation, to add linearVelocity to object.

Game Engine Game Engine Support and Discussion
1

So Object “Player” needs to have linear velocity added
Along a constantly changing vector, to be able to ride a platform that is rotating around a point.

We have Radius (distance from rotation center to ray.hitPosition)
And a property (last frame object rotation) and this frame rotation to get
Rotation difference.

So I need to use this data get a vector and a velocity to add to the player to match velocity with a rotating object under him.

I think I can use distance/time to get linV but how do I get the vector to add the force along?

2

Since I hate math I would do some sort of hackish workaround where you parent the player to the platform if no movement is occurring and then unparent on movement.

Also, can’t you set up the physics so that the player just stays on the platform? OR copy the linV of the platform to the player?

I’m just throwing out ideas here based on my general hatred of math.

3

Let the physics engine handle it:

  • Use forces or servomotion with a target object
  • Make sure the friction values are sufficient to stop the player sliding off.
4

But when the player walks things get dicey. I think I will try to use servo motion to move, and see if that fixes it, as linearV does not seen to work.

5

Im not quite sure what your trying to get at. If your standing on a rotating platform and your trying to match your rotation speed to the rotation speed of the platform based on how far away from the center point it doesnt matter, just match the speed. Whether you are standing in the center or 50 yds away your rotation speed stays the same. You are just traveling faster forwards.

However If your walking forwards on a circular platform and your trying to set your rotation match to match the arc of the circle so you dont fall off at x forward speed. You just use rotationspeed = forward speed / distance to center. It will change your rotation speed to match your forward speed so you always are following the arc. Heres an example:

The top 3 cubes all have the same rotation speed even though they are all at different radius’. You can tell they still match up.

In The bottom example the cube will adjust its rotation speed according to its forward speed and the distance to the center so it matches the arc regardless of your forward velocity.

turnstuff.blend (451 KB)

If ive completely missed what your talking about I apologize