How to "amplify" a force and physic using AddForceAtPosition?

Question

I have the object in the image.

The red box is kinematic: when an object hit it , i set kinematic to false, so Unity apply normal physic.

But I would like to apply also a force to the point indicated by the violet cross.

So I'm using Rigidbody.AddForceAtPosition

_rb.AddForceAtPosition (ForceDirection * ForcePower, PointForcePosition.transform.position, ForceType);

PointForcePosition is an empty GameObject child of the red box object, placed where violet cross is pointing.

My question are:

1. Force Position: can I use that approach (an empty gameObject placed where i want to apply force ) ?
2. Force Direction: is it corret a Vector3 ( 0 , -1 , 0 ) to indicate a down force
3. Which ForceMode is the best for my purpose ? Impulse ? Force ?

Thanks

Answer 1

Since the image is not showing I may not be understanding properly what you're asking but here's my best crack at your questions:

Force Position: can I use that approach (an empty gameObject placed where i want to apply force ) ?

If the purpose of the object is just to store a transformed position there's other options, but your way is fine (especially if you want to tweak its position in the editor).

Force Direction: is it corret a Vector3 ( 0 , -1 , 0 ) to indicate a down force

That depends on what conventions you're using for your coordinates but down being the negative y axis is very common.

Which ForceMode is the best for my purpose ? Impulse ? Force ?

The difference between the two can be confusing but Impulse is effectively 'per frame' and Force is 'per second'. Roughly speaking, Impulse is better when you're applying a force over time (e.g. you're adding the effect of a rocket engine every frame) and Force is better for 'instant' effects (e.g. an explosion). From what you describe Force seems a better fit.