The physics engine supports three events:
EVENT_FRICTION, EVENT_IMPACT, and EVENT_ENTITY

EVENT_FRICTION (called for all involved PEs) sets both TARGET and NORMAL to collision point and its normal.
EVENT_ENTITY (moving PE/collider) and EVENT_IMPACT (receiver/collidee) only have TARGET set.

Please note that there was some change in this behavior and one of the flags was undefined, I do not remember which version number contains the complete implementation (it might be the Beta release).

Fantastic, thanks Marco!

Very very nice! I'll update my white paper with this new very useful insight!

From the manual:

EVENT_friction
entity.enable_friction
If a physics entity collides with another model, the physics entity will receive this event. TARGET and NORMAL are set to point of impact and hit surface normal, respectively. If two physics entities collide, each will receive an EVENT_FRICTION

I've read all three events and it is in no way clear whether these events are exclusive to PE, ent_move, or both.

I seem to remember that the same laguage was/is used with ent_move events in the pre-PE days and thus my confusion; if memory serves, a physics entity was synonomous with an ent_move entity.As an example, quote from the manuel:
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EVENT_BLOCK
entity.enable_block
Collision with a surface of the level during a ent_move or c_move instruction or physic entity movement.
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Yet a Physics Entity under the PE would not generate this event by what marco jsut said
The wording is not consistent


The manuel should make clear which events are under the ent_move and which are under the PE.

The way events are presented right now is very confusing.

So Macro, I guess this means no Trigger events for the PE right now then? If so the when.

What I take away from this thread is that you don't need a trigger function...the above mentioned events can be used to trigger something on contact. Anything else and you should use scan or trace which work fine on PE entitys.

That's what I am getting too. I have some code that uses trigger to pull a ball through a tube but it uses trigger. I have altered it to use impact though. Thanks.