Collisions

In SL, a collision occurs when two objects make contact (impact, collide) in-world. Phantom objects do not cause collision events unless llVolumeDetect is used, except in the case of land collisions.

A script can have a stack/heap collision.

Attachments will not trigger collision events if the object itself collides with something else. However, if the avatar collides with the object, the collision event is triggered.

Note: collisons are not "touches", which is when a user clicks ("touches") on the object with their mouse cursor.

Function	Purpose
llCollisionFilter	Limits collisions to a specific name or key, so only collisions with a certain object(s) or agent(s) will trigger them.
llCollisionSound	Replaces or disables the sound the object makes when something collides with it.
llCollisionSprite	Replaces or disables the particles the object emits when something collides with it.
llDetectedGrab	Returns the direction the detected object is being dragged in.
llDetectedGroup	Returns TRUE if the detected agent/object is in the same active user group.
llDetectedKey	Returns the key of the detected agent/object.
llDetectedLinkNumber	Returns the link number that triggered the collison/touch event.
llDetectedName	Returns the name of the detected agent/object.
llDetectedOwner	Returns the key of the detected agent/object's owner.
llDetectedPos	Returns the position of the detected agent/object.
llDetectedRot	Returns the rotation of the detected agent/object.
llDetectedType	Returns the detected object type (AGENT, ACTIVE, PASSIVE, SCRIPTED).
llDetectedVel	Returns the velocity of the detected agent/object.
llPassCollisions	In a linked object, passes collison events from a child prim containing a collision event to the parent.
llVolumeDetect	Turns the object phantom and triggers collision_start and collision_end events when an agent/object intersects it.

Event	Triggered
collision	while agent/object is colliding with the object containing the script
collision_start	when agent/object starts colliding with with the object containing the script
collision_end	when agent/object stops colliding with with the object containing the script
land_collision	while the object containing the script is colliding with the ground
land_collision_start	when the object containing the script starts colliding with the ground
land_collision_end	when the object containing the script stops colliding with the ground

Resources

• tunneling, Andrew Linden, 5/29/05

---

Functions | Events | Detection | Physics