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llVolumeDetect

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function
Function syntax
llVolumeDetect(
  1. integer detect// Boolean. If TRUE, enables VolumeDetect; if FALSE (default), disables it.
);
Energy
10

If detect is TRUE, VolumeDetect is enabled, physical object and avatars can pass through the object.

This works much like Phantom, but unlike Phantom, VolumeDetect objects trigger collision_start and collision_end events when interpenetrating. Collision events will trigger in any script in the object.

How to use
llVolumeDetect(0);

Specification

Section titled “Specification”

Events queued depending on type

VolumeDetectPhantom
Events
Supported		collision_start

collision_end		land_collision_start
land_collision
land_collision_end

Differences

Section titled “Differences”

There are a couple differences in how Phantom and VolumeDetect handle collisions; specifically which events are supported and how they handle the ground.

VolumeDetect
Section titled “VolumeDetect”
  • When physical they fall through the ground with the risk of going off-world.
  • collision events are not triggered
Phantom
Section titled “Phantom”
  • When physical they collide with the ground but will not pass through (normal physical object behavior), land collision events are queued.

Caveats

Section titled “Caveats”
  • It can only be applied to the root prim (which will make the entire object VolumeDetect).
  • If the volume detecting object is not physical, it can only detect physical objects and avatars. If the object is physical, it can detect its collisions with static and keyframed motion objects as well.

Attachments

Section titled “Attachments”

Note: Attachments are not included in the avatar’s bounding box. Collision events received by attachments are collisions the avatar is having with the world, not collisions the attachment is having. Nothing actually can collide with an attachment1.

  • It is meaningless to enabled on attachments. Attachments cannot collide with anything.
  • Attachments do not receive collision events for avatar collisions with VolumeDetect objects.
    • Attachments do receive collision events for avatar collisions with non-VolumeDetect, non-phantom objects.

Examples

Section titled “Examples”
Example 1
default
{
    state_entry()
    {
        llVolumeDetect(TRUE); // Starts llVolumeDetect
    }
    collision_start(integer total_number)
    {
        llSay(0, "Detected!"); // Tells you when something penetrates the prim
    }
}

Known issues

Section titled “Known issues”

From the issue templates included by the wiki article:

  • SVC-2490 (bug): llCollisionFilter completely ignored after call to user-defined function and then a call to llVolumeDetect(TRUE)
  • SVC-8141 (bug): Volume Detect objects are not always allowing objects to pass through.
  • SVC-2996 (fs): llDetectedLinkNumber returns 0 with llVolumeDetect(TRUE)

See also

Section titled “See also”

Functions

Section titled “Functions”

Events

Section titled “Events”
Original wiki source

Some wiki templates and tables need their original context. View this article on the Second Life Wiki. Technical wording and examples are retained from the source; historical guidance may differ from current behavior.

Footnotes

Section titled “Footnotes”

  1. Even if attachments were included in an avatars bounding box, you would not like the outcome, the avatars bounding box is not deformed by animations. ↩