# Difference between revisions of "Phys pulleyconstraint"

`phys_pulleyconstraint` is a point entity available in all Source games. It is a constraint that is essentially two length constraints and two points. Imagine it as a virtual rope connected to two pulleyed objects, specified in the Entity 1 (attach1) and Entity 2 (attach2) keyvalues, each suspended from a pulley above them.

Pulley point 1 - the pulley from which Entity 1 is always suspended from - is the origin of this constraint entity.

Pulley point 2 - the pulley from which Entity 2 is always suspended from - is the position of the "blue ball", set by altering the Pulley Position 2 (position2) keyvalue directly, or by using the Helper Tool.

The constraint keeps the sum of the distances between the pulley points and their suspended objects constant.

## Keyvalues

Additional Length `<float>`
Add (or subtract) this amount to the rest length of the pulley rope.
Pulley Gear Ratio `<float>`
Add (or subtract) this amount to the rest length of the pulley rope.
Pulley Position 2 `<vector>`
The position of the pulley for Entity 2. The pulley for Entity 1 is the origin of this constraint entity. Entity 1 is always suspended from pulley point 1, and Entity 2 is always suspended from pulley point 2.

TwoObjectPhysics:

Entity 1 `<targetname>`
Entity 2 `<targetname>`
The entities to constrain. Leave one or the other field blank to constrain to the world.
Note:Only one entity will be constrained, even if several share the given targetname.
Constraint System Manager `<targetname>`
A `phys_constraintsystem` that this constraint should be a part of. This avoids the "jiggling" caused by constraints applied to the same set of entities fighting with each other.
Force Limit to Break (lbs) `<float>`
Impact force required to break the constraint, in pounds. 0 means infinite. A way of calculating this is to set it to the weight of an object that would break the constraint if it were resting on its objects.
Torque Limit to Break (lbs * distance) `<float>`
Torque required to break the constraint, in pounds*inches. 0 means infinite. A way of calculating this is to multiply any reference mass by the resting distance (from the center of mass of the object) needed to break the constraint.
Play Sound on Break `<string>`
A sound played when the constraint is broken.
Follow teleport distance `<float>`
If one constrained object teleports more than this many units away, the other will teleport with it.

Targetname:

Name (targetname) `<string>`
The targetname that other entities refer to this entity by.
Entity Scripts (vscripts) `<scriptlist>` (New with Left 4 Dead 2)
Space delimited list of VScript files (without file extension) that are executed after all entities have spawned. The scripts are all executed in the same script scope, later ones overwriting any identical variables and functions.
Script think function (thinkfunction) `<string>` (New with Left 4 Dead 2)
Name of a function in this entity's script which will be called automatically every 100 milliseconds (ten times a second) for the duration of the script. It can be used to create timers or to simulate autonomous behavior. The return value (if present) will set the time until the next call.
Note:Try to avoid expensive operations in this function, as it may cause performance problems.

## Flags

• 1 : No Collision until break
• 2 : Keep Rigid
• 1: No Collision until break
• 4: Start inactive
• 8: Change mass to keep stable attachment to world
• 16: Do not connect entities until turned on

## Inputs

TwoObjectPhysics:

`Break`
Force the constraint to break.
`TurnOn`
Enable the constraint; do this if the constrained objects don't exist when it spawns. Note that broken constraints cannot be turned back on as they have been deleted.
`TurnOff`
Disable the constraint.

Targetname:

`Kill`
Removes this entity and any entities parented to it from the world.
`KillHierarchy`
Functions the same as `Kill`, although this entity and any entities parented to it are killed on the same frame, being marginally faster than `Kill`.
`AddOutput` `<string>`
Evaluates a keyvalue/output on this entity. It can be potentially very dangerous, use with care.
Format: `<key> <value>`
Format: `<output name> <targetname>:<inputname>:<parameter>:<delay>:<max times to fire, -1 means infinite>`
`FireUser1` to `FireUser4`
Fire the `OnUser` outputs; see User Inputs and Outputs.
`Use`  !FGD
Same as a player invoking +use; may not do anything. Can also be invoked by creating an output that does not specify an input.
This input is not included in Valve's FGDs.
`RunScriptFile` `<script>` (New with Left 4 Dead 2)
Execute a VScript file from disk, without file extension. The script contents are merged with the script scope of the receiving entity.
`RunScriptCode` `<string>` (New with Left 4 Dead 2)
Execute a string of VScript source code in the scope of the entity receiving the input. String quotation may be needed when fired via console.
Bug: In , the code is executed in the script scope of the entity that fires the output, not the one receiving the input.
Warning: Never try to pass string parameters to a script function with this input. It will corrupt the VMF structure because of the nested quotation marks, which then must be removed manually with a text editor.
`CallScriptFunction` `<string>` (New with Left 4 Dead 2) !FGD
Execute a VScript function in the scope of the receiving entity.
`SetLocalOrigin` `<coordinates>` (New with Alien Swarm) !FGD
Send this entity to a spot in the map. If the entity is parented to something, it will be offset from the parent by this amount.
`SetLocalAngles` `<angles>` (New with Alien Swarm) !FGD
Set this entity's angles.

## Outputs

TwoObjectPhysics:

`OnBreak`
Fired when the constraint breaks.

Targetname:

`OnUser1` to `OnUser4`
These Outputs each fire in response to the firing of the like-numbered `FireUser1` to `FireUser4` Input; see User Inputs and Outputs.
`OnKilled`  (Only in the Left 4 Dead series)
This Output fires when the entity is killed and removed from the game.