phys_constraint

Source Engine

Source 2

Class hierarchy
CPhysFixed ↳CPhysConstraint ↳CLogicalEntity ↳CServerOnlyEntity ↳CBaseEntity
physconstraint.cpp

phys_constraint is a point entity available in all Source games. It forces one entity to keep its position in relation to another. The two objects need not be touching, or even near to each other.

If a phys_constraint is attached to a func_train, it will not hold. Instead, parent a func_brush to the train and attach the phys_constraint to that.

Keyvalues

TwoObjectPhysics:

Entity 1 (attach1) <targetname>

Entity 2 (attach2) <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 (constraintsystem) <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 (forcelimit) <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 (torquelimit) <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 (breaksound) <string>

A sound played when the constraint is broken.

Follow teleport distance (teleportfollowdistance) <float>

If one constrained object teleports more than this many units away, the other will teleport with it.

Name (targetname) <string>

The name that other entities refer to this entity by, via Inputs/Outputs or other keyvalues (e.g. parentname or target).
Also displayed in Hammer's 2D views and Entity Report.

See also:  Generic Keyvalues, Inputs and Outputs available to all entities

Flags

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

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.

Outputs

TwoObjectPhysics:

OnBreak

Fired when the constraint breaks.