Prop physics

Entity Description

A prop_physics is an entity which, when placed in a map and set with a model, creates a physics object. Physics objects can be picked up with the grav gun, according to their weight, and fully interact with their world in terms of collision, gravity, and world effects. If you have played a source game in any form you have definitely seen one in action. Additional settings in the entity include a multiplayer for weight, name field for I/O interactions, damage type (sharp or blunt), etc. Entities can be flagged to start motion disabled (think saw-blades), and additionally flagged to allow or disallow gravity gun pickup, etc.

If you are creating a multiplayer map, you should use a prop_physics_multiplayer for most objects instead of a prop_physics. Prop_physics is ideal for single-player maps, where accuracy of interactions has no network overhead to worry about. The detail going into the interaction between objects in multiplayer results in an undesirably large network overhead and thus requires the detail of the interactive aspects of the objects be simplified. To solve this, Valve created prop_physics_multiplayer, which uses a much simpler structure of the model to do physics interactions, resulting in much better network play. Extremely simple models (simple being anything "boxy" [computer cases, keyboards, small jars, etc.]) will not have prop_physics_multiplayer settings, but this is fine because those models are so simple that making them prop_physics will not have an adverse effect on network traffic. If you are having a problem in a multiplayer map with a small object that is behaving strongly as a prop_physics_multiplayer, try making it a prop_physics.

Valve has tried hard to keep you from having to reinvent the chair every time you want a chair in your map. Models have built in properties that set the material, health, and sounds associated with an object. If you are dissatisfied with the built in properties, use a prop_physics_override to gain more control over the object's properties. I have yet to require the use of this yet, so someone with more understanding of where this should be used than myself should clean this up.

If you are making a multiplayer map and want your breakable objects to come back after a while, use a prop_physics_respawnable.

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See Also

List of entities

Overview of Prop Types