$collisionmodel

$collisionmodel is a QC command available in all Source games.

It is used to embed a static collision mesh in a model for use in VPhysics calculations. Animated models (including ones that will become ragdolls) should use $collisionjoints instead.

Warning:Collision meshes should have extremely few polygons. See Collision mesh for examples.

Note:For collision meshes modeled in Blender or Softimage Mod Tool, ensure that none of the edges are marked as hard/sharp. Hard/sharp edges generate errors in the physbox model.

Tip:Set the Console Variable vcollide_wireframe 1 to view collision meshes in-game.

Syntax

$collisionmodel	<collision mesh SMD/DMX>
{
	<options>
}

Options

Stub

This article or section is a stub. You can help by expanding it.

Note: Missing parameters for some options

kilograms>

Manually set the mass of the model, in kilograms.

Tip:By default, the Player can +USE pick up 35KG max. The gravgun can pick up 250KG max. The portal gun can pick up 85KG max.

$automass

Calculate the mass of the model based on the volume of the collision model and the material defined in its prop_data.

$concave

By default, studiomdl will generate a single convex hull by 'shrinkwrapping' any concavities. You can create a concave hull by including multiple convex shapes (potentially overlapping) in your collision model, smoothing the hulls’ shading, and passing this command.

$maxconvexpieces <int> (in all games since )

By default, the model compiler limits a concave collision model to twenty convex pieces. This command can be used to override the limit if you are creating a Costly collision model.

Note:Introduced with the Orange Box. In the Ep1 engine, run studiomdl with -fullcollide instead.

Warning:Going past a hundred or so pieces may begin to create server lag when multiple objects are touching the model.

offset>

Override the center of mass, in local coords.

$inertia <normal>

Inertia scale. Higher values will make the physics object more sturdy, while lower values will make it more wobbly.

$damping <float>

Linear damping scale. Affects how quickly an object's velocity drops to zero.

$rotdamping <float>

Rotational damping scale. Affects how quickly an object's angular velocity drops to zero.

Warning:This affects the pull of gravity on the model and if abused can make it appear to float gently through the air. Valve recommends using "friction" instead.

$drag <normal>

Scales air resistance. Essentially a more subtle version of $damping.

$jointskip

Rarely used. Eliminates a joint in the collision model that you don't want to use. (i.e. if you were using a render model as a ragdoll, and it has bones you don't want).

$jointmerge

Merges the vertex assignments for two joints.

$jointinertia

Like $inertia, but per-bone.

$jointdamping

Like $damping, but per-bone.

$jointmassbias

Mass is automatically distributed by volume, this lets you bias it per-bone.

$jointrotdamping

Like $rotdamping, but per-bone.

$jointcollide

If any $jointcollide pairs are specified, only those joints collide with each other.

$jointconstrain

The limits of the joint's movement.

$rootbone

The parent-most bone that actually has collision geometry.

$noselfcollisions

Turns off all collisions between bones in this model.

$animatedfriction

Used to animate the amount of friction on joints over time.

$addconvexsrc <file> "offset pos[ <float> <float> <float> ] angle[ <float> <float> <float> ] scale[ <float> ] concave" (only in )

Adds a convex model onto the collision model with the specified position, angle, and scale. The "concave" option is optional.

Note:It must be formatted EXACTLY like this!

$remove2d

Used to remove flat shaded faces. Off by default.

$weldposition <float>

The amount of distance tolerance to use when trying to merge vertices of separate concave pieces in order to create a single concave piece.

$weldnormal <float>

The amount of tolerance to check if the vertice normal is similar enough to consider merging to a unique vertice. Used in conjunction with $weldposition.

$assumeworldspace

Assumes the joints are positioned in world space.

Example

$collisionmodel "tree_deciduous_01a_physbox"
{
	$mass 350.0
	$concave
}

See also

• Collision mesh
• $collisionjoints
• Costly collision model
• VPhysics
• Physics and Ragdolls