Collider

../../../../_images/ui_comp_coll_body.png

A primitive-shape collider attached to the object.
Unlike a Collision-Mesh this uses a simple analytic shape,
which is cheap and suitable for moving/dynamic objects.
Pair it with a Rigid-Body for full physics simulation.

Options

Option

Description

Type

The collider shape:
• Box
• Sphere
• Cylinder
• Capsule
• Cone
• Pyramid

Shape size

The dimensions for the chosen shape in meters, e.g. Half Size for a box, Radius for a sphere, or Radius plus Half Height for cylinders/capsules/cones. Scaled by the object’s scale.

Offset

Offset of the shape’s center relative to the object’s origin, in meters. Scaled by the object’s scale.

Trigger

When enabled, the collider reports overlaps as events but produces no physical (push-back) response.

Reacts to

The collision layers this body reads (which layers it collides with).

Is Affecting

The collision layers this body writes (which layers see it).

Friction

Surface friction, 0 to 1.

Bounce

Restitution / bounciness, 0 to 1.

Changing a collider at runtime

Every value on this page is set on the collider itself, the component only creates it and registers it with the collision scene:

auto &coll = obj.getComponent<Comp::CollBody>()->collider;

auto halfExtend = coll.halfExtend();
halfExtend.y += 0.5f;                        // e.g. the half height of a cylinder/capsule/cone
coll.setHalfExtend(halfExtend);

coll.setCylinderShape(0.5f, 2.0f);           // size and shape type in one go
coll.setShapeType(Coll::ShapeType::Capsule); // keeps the size, folds it into the new shape
coll.setParentOffset({0.0f, 1.0f, 0.0f});    // moves the shape's center

Sizes and offsets are in the object’s local space, exactly like the values in the editor: the object scale is applied on top of them and stays applied when the object is scaled later on. The object-scaled result the collision detection runs on is read-only and named world..., e.g. P64::Coll::Collider’s worldCylinderShape() or worldAabb().

setHalfExtend() works for every shape. Shapes that don’t use all three axes fold them in, e.g. a cylinder takes its radius from max(x, z) and its half height from y, and a sphere takes its radius from the largest component.

All setters keep the AABB (and with it the broadphase) plus the mass properties of an attached Rigid-Body in sync, and wake up sleeping bodies the change may touch. That is why the dimensions cannot be written directly.

See also