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Dimensions and scalar precision

Rapier's Python bindings ship as four independent PyPI packages, one per (dim, scalar) flavor. They share an identical API differing only in dimension and scalar type:

PyPI package import name dim scalar
rapier3d rapier3d 3 f32
rapier3d-f64 rapier3d_f64 3 f64
rapier2d rapier2d 2 f32
rapier2d-f64 rapier2d_f64 2 f64

Install only the flavor(s) you need (pip install rapier3d). rapier3d is the canonical reference these docs are written against, matching use rapier3d::prelude::* in Rust.

Recommended import patterns

# The common case: 3D, single precision.
import rapier3d as rp

# 2D, single precision.
import rapier2d as rp

# 3D, double precision.
import rapier3d_f64 as rp

# 2D, double precision.
import rapier2d_f64 as rp

The Python API surface is identical across (dim, scalar) modulo dim-specific types:

  • Vec2 / Point2 / Rotation2 / Isometry2 versus Vec3 / Point3 / Rotation3 / Quaternion / Isometry3.
  • SphericalJoint and the ray-cast vehicle controller are 3D-only.
  • Cylinder, Cone, and ConvexPolyhedron are 3D-only shapes; Segment, Polyline, and ConvexPolygon are 2D-only.
  • Angular quantities (angular velocity, torque) are a plain float in 2D — there is no AngVector2 type. In 3D, AngVector3 is an alias for :class:`~rapier3d.Vec3`.

Choosing a precision

Single precision (f32) is the default and is what the rest of the Rapier ecosystem ships. It's the right answer for almost all use cases — games, robotics simulation, and physics-based animation.

Double precision (f64) is available for cases that require it: large worlds where coordinates exceed ~1e5 metres, long-running deterministic simulations where round-off drift matters, or comparisons against reference solutions computed in f64.

The two flavors have separate cdylibs and separate types — instances do not interoperate. Vec3(1, 2, 3) from rapier3d is a different class from Vec3(1, 2, 3) from rapier3d_f64.

Snapshot blobs are not tagged with their flavor: always restore a snapshot through the same (dim, scalar) flavor that produced it, otherwise the floats will be silently misinterpreted.