Conventions Reference

This section provides a reference for the units, representations, and coordinate conventions used within Omniverse Isaac Sim.

Default Units

Measurement

Units

Notes

Length

Meter

Mass

Kilogram

Time

Seconds

Physics Time-Step

Seconds

Configurable by User. Default is 1/60.

Force

Newton

Frequency

Hertz

Default Rotation Representations

Quaternions

API

Representation

Isaac Sim Core

(QW, QX, QY, QZ)

USD

(QW, QX, QY, QZ)

PhysX

(QX, QY, QZ, QW)

Dynamic Control

(QX, QY, QZ, QW)

Angles

API

Representation

Isaac Sim Core

Radians

USD

Degrees

PhysX

Radians

Dynamic Control

Radians

Matrix Order

API

Representation

Isaac Sim Core

Row Major

USD

Row Major

World Axes

Omniverse Isaac Sim follows the right-handed coordinate conventions.

../_images/isaac_conventions_world_frame.png

Direction

Axis

Notes

Up

+Z

Forward

+X

Default Camera Axes

../_images/isaac_conventions_camera_frame.png

Direction

Axis

Notes

Up

+Y

Forward

-Z

Note

Isaac Sim to ROS Conversion: To convert from Isaac Sim Camera Coordinates to ROS Camera Coordinates, rotate 180 degrees about the X-Axis.

Image Frames (Synthetic Data)

Coordinate

Corner

(0,0)

Top Left