A Max UI external for spatial event detection and coordinate tracking.

bbox accepts coordinates from either mouse interaction or external data sources such as Jitter, OSC, OpenCV, MediaPipe, or custom tracking systems. It reports enter/exit events, continuous position tracking, and optional motion-analysis data from a rectangular region.

• Mouse-driven spatial interaction

• Coordinate-stream input via list x y

• Enter and exit detection

• Continuous position tracking

• Multiple coordinate spaces:

  • Local
  • Patcher
  • Screen

• Motion follower output:

  • Position
  • Velocity
  • Acceleration
  • Angle
  • Moving / Stopped detection

• Named send/receive integration

• Inspector support and help documentation

1. Install bbox.mxo into your Max Packages or search path.
2. Create a bbox object in a patch.
3. Unlock the patch and resize the object to define the active region.
4. Connect the outlets to your patch logic.

Outlet 0 outputs:

• 1 when a point enters the region
• 0 when a point exits the region

Outlet 1 outputs:

• x y coordinates of the tracked point

Outlet 2 outputs tagged follower messages:

• pos
• vel
• accel
• angle
• moving

bbox tracks the mouse cursor automatically.

Send coordinates directly:

[list x y]

Examples:

• Jitter blob tracking
• OSC tracking systems
• OpenCV
• MediaPipe
• Custom sensors

Select the coordinate system reported by outlet 1.

• Local
• Patcher
• Screen

When enabled, bbox continuously outputs while inside the region.

When disabled, bbox outputs only on enter/exit transitions.

Follower mode:

• Off
• Inside
• Both

Provides smoothed motion-analysis data on outlet 2.

bbox is built using the Cycling '74 Max SDK and CMake.

Build the project using Xcode or your preferred CMake workflow.

See:

• bbox.maxhelp
• Inspector descriptions
• Reference documentation included with the object

bbox is released under the MIT License.

Copyright (c) 2026 JD Clemon Lee Meredith