About 

The ProjectionBuddy is used to project 2D images into World Position, or PRef data, without the need for geo exports. Useful for replacing screens/textures, adding gobo shapes, creating masks that are very complex, and caustics. It has a built in preview and calibration feature to help you project your images easier, and edge cleanup within one tool

You can read the full documentation for the ProjectionBuddy here

 Features 

Press and hold Ctrl+Alt while using the Position sampler on the preview image, to project 2D elements anywhere in your scene

Use the Calibration Image to help position and choose the proper orientation for your projection

Project images to create complex masks and textures

 The Buddy System 

This is a suite of tools I've been working on, which is designed to help compositors of all skill levels accomplish fundamental tasks, quickly and intuitively

If you'd like to learn about the other Buddy System tools you can find them here, and feel free to reach out if there are any issues, or if you have ideas to improve them!