Relight allows you to create infinite images from a single render. When Relight is enabled, every light in the scene can then be modified (intensity, color and status) and create different lighting setups in post production.
Every Relight setup can be saved in the Relight Editor panel as a Snap and then loaded back to the Darkroom for further editing or exported to an image file.
If you want to learn more about Relight, have a look at this video.
Relight is supported by Presto (Production Mode only), and Unbiased TR1/TR2
The Relight Editor tab can be found in the Settings Panel. After the completion of the rendering, you can find all the lights of the scene in the editor.
(1) Snapshot: Click this button to create a snapshot of the current Relight settings. A new thumbnail will be created at the bottom of the editor
(2) Reset: Resets all the controls and values back to the default ones.
(3) Enable/Disable All: Click this button to enable or disable all the lights in the scene at once.
(4) Enable/Disable Light: Turns on/off the selected light.
(5) Solo: Isolates the current light.
(6) Name: Displays the name of the light / light group.
(7) Intensity: The intensity of the light
(8) Color: The color of the light.
Learn more about how Thea Render groups light based on the scene setup in this video.