(1) Start/Pause: Starts rendering in the Darkroom. Once render has been initiated, this button is used to pause the current render.
(2) Stop: Stops the current render. During batch rendering, the stop button will cancel any batches in the queue.
(3) Open Image: Opens an .img.thea image for editing.
(4) Save Image: Saves the image of the last render that was initiated.
(5) Render Mode: Selects the render mode for the next render. IR: Use Interactive Rendering | PR: Use Production Rendering.
(6) Render Engine: Select the render engine for the next render. Depending on the render mode selected, only the available render engine can be selected.
(7) Termination Criteria: Sample Limit defines the samples per pixel to be reached before the render finishes. Time Limit defines the time limit in minutes to be reached before the rendering finishes.
(8) Channels List: Select the render channel to be displayed on the render panel. A channel needs to be activated in the Channels Tab, before render begins.
(9) Pick Camera Focus: Select the point to which the camera will focus during Interactive Rendering. Shortcut: CTRL+LMB
(10) Pick Material: Allows picking an object's material during Interactive Rendering. Shortcut: ALT+LMB
(11) Region Render: Click and drag a rectangle region in the render panel and render only the specified region of the image.
(12) Lock Viewport: Select this option to lock Interactive Rendering in Thea Darkroom to the active Viewport. Once Interactive Rendering starts with this option enabled (locked), changing Rhino viewports will not affect the active sesion.