OpenGL renderer

This is the default built-in rendering engine, which is also used by OVITO for rendering the interactive viewports.

The “More Options” (vertical ellipsis) button next to each nummerical parameter opens a context menu with the option to reset each paramter to its default value.

Parameters

Anti-aliasing level: To reduce aliasing effects, the output image is usually rendered at a higher resolution than the final image (supersampling). This factor controls how much larger this resolution is. A factor of 1 turns anti-aliasing off. Higher values lead to better quality.
Transparency rendering method: Selects the method for rendering semi-transparent objects when they overlap with each other. See the viewport settings for more information on the available options.