This is the historical format used by older V-Ray versions. It contains all the options for the current scene, including the render engine, quality, and global illumination (GI) settings. A .visopt file is typically very lightweight, often around 2KB.
Achieving photorealistic architectural visualizations in SketchUp requires a deep understanding of V-Ray’s complex rendering engine. Adjusting global illumination, sampling, and light bounce settings manually for every project is incredibly time-consuming. Using pre-configured render settings files (VROPT files) can drastically accelerate your workflow, providing a shortcut to professional-grade outputs. The Value of V-Ray Render Settings Files (VROPT) sketchup vray render settings file download
Interiors (day or artificial):