In version 3 or later, once V-Ray has been selected as the rendering engine, everything is ready for you to launch a render. There’s no need to enable or disable anything to get an immediate preview of what you are building in the viewport .
When we click on Render, the precalculation of the indirect secondary light starts immediately with Light Cache and then the rendering of the whole image begins in progressive mode for a maximum time of 1 minute. The settings shown in Figure 3-4 and Figure 3-5 control this calculation by default.
V-Ray default sampling settings, showing the Render time, which by default is set to 1 minute
V-Ray default settings for calculating the Global illumination
Until V-Ray version 3.2, the Irradiance Map / Light Cache (IM+LC) combination was generally preferred for its quality-speed ratio. However, from version 3.4 onwards, and particularly with the latest version V-Ray NEXT , the Brute Force algorithm has improved dramatically.
For this reason, we’ll always be working with the default setting (BF + LC) while addressing the theme of photography.