The VRayLightingAnalysis render element is a post-effect and is only updated once the rendering is complete. After the render is complete, most VRayLightingAnalysis settings can be adjusted without having to rerender. Simply change the setting and press the Update button.
When using the same settings (min/ max and scale type) as the VRayLightMeter, the results should be the same for the total illuminance.
Illuminance values shown over glass and mirror objects represent the illuminance on its surface, not the surfaces that are seen through the glass or in the mirror. Because these materials do not reflect light diffusely, V-Ray computes these illuminance values with very low precision — or it may even skip the illuminance calculations completely. Therefore, these values may be quite noisy or even zero.
To ensure correct results, it’s recommended to use the default V-Ray GI settings, with increased light cache subdivs (e.g. 2000) and a higher light cache retrace threshold (e.g. 4.0).
Converting previous 3ds Max lighting analysis scenes
There are two ways to convert your existing 3ds Max scenes and lighting analysis components to V-Ray equivalents. One method is using the 3ds Max Scene Converter tool. The other method is to use the V-Ray scene converter script that’s included with V-Ray Next. Both tools can convert 3ds Max Light Meter objects and Lighting Analysis Overlay render effects, as well as other scene components, into their respective V-Ray equivalents. To select the V-Ray scene converter, right-click in any 3ds Max viewport. (Make sure V-Ray is set as the current renderer.)