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All the VR/archvis stuff out there is fast, no doubt. Many of those tools use physically-based light transport algorithms as well. The problem is that none of them return real lighting values which could be interpreted in terms of glare or passed to an existing or proposed glare metric -- assuming that "glare" is easily determined from a single output (which it is not). While they are useful and efficient at producing images that look "good", the images are somewhat useless for quantitative analysis.

In your post, you imply this is a non-issue, because designers could "experience" the space, and lighting effects, first hand. The problem here is that to truly "experience" glare, one would have to have an HDR VR display, and these are a) only now becoming available, and b) would still need valid HDR input (not to mention some validation). Guess where that valid HDR input might come from? That's right, Radiance (or derivative work such as Diva). This is saying nothing about the fact that glare is highly subjective and so if left to the conclusion of (n) member(s) of the design team, who's to say the design "works", or is "glare free"?

Your comment about the requirement for "even more time" (on the part of the "designers") to understand the glare analyses sounds a lot like you wanting to eliminate the role of the lighting consultant altogether, which is fine and nothing new, but it loses sight of the very real need for the lighting consultant's intuition, industry experience, and passion. Any tool in the wrong hands is ineffective at best, and more likely dangerous. Lighting consultants are often needed to interpret the output from lighting design tools in much the same way the architects must interpret the plans, sections, and elevations for their clients. Unfortunately, architects continue to lose sight of this simple truth.