They Googled furiously: "vray light gen not working" — and found forum threads from 2018, vague mentions of "paths," and a buried comment about "Windows usernames with spaces."
Alex thought, "No problem. I'll use V-Ray Light Gen. Click a preset. Done." vray light gen not working
They selected the dome, chose "Sunset," and hit . They Googled furiously: "vray light gen not working"
The fix? Change the to a simple path like C:\VRayTemp (no spaces). Or, in newer versions, update to the latest hotfix. Or, in newer versions, update to the latest hotfix
That was it.
V-Ray Light Gen, in some versions, fails to write temporary HDRI preview files to a path containing a space. It silently fails. No error. Just a dead, dark dome.
It was 2 AM. Alex had a villa exterior due in 12 hours. The client wanted "dramatic, cinematic sunset lighting."