Hey I’m pretty new to RT and just trying to test it out and get it working. For some reason it seems to work fine in cpu mode but as soon as I switch to cuda… it just sits there doing nothing. Doesn’t render. Any idea why this might be? And how to fix?
the vray messages window just says “waiting for image data”
I would have imagined a titan black would be a bit more snappy 
R.
Are you running by any chance V-Ray as a service (Windows does not allow apps to use GPUs when they are started in service mode) ?
If not, have you try turning it off and on again to see if that helps ?
Doest this happens to empty (or very simple) scene also ?
A bit more info about OS, V-Ray version, host app (Max, Maya, etc) may help too
vray is a service yeah. Turning it off and on again seemed to do nothing (unless I need to quit and restart max too? Or some other combination of events I’m not considering)
happens in a simple scene with a few spheres and a vray light
win 7. max 2014. vray 3.10.03. Titan black/nvidia driver 344.80
puter is a Falcon northwest fragbox i7-4930 3.40ghz/32GB ram
RT GPU won’t run when V-Ray is started as a service. This limitation is not caused by V-Ray. Windows will not let services using the GPUs.
You have the start V-Ray as an ordinary process.
I’m having this same issue with an NVidia K5200. In CPU mode it RT works fine, but in OpenCL or CUDA it says “waiting for image data…” forever and never updates or starts.
Do you have your V-Ray running as a service ? If so, please start is as a normal process - Windows services have no access to the GPUs.
If not, can you show the log of the vray.exe process ?
Yes, that seemed to do it. I had to do it three times and reboot each time to get it to take. I did it one time and then posted. I did it two more times just now and it seems to have corrected the problem. Thanks for the extra nudge. I should know better than to just try a solution once. I need to remember to try it 3 or 4 times before I determine it’s not a solution.
Glad that it works now