GPU being used in NVIDIA Iray preview, but not in rendering
kalina.pepa_29135cfc8e
Posts: 49
Hi, i have an issue, while rendering full render.. using render button, ,DAZ doesnt use the GPU, it only fills VRAM to, around 90% and use CPU... but when using NVIDIA Iray previw, it uses only GPU, the way it should be... GPU usage is around 10%, and yes, i have the GPU checked in Advanced render settings.... no info or crashing due to inssufficient VRAM or anything,.. so no clue whats wrong
Is there a reason, why it doesnt render using GPU, as it should, same as during the preview render?
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Comments
Is it possible that it has to do with SubD?
Usually the SubD used for rendering is one higher than the SubD used in the IRAY preview. Perhaps that put it over the limit of your card?
Decrease SubD of your character(s) by one and see if it helps.
That makes 0 difference... i wonder whats wrong... i did put all down to 1 on Subd and no change, only like 500 MB less of ram , but thats it
Maybe try to attach a log file so people can look into whar it says.
SubD isn't the only difference between the preview Drawstyle and an actual render - displacement, for example, is not used in the drawstyle which will probably reduce the number of maps sent across.
The info is in the log (Edit->Troubleshooting->View Log File)
Attach the log file to your post and we can have a look (do not copy the text into the message area)
Richard Haseltine I always see you telling people that displacement does not show in the Iray preview and it's not true.
kalina.pepa_29135cfc8e Probably it's because the dimensions of your render are much larger than the dimensions of your viewport.
I admit I was being prompted there and didn't check, but it certainly used to be the case - by default - that displacement was not used (though I could be enabled). However, even the Interactive preview mode is now showing displacement, as you say. However, it does not use the Render Division Level so it will not usually be an accurate representation of the rendered result
Richard Haseltine Are you talking about the Displacement Subdivision? Because it shows that too.
When I tested it was clearly not using the Render SubD level but the base SubDivision Level.
Richard Haseltine I'm sure you know that there is an additional Displacement SubD level setting when displacement is active. There is definitely some interaction between the Figure or object subD and the Displacement SubD, and also the pixel resolution of the maps. I've noticed that without turning up the Displacement Subd that often displacement doesn't seem to work at all or just randomly distorts the object.
It sounds like maybe this is not how it always was, but it's been my experience since I started messing with displacement a lot several years ago. I often place figures sitting, standing, or leaning on displaced surfaces, and I use the iray preview to line them up properly.
I attach three images of a one division plane, covnerted to SubD, with a random map applied to SubD Strength and the bounds set to +/-2.5 - they differ in their division levels, set in the Mesh Resolution group, as noted in the filename. I think it is clear which settings is having an effect on the preview DrawStyle
Now I'm not sure what point you're trying to make. You seem to have missed some words or maybe even mislabeled something.
A plane with only one division will not show displacement correctly unless you turn the displacement subD up quite a bit. That same plane subdivided a bunch (my slider goes up to 9) will show displacement pretty well even without turning displacement subD up at all. A plane with many divisions will also show displacement well even at base resolution, and without displacement subD turned up. Displacement doeas not seem to care if the divisions are real (in the base geometry) or if they are virtual subdivisions. I've found that it also matters quite a bit how high resolution the displacement map is.
I have never noticed any differnce between the iray viewport and the actual render in regards to displacement, but that may be because I'm using surfaces with lots of divisions and turning up the displacement subD pretty high along with high res displacement maps.
My point is that the Drawstyle does, as you corrected me, show displacement it uses a different value to determine how many divisdions to apply (to a SubD model, which characters are) and so the results will not, by default, match a full render - and will not, by default, consume as much memory.
I always set my preview and render subD to the same, whether I'm using displacement or not. That's probably why I wasn't understanding. I'm sorry if I seemed argumentative. I was really hoping that you knew something that I don't, so I could learn. Now that I understand, I think I have learned something. Thanks!
You're welcome, and you were right to call me out on saying displacement didn't work at all in the Drawstyle so thank you for that.