View Full Version : Mental Ray help request (images provided)
04-15-2008, 03:10 PM
Anyone have time to look over my settings and offer some advice? I need photorealism.
single spot light settings:
04-15-2008, 03:52 PM
Mental Ray settings:
04-15-2008, 05:02 PM
here is the maya scene file if anyone has the time to check it out. ver. 8.5.
RIGHT CLICK AND SAVE (http://davezak.com/webposting/mentalray_test2.mb)
04-16-2008, 12:56 AM
On your lights, use Raytrace Shadows instead of depth-map shadows. Depth shadows will always be grainier, even at high settings, and won't transmit accurately through transparent, refractive objects.
In the mental ray globals, your Photon Volume Accuracy is set to 30. For smooth results, set it equal to your GI accuracy, then tone both down after a few test-renders until it's acceptably smooth.
Also it could be due to .jpg compression or resizing, but your Anti-Aliasing settings should be set to "Custom", and at least 0 and 2.
If you still need help I'll download the scene and give it a shot, but try those things first and see if you can reach a more acceptable quality?
04-16-2008, 01:17 AM
Lordstormdragon, thanks, I will make those adjustments tomorrow.
04-16-2008, 09:33 PM
The above images have been swapped to show the newest renders.
My render time is now VERY low (under a minute). I do have a powerful mac here, but almost WANT renders to take longer and look wicked. I stopped using IBL or physical sun, and got rid of caustics.
If anyone has a moment, please check over my settings and tell me what is am missing.
again, I want to achieve photorealism. Every day is one step closer. hmf.
04-16-2008, 09:45 PM
Switch Final Gather to point interpolation, up to 64. Also, the Final Gather scale looks lower than 1, it's more workable around 4. Reduce the brightness of your lights by half and this will even out the lighting.
Switch to raytrace shadows with 8 rays, radius of 2 for soft shadows. Depth shadows are causing a great deal of graininess.
Your raytrace depths are all too low. Max Trace won't do any good set to 2 with everything else set to 1. Set reflections to 4 at least...
Photon Volume Accuracy should match GI accuracy (200 in this case) for more accurate photon.
04-18-2008, 05:33 PM
...obviously didn't include the IBL image, but I don't think that was your issue.
First thing, your antialiasing settings were set to 0. This will produce jagged lines and edges and also make textures appear grainy or jagged. I set it to "custom" from 0-2, then from 2-4.
Also, I made all the changes I mentioned in your globals and it rendered much faster and much cleaner. I could email you the changed file, which will likely pick up your file nodes automatically, and you could give it a shot from your end?
For example, the Final Gather accuracy was set to 2,000. This made little or no visible difference but increased render times vastly. Same with your GI accuracy: it doesn't need to be set to 500, although I can see why you tried it that high. The photon volume was still set to 30 and auto-volume was off... I set all GI and FG accuracies to 100, then to 256 to see how much difference it makes during rendertimes. I also set FG to NOT use Radius control, but point interpolation set to 32 and density at 1. This will smooth it out a bit, at the cost of slightly longer render times.
And lastly, your GI and FG scale was set really low, I cranked that up to 2 on each to brighten things up a bit. This might overexpose your IBL node a bit, but you can just turn that down in the image options...
Here are my test renders:
Render 1 - your Antialiasing settings, FG 100, GI/Photon Accuracy both 100, time 3:41:
Render 2 - AA set to 0/2, FG 100, GI/Photons 100, FG/GI scale set to 2, time 4:18:
Render 3 - AA set to 2/4, time: 11:11:
Render 4 - FG/GI/Photon accuracy set to 245, time 20:15:
As you can see, the third one is the best balance of quality vs. time. Increasing the accuracy of the GI and FG didn't help much, so 100 for all accuracies worked fine at this resolution. The main thing was your antialiasing settings.
Changing your photon attributes might also help, but I'll leave that up to you for now. I'd personally leave out the ambient light and just use GI/FG, and turn on sky photons (which weren't on in the file you sent me).
04-18-2008, 06:22 PM
wow thats alot of work.
last night i did the changes from you previous advice. I dug a hole for myself and then started from scratch hoping that I had learned a lot in this process. results are getting better.
You spent plenty of time on this. thank you very much.
my email is firstname.lastname@example.org (or email@example.com), I would love the maya file with your settings.
Include your address in the email I'd like to send a thanks.
04-18-2008, 06:22 PM
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