I have a LWF scene that is taking very long to render and is very noisy at 720p. I added a whole bunch of RenderElements to get to the bottom of it. So almost all the elements are nice and smooth Except for the VRayReflection and VRayShadow elements. The VRayReflection Element is VERY noisy. Whats’ the best route to clean it up? Simply add more subdivs in the reflection part of the materials? Or is there another way with maybe dmc and dmc sampler to do it?
My current settings:
reflection subdivs on materials vary between 16 and 64 (which is already high)
Scene lit with only 3 cove lights with VRayLightMTL multiplier 3, compensate camera exposure ticked, direct illum ON and 128 subdivs
Adaptice DMC: 2, 32, 0.005 thresh UNTICKED
IRMap: Medium Preset with HS subdivs 50 and Inter samples 40. Detail Enhancement on and Check sample visibility ticked
Light cache 1000, 0,02, prefilter ticked on 10, interp samples 10, use light cache for glossy rays TICKED
DMC Sampler: adaptive 1 thershold 0.005
It takes 4 X i7 pc’s 2 hours to render 1 frame with DR at 720p!!!
Any hints?
GI Element has very minor minute noise hardly visible
EDIT: Max 2012 scene file dmc.zip attached a bit further down in this thread at post no 8
EDIT2: Max 2011 scene file just 2 posts below that at post no 10
it’s most of the objects as all objects have glossy reflection.
Main one however is default VRayMTL with diffuse 200,200,200
white reflection fresnel ticked
glossy 0.85
64 subdivs
ok so I’ve switched from IRMap to Brute force and put subdivs to 256 and also on my material reflection put 256 subdivs for reflection and glossy 0.625. For DMC changed to 2,6
NO noticable change!
Anynody have any thoughts?
This is is zoomed to 200%
You can also notice some noise on my metal shopfront frames
afaik, if you need 32 as max for adaptive dmc you have to raise mat & lights subd a lot more then 64 or 128 (I’ll say 256 and raise clr threshold to 0,01 or more) because right now you are leaving all the job to be done by image sampler (that in 2.0, for me, is slower then in 1.5)
hope it helps
while gi has minor noise, it contributes to render time, detail enhancement is brute force with a radius. Check this render out. Its all brute force/lc with glossy reflections/refractions. All in all render time is 2.06 on my 12 core xeon.
ok here is a simplified version of my scene above. After 40 min of render, this is all that is rendered, its estimated another 3 hours to go. And it has LOTS OF NOISE!
What can be done to clean up the noise and also speed up render times with brute force?
And also,
here is the max file:
It’s a max 2012 file with VRay 2 latest stable public version.
This simplified scene has most of the major materials from current bigger scene.
hmmm ok, so I’ve changed to following:
in the main material in options I changed cutoff from 0.01 to 0.001 and also I’ve set “treat glossy rays as GI” to ALWAYS instead of “only for GI rays”
and now its rendering about 75% FASTER. It’s still dog slow I think. Took 1 hour 29 minutes on my machine.
ALSO
I tried switching to reinhard with burn of 0.5 and “adaptation only” unticked instead of full LWF and also it rendered FASTER with a time of 54 minutes total. Also for reinhard I needed to bring the exposure down with a smaller value to get a nice range (-0.7) and with linear I needed to bring it down by as much as -3.6!
So I’m geussing then if I just expose properly using linear, theoretically I should get same render times as with reinhard.
I would like to however clean the image up some more AND bring the render times down even further.
Any thoughts?
I had a quick look at your scene. I would not recommend using direct lighting from vray light material, it will only make the image more noisy. You also have amb occlusion checked, it will make it also slower and look wrong in terms of gi.
ok then would you say use vray light in “mesh” mode and select my cove lighting that currently has the vraylightmtl on it?
would u then do a seperate dirt pass for the AO or how?
My understanding is that its a clean interior, why would you need a dirt pass? Dirt/ao gives unnatural darkening in areas you normally would not have.
For the lighting i would not use mesh light either. Mesh lights produce more grain then regular lights. In this case, you are better off just using gi in that area from light mtl.
In terms of render time, any time you render with bruteforce expect your time to be high.
For fast render time you got irradience map (obviously not as good).
I will show you a diff setup when im home later today.
playing with your file I’m just going in the same direction Dmitry suggested
till now, IMHO the main grain generators are:
- vrlightmtl with direct checked: do you really need it? …from my test I’ll say a big no, go with GI only
- ao pass: that one it’s easier, just raise subds a bit
IMHO I’ll switch to IR/LC + AO (with extra text could be better); it’s a fake but it’s faster; at the end the final decision will be based on the real complexity of the scene (if your renderfarm could afford long render time then go with brute forcr, otherwise stay with IR/LC
Thanks I look forward to your setup. As for the ligthmtl, I’m using direct light option as in the past I had splotches by not using it. The direct light fixed this, but ok that was a while back so things may have changed, I’ll try without “direct light” option in light mtl. So you saying I shouldn’t use AO as Brute Force already produces correct contact shadows?
I’m hoping to permanently switch to Brute force so want to fully understand how it works. Also see the comments and questions I replied to Morbid Angel’s response. Upping the subdivs in the AO is something I will try, but if Brute force already gives me the contact shadows etc then I geuss I dont need the built in fake AO or the extra text? I’ve never used extra text so not sure how to make use of it.
UPDATE:
In the meantime I’ve changed the multiplier from my “camera flash” hehehe (the vray light behind the camera) from 30 to 45. I changed the vraylightmtl multiplier down to 3 (but considering putting it even further down to 1). I’ve changed camera exposure shutter to 225 and iso 200. I brought DOWN brute force subdvis from 64, down to 16. Strangely bringing down brute force subs didn’t effect the noise much and it looks almost a little less noisy (maybe due to the other settings I’ve changed that I mentioned)
AND
render times so far is DOWN from 1 hour 29 minutes, down to 28 minutes. So now just to clean the noise it seems. In the GI render element there is more noise however, but in beauty pass it looks slightly cleaner than before.
So to clean the beauty pass what do you suggest? maybe this:
- INCREASE material subdivs
- remove direct light from vraylightmtl
- decrease dmc and sampler from 0.005 down to 0.003
?
Your thoughts?
P.S. Most of the interior scenes I do nowadays consist of places being lit mostly by CURVED COVE lighting, that’s why I use VRayLightmtl. It takes too long to devide a 50 meter curve into a hundred 500mmX40mm vraylights especially if the curve isnt a normal curve, but some irratic curve going all over the place. Then there are also mutli level cove lights sometimes up to 4 or 5 steps one above another (not in this scene however)
main changes without touching the core of the scene (mtl glossiness, lights intensity and position etc.)
- totally reset vray importing geometry, lights and camera in a new scene (I had issues with your file, I don’t know why)
- lightmtl without direct light (only GI)
- ao subds raised
- various mtl subds raised
- global subds raised
- new image sampler set up
- clamp output and subpixel mapping checked
- “flash light” is now visible in specular and reflection (I like it more)
there are still problems with the glossiness of glass panels on the left, maybe tomorrow I’ll double check them
sorry, no brute force but IM/LC
a quick note about cove lights, just remember that in general they are mainly decorative; in real life it’s very hard to light a space in a good way only using that kind of fixture
Thanks, lets also see what Morbid Angel comes up with. I’m still hoping to get to the bottom of Brute Force inner workings and avoid clamp output and subpixel mapping. Doesn’t it defeat the purpose of using LWF?
On a side note, how is the VRaySampleRate Element useful? I’m guessing the main idea is to a get a blueish image? I remember on my main large scene (the 1st image I posted in this thread) that there were a LOT of red parts in the samplerate element and I’m geussing that’s bad?
@zeronove: I’ll take a look at the scene you modified when I get to work tomorrow…
In theory yes, actually no if you are not planning an hard postprocess stage.
one of the problem with your image is that it has some area with overbright colors and this is an additional work for the image sampler that waste time trying to antialiasing; you can try unchecking them to verify what has changed; to me not so much. It’s true that the maths behind goes bad.
I think the same, IMHO almost blue is the way to go; it means that image sampler it’s not working so hard. Red means that it’s working hard and needs an higher max value before turning to blue (or raising the clr threshold)
I would like to look at the Morbid findings as well
ok my material subdivs already gone to 512, brute force 64, and I’m STILL getting noise in GI and Reflection elements.
If I switch to light cache for primary and secondary, the GI element is clean. So does that tell me I need to up my BF even more to 128 or even 256??? That sounds excessively high!!??? or is that pretty standard?
I’m really trying to get to grips of using a brute force workflow, so far I’m not getting very far.
