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QMC(primary)LC(secondary)---issues


batteryoperatedlettuce
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I'm totally new to V-ray. I read a PDF on some critical settings and rendered accordingly. I threw some stuff into a room and did a test render. Please excuse the table, I copied it from a model I saw in one of the galleries here. (if it's your design I'll happily swap you the piano in return :) )

 

I used QMC for primary and Light Cache for secondary.

 

QMC subdivisions = 22

LC subdivisions = 2000/sample size 0.01 (screen)

 

I have three lights,

sun = vray sphere subdivisions at 25

Two vray lights at window subdivisions at 25

 

I'm not happy with either the output or the rendering time. Can someone suggest a solution to get rid of the noise and speed it up a bit?

 

2f-sch01.jpg

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Have done exactly as you suggested and the result seems to be OK.

 

The render time has been almost halved, which is good and the noise issue has been greatly reduced.

 

In your opinion, what direction should I take if I really wanted to push the rendering quality up another notch, while having the least effect on the render time?

 

Also what do you recon a rendertime for a scene like this should be on a fairly robust dual processor machine?

 

Your help and advice is very much appreciated.

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Right, I've just started to play with vray materials in that render. All the materials are vray in there I think - I've tried to keep it clean. Any advice on materials would be a huge help. I've downloaded some other professionally produced architectural renderings and done a bit of research, but like most things it's hard to trust stuff untill it's been explained by a pro.

 

I'm going to render out some small images now with the suggested values and see what happens.

 

I think the lighting level is generally OK, but I'm just looking for a shaper clearer image with no fuzz. A render time of about 25 seconds would be good too :D

 

edit:- @Christopher Nichols, you'll have to bear with me. When you say "standard values" could you tell me what the standard values are. I've done so much with this file now that I'm a bit lost. Many thanks.

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kev, if thats what u got when ur "totally new to vray" then its scary to think what ull do when u get to know it better..!

im no pro but i think ur image is very high level plus i actually like the noise, it has that "maxwelly" look to it, but thats my taste nothing more.

 

and christopher- "min 1 max 16 in the AA".. isnt that alittle too much?

again im no pro but sounds abit of 'overkill' dont u think? especially if the guy is hung on rendering time.

 

i think checking the 'store with irr map' in the vray lights is supposed to get rid of most of the noise anyway so up to u kev.

 

p.s.- kev did u do any ps work on this image? if not then how did u get that glow in the back of the room? is it just a mis-hap or intended?

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Cheers - I've had a pretty good run with mental ray up to now, but there's just so many people writing about/talking about vray nowadays.

 

The glow is intended. I wanted it a bit bleached out at the back to focus on the foreground content. Not sure how beautiful the intended result is.

 

I saved as 32 bit hdr and tweaked the gamma/exposure + added a very faint photo filter, before converting to 8bit for jpg. nothing more than you'd do for any digital photograph really.

 

I've been playing around with the render settings and running into all kinds of messed up problems. :D I'm in over my head right now...:eek:

 

-edit: I'm totally on top of this problem now. I'm rendering fairly dark and then adjusting to lighten it, which I ought to know is going to cause all kinds of dilema. trouble is if I up the lighting I lose all the depth in my shadows. would turning down the heat on the secondary bounce allow me to blast up the sun and still retain strong shadows ???????

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and christopher- "min 1 max 16 in the AA".. isnt that alittle too much?

again im no pro but sounds abit of 'overkill' dont u think? especially if the guy is hung on rendering time.

 

Actually not at all... If you read Vlado's "Universal Settings" tutorial, he suggests 1 and 100.

 

Vray is highly adaptive, and the QMC can be used to deal with ALL noise. That is why I told him to set the values down to "standard" values in order to let the QMC deal with the noise.

 

Standard values... Take all your shadows and set them back to 8 subivs. Take your QMC GI and set that back to 8 as well. etc...

 

I'm actually working on a tutorial using these techniques... to be expected soon... :)

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A-HA!! i knew i saw some ps in here... :p

of course its totally legit!

as for the burn-out i like it personally, looks more natural to me. but again i can speak only for myself.

 

as for chris- a 100!? wow.. im using 0 to 4 (adaptive) and its taking me sooo long to render. guess thats a job for a monster pc though, im just trying to get along with my dual amd...:(

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A-HA!! i knew i saw some ps in here... :p

of course its totally legit!

as for the burn-out i like it personally, looks more natural to me. but again i can speak only for myself.

 

as for chris- a 100!? wow.. im using 0 to 4 (adaptive) and its taking me sooo long to render. guess thats a job for a monster pc though, im just trying to get along with my dual amd...:(

 

Keep in mind that adaptive at 0 and 4 is equivilent to QMC 1 and 16, since Adaptive is in measured in rates and QMC in Subdivs. Again... read the Universal settings tutorial and you will see what while 100 is the max, it hardly ever need to get that high.... that is simply the max. If you set your scene up right, you can get some pretty good rendertimes using these smart settings... nothing to do with your PC speed.

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a 100!? wow.. guess thats a job for a monster pc though, (

 

 

The results are really good however. You do have to have the time to let it clear its worth looking into using if you have a scene you want to play with and have the time.

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Standard values... Take all your shadows and set them back to 8 subivs. Take your QMC GI and set that back to 8 as well. etc...

 

That's actually quite an unexpected piece of advice. I have to knock out a few renders, and I've managed to get the render speed down to a reasonable level to meet my current deadline (Didn't pick an ideal time to switch render engines).

 

When this is out of the way I'll post the results and I will play around with the values you have suggested.

 

Very much look forward to your tutorial. Let me know when it arrives.

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Anyway - it's a few days later now and I've managed to produce a bunch of renderings for my current project, which is the conversion of an old block into apartments. I had to populate a lot of them with less than perfect models as I really didn't have time to put everything together the way I wanted.

 

I think I've got the irradiance map+LC working the way I want it with all render times under 3 hours on a 2g machine and no noise - woo.

 

Thanks for the advice all round. I didn't pick a good time to start learning a new render engine and I don't think I'd have got much done without the resources at this site. The attached bathroom rendering is my fifth attempt at doing an interior with Vray. Comments welcome.

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Xmas in April?

Did I just read "tutorial" by Christopher Nichols? When....? Where....? I've been anxiously waiting for something new since the last Gnomon DVD!

Actually not at all... If you read Vlado's "Universal Settings" tutorial, he suggests 1 and 100.

 

Vray is highly adaptive, and the QMC can be used to deal with ALL noise. That is why I told him to set the values down to "standard" values in order to let the QMC deal with the noise.

 

Standard values... Take all your shadows and set them back to 8 subivs. Take your QMC GI and set that back to 8 as well. etc...

 

I'm actually working on a tutorial using these techniques... to be expected soon... :)

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