quality vs time

[bluediablito]

Hello all.......first thing first;

my spec

cpu -i7 930

ram - 12gb

gpu - ati hd-5870

os - windows 7 64x

 

ok with that said, my question.

when it comes to rendering a still image, is there a way to achieve good quality without the long wait? or waiting is good?

 

my question came to me while i was at school and i was introduce to solidrock. i notice that this plug in is made to simplify everything when it comes to setting up vray,but i grab one of my scene (3d max file) and i set light ch/im and set it to medium and the rendering est. time was 8hr. with my setting i made it render in 2.30hr. is this normal or is the setting of solid work will give me a better quality? more realistic?

 

these are my settings

[Thablanch]

Your settings seems quite correct for a nice quality image..

 

In the Vray system rollout, I would increase the Dynamic memory limit...

to something like 6000... ( half your ram value) This is going to speed up things as you have a really decent system.. You would do the same scene with 4GB of ram, you would use 2048 in the dynamic memory limit and so on....

[ruskie77]

I'd agree.. but there's a couple of other things I do as standard but I couldnt say if they're "right or wrong"

 

the adaptive dmc (0.005) sampler will slow you down a lot, try adaptive subdivision with min0 max4 thresh 0.05

 

 

 

I notice that you're not using a LWF.. as your colour mapping gamma is set to 1... do you find your images a little dark sometimes?

 

also I notice you dont have "clamp output" ticked.. ever get strange coloured splotches/speckles in your extreme highlights or shadows?

 

IRmap settings: with a high(ish) HSph subdivs of 80, try increasing your Interp samples to at least 30 (but no more than 50) to finely hone those GI splotches.

 

your calc pass interpolation samples is too low.. could lead to splotches, at least 15 is in order here. (no more than 20 though)

 

I wouldnt use the light cache for glossy rays (unless you've got a serious amount of blurry reflections) otherwise it kind of "over-smooths" the fade.. especially when you're subdivs are only @ 1000..

 

also, your i7-930 is a quad core so unless you've hyperthreaded to 8 "cores", drop the light cache passes to 4

 

settings rollout;

I always put the DMS Sampler adaptive amount up to 1 or 0.99 this allows the sampler to go fully adaptive, and you'll get some really good speed savings. also, min samples here of 8 "should" usually be enough.

 

Now with a sexy machine of 12GB I've found the biggest saving (for still images) to be in the "default geometry" setting.. 99% of the time (unless I start running out of memory) I have this set to static.. it saves a LOT of disc writes and depending on your scene, it can save a huge amount of time... although watch your ram via the task manager and set back to auto if you start getting close to the limit.

 

 

and finally, I like to tick "low thread priority" that way, if you need to jump onto your machine for any other reason, you can leave the render going, without the machine stuttering and P*** arsing around on you!

 

 

I'd love to hear everyone's feedback.. I'm no expert by any means, and everything I've written could be wrong I'll not take offence if I am!

 

 

any chance you could post your final render so that we can see what the scene consists of?

 

 

also... are you using interpolation in your materials at all??

 

all the best.

 

Russ

[Tommy L]

Render quality/time issues are scene specific. So without seeing the scene its difficult to give accurate advice.

[bluediablito]

thnk you for the reply.

Thablanch ---thank your. yes i did change the memory from 4 to 6000

ruskie77- yes i am doing hyper threaded. also the color map is set to lwf sorry that i post the unchanged settings. and i am currently trying out your settings to see the results. hope they are better than the one i have

 

one thing that i did notice and i am confuse about is.

when rendering in max the images in 3d max frame buffer is lighter than vray fb (meaning the image looks washout in max's fb but in vray fv its darker) and when i do save the image and open it in windows image viewer it looks darker but in photoshop it looks lighter. any suggestions to why this problem? (is it the Gama)

 

this is my raw image. i know i have a long way to go in rendering and making the images look realistic but hey i am trying to find out what works for my and thank your all for helping me and suggesting anything that will help me improve.

 

 

(it looks better in tif had to save it as a jpg to upload )

[bluediablito]

hey ruskie77

i have change to

adaptive sub - max 4 min 0 thr .05

IRmap settings - subdivs 80, Interp samples 35

light cache subdivs - 2000

light cache - passes 8 it sees 8core (hyper) i guess no prob there

 

settings roll-out

 

DMS Sampler adaptive amount - 1

default geometry - static

dy. mem. limit - 6000

render region divi - 32 (i see that it has less sharp edges from 64x64)(also what changes would this do.....would it give me a sharper image with less jagged edge without adding any filter?)

low thread priority - ticked (just curious what does this do?)

 

will post the image to see what major changes .

 

 

don't know what you meant by lwf (linear work flow i guess) but how would i change the gamma like you said? (i guess in color mapp.. change type to linear multiply and change the gamma to 2.2?)

and if i tick clamp output what number should i set it to ?

and does it matter if i change my 3d max gamma to this (http://www.aversis.be/tutorials/vray/popup.htm?images/essential_gamma/big/gamma_12.jpg)

[ruskie77]

Hello again!! I'm loving your render! that's a nice bit of design... how much work have you done in post?

 

I'll answer these bits as best as possible.. but like I say, I'm no expert, and could be very wrong!

 

as far as I'm aware, the reason that the max FB and the Vray FB are different in your case is all down the the output gamma as set in the max preferences. the aversis screen grab of settings is nearly what I use, however, I have the default bitmap input gamma set to 2.2 leaving the output gamma set to 1.0

 

if you dont change the input bitmap gamma to 2.2, all your texture maps will load up with the wrong gamma (unless you change it on each bitmap, when you load it.)

 

I use the rhinard (wrong spelling, I know) colour mapping and set my gamma in there to correct the image..

now, If you set that gamma to 2.2 AND the max preferences gamma to 2.2 you're going to "double gamma correct" and it'll give you a very washed out feel.

 

I would REALLY recommend investing in Vray RT and watching the realtime feedback as you change these settings.

 

Now as an interesting point, I have all my gamma settings set up for 2.2 workflow (except max's output preference) but I have found that if I have my colour correction rollout reading 1.6-1.8 gamma I get really rich moody renders. play with it. easiest way is to render a 32bit hdr or exr image and chuck it into photoshop and apply an "exposure" adjustment layer. It's important to note that all hdr images "should" be gamma 1. (open up any freely available hdr image to see this)

 

If the image is too dark, start by putting a gamma correction (via the exposure layer) to 2.2 and then tweak up and down from there... but if the image is too washed out and bright... set the gamma correction to .4545 (its the inverse/reciprocal of 2.2 ( calculated by dividing 1 by 2.2))

 

play with gamma, you can save a lot of renders in this way. I usually save out as 16bit tif and then work on those.

 

Now the clamp value is a funny setting.. the short answer is... leave it at 1.

the long answer is.... (deep breath) 8 bit colour goes from 0-255... but 32 bit colour (vray's ALWAYS renders to 32 bit) is a true floating point colour and the colours go from 0 to 1 with the billions of decimals in between... (although extremely bright colours go above 1) therefore, clamping at 1 is usually the right way to go. but there are rare exceptions to this.

 

just out of interest, how did you get along with those settings? did you see any improvment?

 

the low thread Priority button wont come into effect until you try to do something else on your machine... windows will just allow your email/browser/whatever to take more system resources. but if you leave your machine alone it'll render at very close to having it unticked. it's a kind of win/win button in my opinion. (although if anyone can shed mpre light on that, I'd love to know more about it myself)

 

I know I'm waffling now! but a few resources I would really recommend are..

http://www.thegnomonworkshop.com/store/products/tutorials/cni03/

http://www.thegnomonworkshop.com/store/product/33/Global-Illumination%3A-Interiors

http://www.thegnomonworkshop.com/store/product/31/Global-Illumination%3A-Exteriors

 

that guy is a Vray Ninja and the vidoes are worth their weight in gold!

 

and if you really want to look under the bonnet/hood of vray have a look at

http://www.francescolegrenzi.com/blog/static.php?page=vray_guide_eng

 

very handy to have on your shelf.

 

I hope this helps in some way, and If anyone knows anything more... lets get the conversation going.

[bluediablito]

hey ruskie77

Thank you again for your quick reply. wow this gamma stuff is complicated. as of now i only have max gamma set to 2.2, affect color selectors / affect material ed tick on with input and out put gamma to 1.0. but i will change the input to 2.2 (but i still don't understand why would you put input to 2.2 but not out put to 2.2)

and you also stated that if i makes the gamma correction in max i shouldn't make any gamma correction in vray. what do you recommend i change the max or the vray?

 

also in photoshop i don't know if i did the correct thing but i change the gamma to match my lcd and the images look the same as the windows viewer.

 

this is my scene render with ruskie77 recommendation. (my raw images)

things that i notice was that it render with less time and the quality is good.

the max gamma when rendering was set to 2.2 and the input and output was 1.0...

color mapping in vray was set to linear multiply with gamma set to 2.2

( i think this is what you mean about color wash by having vray gamma set to 2.2 and max gamma 2.2)