Very Looong render times

[gputhige]

Hi

 

we have currently two new systems in our office with the following config:

 

1. I7 Processor

ASUS P7P55D Mobo

ATI Saphire HD 5850 Graphic card

6 GB Ram

 

 

2. I5 Processor

ASUS P7P55D Mobo

Nvidia GTS 250 Graphic card

6 GB Ram

 

We are using 3DS Max 2009 64bit with vray 1.5sp2, Win 7 64bit and working on an interior project. The image is being rendered in 1536 x 1167 resolution with the following vray settings:

 

Primary - Irradiance Map - Medium Preset

Secondary - Light Cache - 1200

Exponential - Dark Mult - 2.0; Bright Multi 1.0;

 

We have used some vray materials like Glass/Wood. There is one sunlight (direct light) with 4 vray lights and a bunch of photometric lights (mostly instances). The render is done in vray Camera.

 

Problem

 

Our current problem is that it takes over 4 - 5 hours to render this single image in vRay.

Question is - is this normal? How can we reduce the render times? These timings are impossible if we were to work on the animation (if the customer desires).

 

Need help desperately on this. We tried almost everything. Updating drivers, bios tried checking on the internet etc.. Cant think of anything else hence this mail.

 

Please suggest. Unfortunately, cannot publish the image as we are bound by the customer contract.

[Arnold Sher]

Hi Giridhar,

 

The never ending quest to drop the time in your renders... I do not see anything particularly wrong with your hardware specs but the usual suspects in time sucking are:

 

1. Materials with too many subdivisions that add nothing to the final render. That usually happens when you download pre-made materials off the web and not exactly sure what it is that you are looking at so than you just change the texture and think what a brilliant 3d artist you.... hahahaha...

 

2. Check your glass for the same thing. Also vray does not particularly like if you look through glass onto another reflective surface.

 

3.Check you vray settings. There is too many variations to go through to see what could be the culprit but if you google something along the line of "best vray settings" something will come up that will be decent enough to start with..

 

Hopefully that helps... good luck...

[Arnold Sher]

one more thing... make sure that your direct like is got vray shadow selected as an option and that your photometric lights select shadow map as an option.. That should speed things up...

[BVI]

 

Our current problem is that it takes over 4 - 5 hours to render this single image in vRay.

 

I suppose that depends how large and detailed the scene is as well as the resolution you are rendering at.

[mahorela]

That's far too long for mine, you could Brute Force most scenes for that.

 

Yeah first place I'd look would be the light subdivs and shadows. I'd also check the AA settings. Adaptive subdivision or DMC settings can easily ramp up render times if your too generous with the settings.

[gputhige]

Hi

 

Arnold: thanks for the response; Yes there are specifically two materials used for Wood and Glass (Frosted) which are vray material downloads and these are taking very long render times. Your suggestion of replacing these are good and will work on the same.

 

Secondly, on the Direct Light - noticed that when I use Direct Light as Sunlight, the shadows are not too good with vray Shadows on. Instead I found that the Shadow map creates better (read sharper) shadows. I have tried switching off the transparent shadows check box in vray, but could not get the right effect with vray shadows.

 

Nicolas: The file size is big (about 74mb) but thats because we have all the rooms in the same file and are rendering one room at a time. The resolution as mentioned is 1536 x 1167; In fact the idea was to move to a higher res as the customer wants it that way. I am afraid, with this setting, the render times may move to over a day??

 

Bob: Thanks. Did move down the AA to Fixed / Area now.

 

Planning to render now. Thanks for all your responses. Was quite worried if the system and/or the os was the culprit esp since we are using 64 bit for the first time.

 

Regards,

GP

[Brian Smith]

you seriously need to do some simple research. the free videos 3DATS has published alone could possibly cut your render times to a fraction of what you are getting now. there are dozens of settings that I suspect are set unnecessarily high, but until you publish a full set of screen shots, know one can know what you're doing right and wrong. One thing you are definitely doing wrong is using the fixed image sampler. Out of curiosity, what is your subdivs value set to for this?

[gputhige]

Hi Brian

 

most of my settings in vray are default and have not been changed. And the ones changed are those which were touched upon in the tutorials (mentioned by you) by 3DATS (currently my Bible for vray Renders). Below are some of the settings with the values (both changed or otherwise).

 

1. AA - Set currently to Fixed - Area - Subdiv - 1 (Earlier - Adaptive Sub

div - Michell-Netravali)

2. GI - Irradiance - Medium - Hsp - 30; Inte - 40;

3. - Light Cache - 1200 ; Sub div - 0.02; Passes 8

4. DMC - Noice Threshold - 0.005;

5. Dynamic Memory - 2000 mb (I have 6gb ram and Max uses only

2 -2.75gb ram for render @ 100% CPU)

6. Colour Map : Exponential; Dark Multi - 2.0; Bright Multi 1.0; Gamma 1.0; Sub-pixel mapping - Yes; Clamp Output - Yes;

 

vray Camera:

f number : 8; Shutter speed 200; Film Speed 700; No other changes

 

3DS Max Gamma/LUT Setting - 2.2; Affec Mat editor -Yes; Bitmap Files - Input 2.2; Output 1.0;

 

All materials (except for vray materials downloaded) are with the default values of subdivisions for all the parameters.

 

Lights - Photometric (IEC) - No shadows; Direct Light - default subdivs; Area Lights with vray Shadows - No Area Shadows

 

No HDRI ;

 

As Arnold pointed out, there are these two vray materials for Glass and Wood which are taking up a lot of render time. We have just rendered another room without these and the render seems to be better - need to load materials for all objects here before jumping to conclusions.

 

However, we notice that 3DS (64 bit) loads much slower now on the new Win 7 64bit at startup. There is a lag in loading up. Wondering if this is any way affecting the render times too? BTW, wouldnt the system use up additional memory available to speed up renders? I mean, we have about 6gb RAM but as mentioned, Max uses only 3gb maximum. Is there a way to get Max to use up the additional RAM?

[mahorela]

What's your dmc sampler global subdiv's multiplier?, The Noise threshold at .005 is strange to me, it's normally set at .01. If I'm getting noise I use the adaptive DMC settings to clear it up. Brian is right, you should not be using a fixed AA method either, most everyone uses adaptive dmc these days although adaptive subdivision can be faster in some circumstances.

Edited April 5, 2010 by mahorela

[gputhige]

Hi Timothy

 

Sorry for the delayed response as we continue our struggle against render times with little LUCK (Probably, what we need right now).

 

The dmc sampler global subdiv's multiplier is set at 1.0 with minimum samples set at 8; Noice threshold has been reduced down to 0.005 to reduce the noice (as recommended in 3DATS tutorials).

 

On a seperate note, we are now facing very strict competition from a team who are using Mental ray and incidentally their output is very good with faster turnaround times. We are finding it tough in the current situation.

 

As said earlier, our 6gb RAM seems to be underutilized and on the flip side, we have long render times.

 

 

Any help would be welcome.

 

Thanks

 

GP

[Brian Smith]

I don't recall mentioning anything like that in any tutorial. If I did, it has likely been taken out of reference. Please elaborate where you got these as they are not correct.

Edited April 6, 2010 by Brian Smith

[mahorela]

Definitely change the noise sampler back to .01, in fact keep all those settings in the dmc sampler rollout standard. Change your image sampler to adaptive dmc, min subdivs at 1 max at 16 (increase if noise prevails), click off the dmc sampler thresh checkbox and set the clr thresh at .005 (reduce if noise prevails). Irradiance map at standard low setting and light cache at 1000. Haven't ever noticed one AA filter being faster than another.

 

Using these settings I render most of my scenes without the need to increase light or material subdivisions.

[gputhige]

Hi Brian

 

most definetely, I must have misunderstood the tutorial somewhere and must have got the noice threshold values wrong. Sorry for that.

 

Tim: thanks for the feedback and will try these settings and trust this should help.

 

Thanks once again to all for the responses. The only other thing bugging me is about the Win 7 64 bit. We continue to have problems with 3DS Max closing out etc which we did not encounter earlier. Is anyone else facing issues with this?

 

Regards,

 

GP

[Djole]

Renderfarm