rendering woes......

[giancarlo_007]

morning guys,

i'm currently working on a project that i sent to render using dr spawner on two twin quad processor machines with 8gb ram last night (one running 32 bit and the other 64 bit and definitely plan to render across the network using 64 bit rendering next time)

unfortunately it was only half way through when in got i this morning and wondered if anyone could possibly shed some expert tips on my current rendering settings which i have found to produce good final results in the past but desperately need to cut back render times...... i pre-rendered the irradiance map and light cache before distributing it across the network and that only took an hour or so to complete.

please find attached a cropped version of the image i'm trying to render which has about 56 ies lights and plenty of reflections and the current rendering settings.....

many thanks if anyone can point me in the right direction, otherwise its back to the testing board

[sv]

The adaptive amount - You could change your adaptive amount back to the default .085, or change it to 0.95 to make it quicker.

Also, as you've got a lot of IES lights and minimum samples on 10, those lights will be doing a lot of sampling which will slow it down.... You could bring the minimum samples back down to 8, or make them lower to 5 or something....

[giancarlo_007]

thanks sv for your prompt response, i've gone round the scene and removed any 3d models which arent in shot and taken out lots of ies lights and replaced them with standard vray lights.... initial testing is coming back with low-res test renders at half the time it took previously.....

changing the min samples to 5 instead of 10 also had a minor effect... the biggest time decrease was changing the aa settings under DMC to 0.95 instead of the 0.5 that i previously had. Unfortunately with that comes alot of unwanted noise, is there something else i can modify to help remove the noise without adjusting the aa?

[sv]

Well the DMC and the AA are split, so you have separate controls for them.
A good way to control it is to set adaptive amount to 1.0 and then use the adaptive DMC AA to set a noise level and a maximum about of subdivision to reach it. However, this works best with Brute Force GI, not Irradiance Maps... Apative amount of 1.0 with Irradiance maps i find can lead to problems.

In this case, perhaps try apadtive amount @ default 0.85, noise at 0.002, and maybe put AA samples to min 1 max 8 and see how much noise you get and what the times are like......

[giancarlo_007]

thanks for all your tips sv, i tried brute force for the initial calculation but it came back with alot of noise and took a while to render..... also tried AA samples 1 to 8 max with dmc settings @ 0.85 and 0.002 noise but came back with a very noisy image which was taking ages to render.

would you typically use brute force as your primary engine with 8 subdivisions? and what other settings would you use in conjunction to that method?

thanks for your help... i've always used irr map in the past

[stilgarna]

Apative amount of 1.0 with Irradiance maps i find can lead to problems.

In this case, perhaps try apadtive amount @ default 0.85, noise at 0.002, and maybe put AA samples to min 1 max 8 and see how much noise you get and what the times are like......

Very interesting... Can you post some image sample ?

Best regards

[sv]

how do you mean?
An example of a poor quality image with Irradiance maps, with adaptive amount 1.0 + with 0.85?

[stilgarna]

how do you mean?
An example of a poor quality image with Irradiance maps, with adaptive amount 1.0 + with 0.85?

Yes, to see the difference and to see if it's really different...

I haven't the time now to test it myself

Best regards...

[sv]

I haven't the time now to test it myself

I haven't!
But i'll try and dig something up when i get a chance - unfortunately i'm away for a few days so it might be after the weekend.

Of course you can get totally decent renders when using adaptive amount 1.0 and irradiance maps, but off the top of my head, i've found that you would have to up the quality a bit for the Ir map (say raise hemi's for example) when at .85 the default medium IR settings were fine...

[giancarlo_007]

morning guys,

sent the same renders last night and out of four sent,two of them rendered successfully and they took 8 hours each, final output rendering size was 2480x1753 and used 8 computers.

done lots of tests yesterday but found the fastest and best quality mid-res render was using Adaptive DMC Sampler Min 1 Max 4 and using dmc sampler thresh. Adap amt. 0.75, Noise Thresh .01, Min samples 5. Indirect illumination was irradiance map and light cache respectively.

SV, what settings are you suggesting? im a little confused by the adap amount being 1.0 and 0.85???

thanks for all your help

[sv]

well of course i'm suggesting going with whatever works!, but if you needed quicker rendering times, increasing the adaptive amount from your original 0.5 can certainly help with this. However, i'm just adding that in my experience, when i've set the adaptive amount to be 1.0 and i've used Irradiance maps, I have noticed i need to increase the quality of the IR map a little to get a clean result - dropping the adaptive amount to the default 0.85 seems to work better with IR maps in my experience. With Brute Force GI setting the adaptive amount to 1.0 and then using the DMC AA settings to control the quality is a REALLY SIMPLE AND POWERFUL way to control the image quality, and you get flawless images & animations - but at a cost of rendering time!