Cleanup noise in Elements: Reflection and Shadow - Also LOOONG render times

[Dariusz Makowski (Dadal)]

Just a side note - its better to use BB distributed tile rendering than Distributed bucked rendering if u want fastest possibe render speeds per frame...

[zeronove]

Hi Svetlozar,

thanks a lot for your detailed answer, almost everything seems to be clear ...well, for now

Actually, for me, only 3 points are requiring a further clarification:

1. it's lost from my previous post, maybe I was confused about it, sorry; I was asking you informations about min samples (32) inside the DMC rollout, the one just above the global subdivisions multiplier (not the one inside the image sampler); so what's the purpose of this increased value?

2. it's about your suggested LWF (I'm sorry but LWF thing is back!!!); let me summarize just to double check if my understanding is correct:

enable gamma correction in max preferences__________________unchecked
(bitmap files option are now greyed out because of the above)
affect color selectors and affect material editor_________________unchecked
vray gamma by typing 2,2 in color mapping rollout______________enabled
don't affect color_________________________________________chec ked
linear workflow__________________________________________ checked
vray framebuffer sRGB button_______________________________unpressed

3. it's about ambient light: if the target was "to add minimum lighting", could it be a viable alternative just to raise the primary and/or the secondary bounce multiplier?

About my previous attached images, they were rendered just to test your settings (straight out of the box) and to look at the samplerate element, so the interpolation is off (consider they were sended to 3 pc with DR).

The new attachment it's the same as previous (IM/LC no interpolation) with only gamma changed as above described and with subpixel unchecked and LC store direct checked; the the gear is the same, look at the drop in rendertimes; nice discover but I've no idea about the reason, maybe could be the direct light stored in LC? ...it seems too much

Just for the record (or for dev team), IMHO the main issue with reflection interpolation happens when you are often switching from draft to production settings; if you have a lot of materials you always have to remember yourself to rearrange interpolation settings in order to follow IM; maybe a "lock to IM" option could be useful.

[super gnu]

vray automator lets you globally change interpolation settings for all materials. my main issue with interpolation is that i do animation. not so useful in this case.

[Morne]

vray automator lets you globally change interpolation settings for all materials. my main issue with interpolation is that i do animation. not so useful in this case.

for animation, would you recommend to stay away from interpolation?

[super gnu]

yes! it looks rather like perframe irradiance map with too-low settings when you animate. wobbly and blotchy. i guess you could set the min and max to 1 pixel or less, but then that kills any speed advantage.

id love someone to correct me and suggest a way you can use it, as it is a big timesaver, but afaik you just dont use it.

[cecofuli]

VRay Automator, if I remember correctly, not work with nasted sub-material (VRayBlend, Multi-sub-object, VRay2Side etc...)

[zeronove]

vray automator lets you globally change interpolation settings for all materials. my main issue with interpolation is that i do animation. not so useful in this case.

Does this VRay Automator (or similar mass editing scripts) really "automate" the process or you have to remember to run the script every time you switch from draft to production and backward?

[super gnu]

nope im afraid the automator isnt errr. automatic. you would have to type in the settings once each time.

buut, to be honest im not sure how necessary it really is to constantly change the interp. settings. probably its a touch more efficient to stay within the imap ranges, but i cant actually see the major harm in having a few more or less prepasses, since they are generally quite fast, and i dont see that it is doing many more-or less calculations either way..

perhaps if youre trying to get every last percent of speed out...?

[Pixelcon]

Im surprised there isnt a global switch or per-material switch to make vray automatically follow your IR map's settings...

[zeronove]

buut, to be honest im not sure how necessary it really is to constantly change the interp. settings. probably its a touch more efficient to stay within the imap ranges, but i cant actually see the major harm in having a few more or less prepasses, since they are generally quite fast, and i dont see that it is doing many more-or less calculations either way..

I see, maybe you are right but I could say why not? ...if it reveals to be an easy addition

consider that it's not the final render time that matters but all the test render we usually do that waste time (quite fast x 100 means a lot of time and slow feedback)

[super gnu]

very true.. why not indeed.. although burning in my mind now is a list of things about 3 pages long that id like them to do in vray -before adding this feature ;P

[zeronove]

very true.. why not indeed.. although burning in my mind now is a list of things about 3 pages long that id like them to do in vray -before adding this feature ;P

please list' em all

[super gnu]

ahh haha, im sure they have all been listed in other threads, and i suspect it might be classed as a thread hijack if i listed all the things i want vray to do in this thread

[svetlozar.draganov]

1. I was asking you informations about min samples (32) inside the DMC rollout, so what's the purpose of this increased value?

2. it's about your suggested LWF (I'm sorry but LWF thing is back!!!); let me summarize just to double check if my understanding is correct:

enable gamma correction in max preferences__________________unchecked
(bitmap files option are now greyed out because of the above)
affect color selectors and affect material editor_________________unchecked
vray gamma by typing 2,2 in color mapping rollout______________enabled
don't affect color_________________________________________chec ked
linear workflow__________________________________________ checked
vray framebuffer sRGB button_______________________________unpressed

3. it's about ambient light: if the target was "to add minimum lighting", could it be a viable alternative just to raise the primary and/or the secondary bounce multiplier?

The new attachment it's the same as previous (IM/LC no interpolation) with only gamma changed as above described and with subpixel unchecked and LC store direct checked; the the gear is the same, look at the drop in rendertimes; nice discover but I've no idea about the reason, maybe could be the direct light stored in LC? ...it seems too much

1. The purpose of this value is to force Vray to use this value as a Minimum Samples for everything.
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Example :

You have Glossy Reflective Material with 8 subdivisions (This value is the maximum value which Vray will calculate)
In DMC Sampler you have Min Samples = 8

Please pay attention that in Reflective Properties the value is in "Subdivision" but in the DMC Sampler the value is in "Samples"
Sample = Subdivision * Subdivision

Which in this case means - 8 Subdivision = 8*8 = 64 Samples are the maximum samples which Vray will use for this material - but depending on Adaptive Amount - Vray will decide how much of this samples will use for particular calculation.

Let's play 3 scenarios here - Adaptive Amount 0 / 0.5 / 1

a) If Adaptive Amount is 1 - this means that Vray will be fully adaptive which mean that Vray will try to use as less samples as possible - and sometimes vray can decide that 1 sample is enough never mind that you've set 64 Samples in Material Reflection Properties - Remember in every subdivision you set in Vray is the MAXIMUM subdivision - it is not actual Subdivision!!!

b) If Adaptive Amount is 0.5 - this means that Vray will be half adaptive - i.e Vray will use 64/2 = 32 Samples for the Material Reflection Property.

c) And Adaptive Amount 0 - this means that Vray won't be adaptive at all - and it will use the Maximum Samples for the Reflection Property - 64 Samples.

With The Minimum Samples Value you can specify that Vray will always use at least the amount of samples you've set.
If you use the above three examples and add the Minimum Samples = 48 for example:

a) Adaptive Amount = 1 ; Min Samples = 48 - Vray will try to use 1 Sample but with the Min.Samples you force it to use 48
b) Adaptive Amount = 0.5 ; Min Samples = 48 - Vray will try to use 64/2 = 32 Samples but with the Min.Samples you force it to use 48
c) Adaptive Amount = 0 ; Min Samples = 48 - Vray will try to use 64 - and they are already more from Min Samples we specified.

In other words - if you want to always use at least any number of samples for you scene - you can set this value in Min Samples, and don't forget that this parameter is GENERAL - it will use this value for - Material , Lights , etc.

2. LWF
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Two Scenarios Here - a) Final Render (no compositing) - b) Export to Compositing Software

a) If you are not using compositing in your workflow the setup for LWF with Vray will be :
- Max Gamma - OFF
- Linear Multiply
- Dark/Bright Multiplier = 1
- Vray Gamma - 2.2
- Don't Affect Colors - OFF
-Linear Worflow - ON
- sRGB Button - OFF
- NOTE - every 16/32 bit image won't be gamma corrected.

In general - this workflow will convert all 8bit images to be Linear applying "inverse gamma 0.454" - all swatches color will be converted to linear - and at the end Vray will apply back the gamma curve to your final image !

B) Compositing Workflow
- Max Gamma - OFF
- Linear Multiply
- Dark/Bright Multiplier = 1
- Vray Gamma - 2.2
- Don't Affect Colors - ON
-Linear Worflow - ON
- sRGB Button - ON
- NOTE - every 16/32 bit image won't be gamma corrected.

The difference here is that Vray won't apply gamma curve back to your final image - because you will need to continue to work with Linear Data in your compositing software !!!

3. Raise the primary and/or the secondary bounce multiplier?
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Yes you can use this workflow too to increase the light in the hole - I just picked the ambient light - but this will works too

I'll try to render the scene with your settings and to see what's going on !

[svetlozar.draganov]

(*) I simplified the two big bottle (red and blue) shaders (Glass and the bung). But the buckets stay a lot of time on the left glasses. Now the render time 20-25 minutes.
(*) I remove the "Reflect on back side" for the glasses shader. Now the rendering time is 14-17 minutes. Here the new file.
(*) As we know, If I enable Sub-Pixel mapping, the rendering time is 1 minute. Yes, ONE minute. But, obviously, I want it OFF. In this scene we have x15 times. Mmm... Too much difference in rendering time/result.

Hello cecofuli !

We have tested the scene you sent us and here is what we have found.

First I would like to point out that in the attached image has wrong text on it - When Sub-Pixel is ON render time is 1min and when is OFF it is 15minutes.

The question is why this is happening ?
And the answer is - because of Universal Vray Settings.

In your scene you have entered Adaptive DMC Sampler - Min = 1 Max = 100 , as you know this settings produce acceptable results but the time for this render is not optimized at all. What is happening in your scene is that for some pixels (mainly reflective/refractive) Vray use 100 subdivision when Sub-Pixel is OFF - and this is the reason for this excessive rendering times ! When Sub-Pixel is ON Vray use much less samples for this areas - about 6 / 7 subdivisions - and that's why the render is much faster.

The practical difference between Sub-Pixel ON and OFF - is that vray use more samples when Sub-Pixel is OFF - this create better quality but the render time increase - and in some situation this time difference is really huge !

You can fix this by lower Max Value in DMC Sampler like 10/15/20 - but this will also lower the quality of the final render.
And this IES Lights - do they need such higher subdivision = 256 - I've change them to 16 and I can't find any difference in the quality and the rendering time is reduces a lot.

Ok Here are four test renders -

All settings in the scene are the original ones except :
DMC Image Sampler - Max = 25
IES Lights Subdivision = 16

Original Scene Render time : Sup-Pixel OFF - 54min
Sup-Pixel ON - 3min
Modified Scene Render Time : Sup-Pixel OFF - 12min
Sup-Pixel ON - 3min

Unfortunately we couldn't render the whole image but in this small previews we don't think the quality is changed much when Image Sampler Max value and IES Light subdivisions are dropped down, and Yes Sub-Pixel ON produce better rendering times but Sub-Pixel OFF produce better results.