Vray dome light resolution vray 3.3

[p0las]

Hi,
I noticed that vray always ignore my HDRI texture resolution and uprezes it to 2k. Why is that? I want it small and blurry (to have faster renders).

Dome light resolution increased from 256 to 2048 for light "VRayLightDomeShape1"

can someone explain why this is done and how is it supposed to help the render?

also I noticed that in vray 3.3 the subdivisions of dome light are locked to 8 and we cannot change them any more (in the attribute editor at least). My optimised scene (one dome light, most of the rays limited to 1, including GI) results with way too many shadow rays:

[2016/Mar/7|19:54:37] V-Ray: Number of raycasts: 2022927310 (3429.71 per pixel)
[2016/Mar/7|19:54:37] V-Ray: Camera rays: 242339439 (410.87 per pixel)
[2016/Mar/7|19:54:37] V-Ray: Shadow rays: 511138904 (866.60 per pixel)
[2016/Mar/7|19:54:37] V-Ray: GI rays: 484652047 (821.69 per pixel)
[2016/Mar/7|19:54:37] V-Ray: Reflection rays: 7328225 (12.42 per pixel)
[2016/Mar/7|19:54:37] V-Ray: Refraction rays: 0 (0.00 per pixel)
[2016/Mar/7|19:54:37] V-Ray: Unshaded rays: 883789424 (1498.40 per pixel)
[2016/Mar/7|19:54:37] V-Ray: Number of light evaluations: 1056691952 (1791.54 per pixel)
[2016/Mar/7|19:54:41] V-Ray: Number of intersectable primitives: 274895

(this is a render of 15 million flowers so 400 camera rays is ok, actually is not high enough as the render still buzzes at the distance).

what are "unshaded rays" btw?

any suggestions welcome

[ivaylo.ivanov]

AFAIK, the minimum size now is 2048 (I guess because a lot of people complained about issues caused by low resolution).

[t.petrov]

also I noticed that in vray 3.30 the subdivisions of dome light are locked to 8 and we cannot change them any more (in the attribute editor at least).

Check this page: http://docs.chaosgroup.com/display/V...plerParameters
And more specifically the "Use local subdivs" parameter.
In 3.3 the default has been changed to make scene setup simpler.
Is this an old scene (made with 3.10) you're editing?

[beenyweenies]

Hi,
I noticed that vray always ignore my HDRI texture resolution and uprezes it to 2k. Why is that? I want it small and blurry (to have faster renders).

I don't think Vray works that way any more. If I remember correctly, Vlado has said that Vray now works the same with regular, full detail HDRs compared to small blurry ones.

[vlado]

This resolution is for an internal structure that V-Ray keeps for sampling the dome light texture and controls the sampling precision. You can still keep you HDR texture small and blurry - it will render fine.

Best regards,
Vlado

[p0las]

Check this page: http://docs.chaosgroup.com/display/V...plerParameters
And more specifically the "Use local subdivs" parameter.
In 3.3 the default has been changed to make scene setup simpler.
Is this an old scene (made with 3.10) you're editing?

it is most likely a scene from 3.1 but I also tried a few scenes created in 3.3. "Subdivs mult" indeed unlocks the settings on the nodes. Thank you for pointing it out!

in my current test case I have a patch of flowers like this:


The final renders will have thousands times more flowers than that. What I want is to most of the samples to go to AA. The shadows gi etc will get resolved by multitude of AA (camera rays) anyway. However my render stats of this render are like this:

Number of raycasts: 125373652 (967.39 per pixel)
Camera rays: 19047258 (146.97 per pixel)
Shadow rays: 36881899 (284.58 per pixel)
GI rays: 42241962 (325.94 per pixel)
Reflection rays: 470492 (3.63 per pixel)
Refraction rays: 0 (0.00 per pixel)
Unshaded rays: 37486243 (289.25 per pixel)
Number of light evaluations: 72840038 (562.04 per pixel)

reflection rays are where I want them (well I wouldn't mind them to be eve lower but this is ok as is) however all the other types of rays are way too high and my camera rays are too low. I tried 'subdivs mult' ON/OFF and this had no effect (I guess with 'divide shading subdivs' turned ON everything is too low to make any difference). I tried to set 'subvivs mult' to 0.1 and again no effect on the stats at all. Setting it to 10 allowed me to increase GI and shadow samples but this is the opposite to what I'm after.

I have all the possible subdivs (shaders, gi, dome light) set to 1.

so my question is: how to lower GI and shadows samples further from that?
and what are 'unshaded rays'?

my render globals:
adaptive,
min 1
max 16
threshold 0.025
use local subdivs ON
dmc adaptive 0.9
dmc threshold 0.015
dmc min samples 16
GI brute force
GI subdivs 1
GI depth 1
dome light as the sole source of light

[Svetlozar Draganov]

Subdivs Multiplier doesn't influence the amount of GI rays when using values bellow 1.0 since V-Ray already use the smallest possible value.
The amount of GI(and other rays) depends also from the Image Sampler settings, so the only option to decrease those rays even more is to decrease the Image Sampler Subdivs value or increase IS Color Threshold.

I am not sure about the Unshaded Rays but according to my test they are related to Light Cache and more specifically to Retrace option.
If you disable Light Cache or Retrace Option those rays should be 0, you can control them by changing LC subdivisions.

[vladimir.nedev]

how to lower GI and shadows samples further from that?

You need to lower the Min Shading Rate in the Image Sampler options.

unshaded rays

The rays that V-Ray Dirt fires are also considered "unshaded" since they only determine occlusion.

Greetings,
Vladimir Nedev

[p0las]

You need to lower the Min Shading Rate in the Image Sampler options.



The rays that V-Ray Dirt fires are also considered "unshaded" since they only determine occlusion.

Greetings,
Vladimir Nedev

thanks. I don't use vray dirt. nor light cache. still I get plenty of them.

fastSSS maybe?

[Svetlozar Draganov]

We could get a better suggestion if you could us the scene for investigation.

[vladimir.nedev]

thanks. I don't use vray dirt. nor light cache. still I get plenty of them.

fastSSS maybe?

Yes, when Multiple Scattering is set to Raytraced.
Also, the new raytraced rounded corners will fire unshaded rays.

Greetings,
Vladimir Nedev