Unable to render Light Rays (Vray Light Volume)

[izumiaiko]

Hi,

 

 

As the picture shown. I am unable to render the light ray of my directional light out although different settings were used throughout the process of trial and error.

 

 

Using Shadow Map with/without global Setting the whole light ray turns into Black/Grey colour upon rendered. While using Vray Shadow Map with/without Global Setting will just remove all light ray after I rendered.

 

 

As attached in this thread is the JPEG of the Black/Grey Light Ray render and the full settings I have for this Light Ray Effect I wanted on my Directional Light.

 

 

Please help.

Thanks

[Corey Beaulieu]

Use Raytraced Shadows. (I think that is how it works.) and override all material to black and hide glass. This should be rendered separately as a pass to ADD over the top of your image.

[RyderSK]

Use Raytraced Shadows.

 

No.

 

 

 

You're using Vray and this approach is obsolete, it doesn't work.

 

The way to obtain "god rays" in Vray is by using "VrayEnvironment" fog, not "VolumeLight". VrayEnvironment fog works with any physical light-source and nothing else needs to be done, but visible rays are obviously prominent with directional light.

 

If you prefer to use "directional light" instead of simpler to use "VraySun", it should by default be set to "VrayShadows".

 

It can be rendered directly in beauty image, or it can indeed be rendered in scene with black override material (ideally VrayLightMaterial set to black to avoid any sampling) but then you need to hide glass in windows.

It also generates separate pass called "Environment pass", which is best added as "Screen" in non-linear mode (gamma 2.2) or "linear(ADD)" linear mode (Gamma 1.0) in Photoshop.

 

There should be some good tutorials in Vray manual, but also on Peter Guthrie's blog, or other places.

[izumiaiko]

No.

 

 

 

You're using Vray and this approach is obsolete, it doesn't work.

 

The way to obtain "god rays" in Vray is by using "VrayEnvironment" fog, not "VolumeLight". VrayEnvironment fog works with any physical light-source and nothing else needs to be done, but visible rays are obviously prominent with directional light.

 

If you prefer to use "directional light" instead of simpler to use "VraySun", it should by default be set to "VrayShadows".

 

It can be rendered directly in beauty image, or it can indeed be rendered in scene with black override material (ideally VrayLightMaterial set to black to avoid any sampling) but then you need to hide glass in windows.

It also generates separate pass called "Environment pass", which is best added as "Screen" in non-linear mode (gamma 2.2) or "linear(ADD)" linear mode (Gamma 1.0) in Photoshop.

 

There should be some good tutorials in Vray manual, but also on Peter Guthrie's blog, or other places.

 

 

hi!

Thanks for the tips! may I know the steps to making the "god rays" if i were to stick with Vraysun? I have tried googling for hours and I cant find a way that works..

[Corey Beaulieu]

No huh? Just no?

 

Haha

 

I think old school works just fine considering "God rays" are a fantasy add.

 

I get it. There is a better way, but God Rays are hardly a realistic factor to an image.

 

I still would not bake them in. Getting that dialed in will be a lot of testing. Just render it as a pass and control it in post.

 

 

Sent from my iPhone using Tapatalk

[izumiaiko]

I tried what u had said and the rays just doesn't show anything at all...

I had tried different tutorials according to youtube and everything just turns out disappointing (Doesn't work at all).

 

 

Settings:

 

 

Result:

[RyderSK]

No huh? Just no?

 

Haha

 

I think old school works just fine considering "God rays" are a fantasy add.

 

I get it. There is a better way, but God Rays are hardly a realistic factor to an image.

 

I still would not bake them in. Getting that dialed in will be a lot of testing. Just render it as a pass and control it in post.

 

 

Sent from my iPhone using Tapatalk

 

What are you talking about here ?

 

No to "Ray-traced shadows". Raytraced shadows are for MentalRay, not Vray.

 

The rest was fine. That's why I quoted only part of that post. Perhaps I could have clearer but I find it pretty obvious from context. I have no idea what you call "Old school" now, what you refer to is normal approach, you just described it wrong technically.

"Obsolete" was the approach Izumi had from I presume old tutorial, which is how it worked in MentalRay.

[RyderSK]

http://www.peterguthrie.net/blog/2009/03/canova-museum-take-3

 

The steps for setting up the environment fog in 3dsmax couldn't be simpler: I just added a VrayEnvironmentFog effect in the environment & atmospherics window (8), set the density to 20,000 (20 metres), enabled scatter GI (100 bounces) and set the fog height to cover the whole building. Plus, from the vray manual: "When using VRayEnvironmentFog, it is recommended to turn on the Optimized atmospherics evaluation option in the System rollout of the V-Ray settings."

 

You can than apply black material override and save only the "Environment pass".

 

[Corey Beaulieu]

I was only laughing at the directness of the your "no". That's all.

 

I probably should not have responded as I am not entirely sure but I know that last time I used volume light it required a specific shadow type. I thought it was ray traced shadows even though they don't otherwise work.

 

I still think that is correct but I still could be off base here.

 

In any case. I don't think that volume lights are all that effective and should be used sparingly. If almost say that if you are looking to use one, you may be best suited to paint it. That low rent but still.

 

 

Sent from my iPhone using Tapatalk

[Mamoon Bestani]

do one thing, use vray sun light , as you did in environment you already add VRayEnvironmentFog, that's

fine. just click in VRayEnvironmentFog Nodes " add " and select vray sunlight

only ,, preferred to used this light with vray physical camera ...

 

 

______________________________

http://www.dubai3dmax.com/

[izumiaiko]

http://www.peterguthrie.net/blog/2009/03/canova-museum-take-3

 

 

 

You can than apply black material override and save only the "Environment pass".

 

 

 

Hi,

 

Thank you so much for everything..

BUT, I am still unable to get the effect like the Museum u had shown...

 

 

 

The following is my setting + Renders (Test):

 

 

 

 

Renders:

 

 

[Corey Beaulieu]

Juraj,

 

Will you PM? I want to talk to you about something and your PM is blocked.

 

Thanks,

 

Corey

[RyderSK]

I was only laughing at the directness of the your "no". That's all.

 

I probably should not have responded as I am not entirely sure but I know that last time I used volume light it required a specific shadow type. I thought it was ray traced shadows even though they don't otherwise work.

 

I still think that is correct but I still could be off base here.

 

In any case. I don't think that volume lights are all that effective and should be used sparingly. If almost say that if you are looking to use one, you may be best suited to paint it. That low rent but still.

 

 

Sent from my iPhone using Tapatalk

 

Ah, lol, well I felt like there is nothing else I should add to it, don't read into it far, that's just how I write :- ).

 

I both agree and disagree with latter sentiment. I feel light rays can be very realistic done right (the fog is after all completely correct medium to do so, this is not fake trick), but it has to be done carefully and with caution.

 

Yeah, in most cases they can be painted. I used it only when the shape was complicated to do correctly (from tree leaves).

 

Juraj,

 

Will you PM? I want to talk to you about something and your PM is blocked.

 

Thanks,

 

Corey

 

Yeah I blocked it because using message system is both sort of archaic and confusing, there are far too many platforms I am part of so.

---) Email ( name.surname @ yahoo [dot] com )

[RyderSK]

 

...

 

 

Check (all) your units.

[Corey Beaulieu]

Ah, lol, well I felt like there is nothing else I should add to it, don't read into it far, that's just how I write :- ).

 

I both agree and disagree with latter sentiment. I feel light rays can be very realistic done right (the fog is after all completely correct medium to do so, this is not fake trick), but it has to be done carefully and with caution.

 

Yeah, in most cases they can be painted. I used it only when the shape was complicated to do correctly (from tree leaves).

 

 

 

Yeah I blocked it because using message system is both sort of archaic and confusing, there are far too many platforms I am part of so.

---) Email ( name.surname @ yahoo [dot] com )

 

Agreed. It can be effective, but the case is rare.

 

I sent you a message. Hopefully it reached you.