Clouds, Horizons and VRay's Physical Tools

V-Ray V-Ray Common Tutorials, Tips & Tricks
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I have always been a fan of getting as much out of my raw renders as possible without editing in photoshop…using the VRay Sun, Sky and PhysCam system has made it difficult to show clouds and horizon backgrounds without quite a bit of post-comp work.

I used sky domes mapped with a sky and cylinders mapped with a treeline…the geomerty when viewed from inside looks something like this:

Well, I have found a way to use this old method with a new twist, which inherits the physical light properties of the scene. Here is my trial of this method:

7:00 am -

11:00 am -

3:00 pm -

7:00 pm -

And just for kicks,
11:00 pm -

How can you achieve this?

It is actually not very difficult at all! In fact, due to my poor abilities in explaining this, it will probably end up seeming way more difficult than it actually is :sweat_smile: This is the nav view for the clouds material, it probably is the simplest way to explain how this effect is achieved:

The “SkyDayCloudy(L)” map shown in that mat nav is the biggest part of the trick. It basically works as a mask, but with a greater shift towards black, or transparency, which allows the sky color to show through the clouds moreso. I created it in photoshop by selecting a blue color range in the corresponding diffuse image and playing with the fuzziness until I got a pretty good gradient using a grayscale selection preview. I inverted the selection this gave me, filled with white, then made a new layer behind that was black. I then did a gausian blur and a little blending with a few strokes of a low opacity paintbrush to remove any obvious artifacts. I then adjusted brightness and contrast to bias the image more towards dark, or transparent. I removed a few more artifacts that came up due to the adjustment, and that is that.

The next trick, which cannot be seen in the nav view, is that the Output Amount of the Back Material’s diffuse map is boosted to 2.0. This allows the backlighting on the 2-Sided Material to boost the effect of the light hitting it from behind, giving it a natural glow effect.

I faded the diffuse colors for the treeline horizon manually based on distance…amazingly, Vray did the rest when I used the same material setup that was used for the clouds, but with a solid mask/alpha map!

I am sorry if this is too difficult to use from what I have said, but I will be happy to answer questions and pass on the torch if someone is brave enough to make a full-fleged tutorial out of this :smile:

I am sure that with some tinkering and playing with this method it could be refined much more…I cannot wait to see what you guys can do with this :slight_smile:

Later,

Ben

EDIT: I forgot to mention that I disabled cast and recieve shadows on both the sky and treeline objects in their properties.

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10x - but if you post file … :sweat_smile: :lol:

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I will work on that! :smile:

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Here is a file with the necessary resources to play around with. I use gamma correction on my solid colors but not my bitmaps. This file was made in VIZ 2008. Have fun :smile:

P.S. I included a shiny, high-poly geosphere for free, as well as a simple cylindrical column! Get’em while they last :lol:

http://rapidshare.com/files/51072965/Clouds.rar.html

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Thanks for this!

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No problem, glad I can finally give something back to the community :slight_smile:

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You can also use the vraycomp tex to do something very similar, and then you can leave the sky as an enviroment background and skimp on the geometry.

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big 10x

:wink: :!:

:frowning: i can’t open file (3dsmax9 32bit) :frowning:

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Will it merge?

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You can also use a bump map to give more shape to the clouds.

Best regards,
Vlado

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:o

Yes, of course! Thank you vlado! Will test when I have an opportunity :slight_smile:

12

man, this is awesome. I’ll try it with me next scene!

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Here is my attempt with this:











Here is also the .max file:

I used VRaySphere objects for the earth and the clouds, but one can also use VRayPlane objects. The clouds map is also not the best possible…

Best regards,
Vlado

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could you convert the file into max8?

thx

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Turning this into a general ‘sun & sky with clouds’ thread, here’s what you get with the comptex method. Although its pretty basic, I just threw this together and moved the sun around a little:

Theres no geometry in the scene, just the sun.

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That is v cool, I want one!

It it using a image for clouds or procedural?

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Wow, those are some really nice results! Looks like I have quite a bit of messing around to do when I get a little time.

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Thanx beestee, it looks great.

But trying to recreate I am not successfull. My light is not shining through the geosphere. I am using your maps, but what else to I need to set to make the geosphere “transparent” to the sunlight?

cubiclegangster can you explain in more detail what is ment by “comptex method”

vlado, using a daylight assembly and then switching it to a vray light, the photon emitting radius is not shown, is this suppose to be like it?

Thanks to all.

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It is only shown when the VRaySun is selected; I suppose that when it is inside a Daylight, the sun does not actually get selected itself… Some indication may be the bounding box indicators for the sun, which do get updated according to the radius.

Best regards,
Vlado

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cubiclegnaster- how have you done this with no geometry?