V-Ray Learning Adventures: Part 5

Dec 23, 2020 at 09:00 am by nemirc

I am pausing the work on my scene to explore two more features in V-Ray, V-Ray Sun and V-Ray Sky. V-Ray Sun is a very nice light you can use to render exteriors, and you can combine it with V-Ray Sky to add atmosphere to your renders. 

Using V-Ray Sun is tricky. If you perform a test render as soon as you create and position your sun (without adjusting other parameters) you notice the render is extremely bright, sometimes to the point where you don’t see anything except a white image. That’s because V-Ray Sun doesn’t quite work well with Maya’s regular camera, and you have to turn it into a V-Ray Physical camera for it to display correct renders (to do this, select the camera and, in the Attribute Editor, select Attributes\V-Ray\Physical camera). 

After you do that, your image looks closer to what you expect. 

Another thing to notice is that, after you setup your light, if you rotate the light to simulate the sun position, the light’s tint will change to reflect the sun position. This is a very nice touch and it saves you some time, as you don’t need to tweak the light at different positions to get the correct light. When configuring the V-Ray Sun, I found a good workflow was to position the light as if it was noon (the highest point, pointing right downwards) and configure the intensity and color there, and then move it to the position you want so you get the correct morning/noon look. 

As I said before, you can combine V-Ray Sun and V-Ray Sky to add atmosphere to your renders, and there are different things you can do. For example, V-Ray Sun has a parameter that controls how much “pollution” or “air dust” you can see in your render: Turbidity. This parameter can add an interesting look to your render if it needs to have some sense of “pollution” because it adds some exponential fog and also changes the sun tint a little bit, and you can use it in different cases, from a realistic render of a densely populated (and polluted) city, to a render of a fantasy or futuristic environment that needs that look for whatever reason (like a Blade Runner-inspired render). Likewise, another parameter called Ozone lets you control the tint of your light. These parameters sound similar, but the difference is that Ozone only changes the tint, while Turbidity adds the pollution to the scene. 

Another thing you can do for your image’s atmosphere is changing the ground color using the Ground Albedo parameter found in V-Ray Sky (actually, pretty much all parameters of V-Ray Sky are controlled from the V-Ray Sun, and the Sky node offers override parameters in case you want to change them from there). Blend Angle and Horizon Offset can be used to control the horizon line in your sky. 

V-Ray Sun is very helpful when creating exterior renders. I will return to it as I continue working on more scene examples. 

Sections: Tips + Tutorials

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