Godrays are most helpful in creating a sense of realism in a render. Hopefully the following will help create a render like the ones below:
We’ll start by creating our atmosphere. Here are the settings I’ve used for the image below.
And Atmosphere settings:
We’re going to create godrays without clouds. Start with the default Vue atmosphere. More of a dusty atmosphere lighting effect one might see in the mountains, forest or desert. Make sure you’re using a Spectral Atmosphere. Set the Light balance (1) almost all the way to the right. You can use Global ambience, Ambient occlusion, Global illumination or Global radiosity for godrays.
Next, in the Sky,Fog and Haze tab, be sure and set the sunlight type to Volumetric sunlight(7) and check the Godrays checkbox (not really necessary as Volumetric sunlight forces Godrays on– but it’s a good habit and won’t confuse you later). Without Volumetric sunlight, you can’t have godrays.
Punch up the Haze ground density so we have more haze to model our godrays with(2). The secret to good godrays is the relationship between Glow intensity(3), Scattering anisotropy, and Aerial perspective(5). Depending on the scene, Aerial perspectives can be anywhere from 5 (at the low end) to 60 (at the ultra high end). You should try starting at 10 and then adjust to suit the apparent scale. In this test render you’ll see the scale is small, so I’ve kept the AP small. Quality boost (6) works well at +1, but for a final render +4 can’t hurt– if you have the time.
You can pull down the Decay amount, which keeps your sky a blueish tint. Use the Decay mean altitude to add a orangish color to scene elements (1).
Here is Vue 7.5 showing the basic components for creating godrays. As you can see, this is a simple geometric construction of cubes. The big cube in the back (1) is a dark area for the godrays to contrast against. If that cube wasn’t there, you wouldn’t see the godrays as the background would be bright. Next, you need something to create a variety of shadows for godrays– in this case I use a series of cubes with gaps between them (2). Next, I positon the sun so as to shine through the slats in the cubes (3) and create the shadows (4). If the settings are correct, the godrays will automatically appear. It may take some trial and error to get it just right, but as you can see, it does help create a very realistic render. I’ll post more renders in future posts.
I’ve been inspired by the great renders of Dax Pandhi at QuadSpinner. There he has some super tutorials. You might want to check out his Capturing the Brillance of Light. I learned plenty by watching it!
