This page gives details on how the V-Ray Procedural Clouds work in Houdini.
Overview
Craft just the right cloudy sky for your environment in just a few clicks with V-Ray Sun and Sky’s new procedural clouds system. Easily simulate a variety of cloud types and weather conditions, from partly cloudy to overcast. Render realistic stills, or dynamic timelapses.
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Workflow
Environment Sky
The one way to set up Procedural Clouds is through the V-Ray Environment node: ||out Network|| > V-Ray > V-Ray Environment
Inside, create a V-Ray TexSky node and connect it to Background, GI, Reflection and Refraction ports of the Environment Settings.
Go to V-Ray Render Settings > Environment and connect the newly created V-Ray Environment to it.
Note that you would need to have a V-Ray SunLight with the Clouds feature Enabled. If the Sun’s position changes, that reflects on the Procedural Clouds.
Sky Texture
Procedural Clouds can be created using a V-Ray TexSky: ||mat Network|| > V-Ray > Texture: Procedural > V-Ray Sky
Attach the V-Ray TexSky to a V-Ray Dome Light.
Note that you would need to have a V-Ray SunLight with the Clouds feature Enabled. If the Sun’s position changes, that reflects on the Procedural Clouds.
Notes
- By default, the VRaySun and VRaySky are very bright. In the real world, the average solar irradiance is about 1000 W/m^2. Since the image output in V-Ray is in W/m^2/sr, the average RGB values produced by the sun and the sky are about 200.0-300.0 units. This is quite correct from a physical point of view, but is not enough for a nice image. You can either use Color Mapping to bring these values to a smaller range (which is the preferred way), or you can use the Sun's Intensity multiplier to make the sun and sky less bright. Using the V-Ray Physical Camera with suitable values also produces a correct result, without changing the sun and sky parameters.