God rays, or, more scientifically, volumetric lighting occurs when lights hit airborne particles in the air and create beams of light. They can help to add depth and realism to your visuals. But how do we create them and visualise? Prior to 2024, it was easier to use Nvidia MDL materials to accomplish the god rays. However, since DSPBR’s were released in 2024, the process has become far easier. First, you need a light source. This is best if the light has direction to achieve more light beams rather than just solid fog. Spotlights or IES profiles work well as well as directional lights, especially if there's some geometry to break up The light beams like these blinds. You may also need to turn your scene brightness down so the photometric light has more impact. Next thing to do is add a volume that covers the entire area where you want the atmosphere or fog to be. Primitive shapes from the model tab can be used for these translate scale and rotate as needed. One thing to note is your camera must be outside of this cube for the fog to work. Time to turn the block into fog. We can add a new material by right clicking and select Edit Assign New appearance. If you're in the model selection mode. We need to view all the settings, so change the new appearance type to the enterprise PBR shading model. We want to ensure the outside of the box is not visible or reflective, and the inside has volume. To do this, we set the translucency to one, the transparency to one, and the specular to zero under volume. Untick thin walls and change the index of refraction to one. Our cube will now be invisible. Then comes the three options that will actually create the atmospheric effect. These will be edited in a trial and error basis, as the values will change depending on the size of the model and the light used. The first thing to change is the subsurface colour. This determines the overall colour of the object. After multiple scattering events, essentially, if you are mimicking fog, then you want this to be white or slightly gray. If you are mimicking water, you may want it to be light blue. Almost black can be used if you are trying to fade the background out to black. Great for a dramatic shots. We will make it white and if needed edit it later. Actuation colour is the colour of light inside the volume of the object. Set this to medium grey to start off. This colour value will be manipulated later along with attenuation distance, but the closer the colour is to black, the thicker the fog will get. The closer to white, the thinner the fog will get. However, we need to set the attenuation distance to something sensible before really seeing the effect. Attenuation distance describes the density of the volume and impacts the intensity of the attenuation colour. A value of zero makes the surface opaque. This parameter is dependent on the size of the object. You may need to adjust the value accordingly. Start off with something like one and see what it looks like. You may need to increase it as much as 100 or more, or decrease it to 0.01. Once you see the fog, play around with these three values until you are happy. Ensure the noise is on to prevent very pixelated looks while editing. Be aware that you will need a higher pass count and your render will take 20% longer. When using these volumetric appearances. Be sure to check out our visualise standard and professional courses to learn more about appearances as well as many other elements of visualise.