In theory you should leave it at “1” since it is supposed to give physically correct results. Other parameters: Multiplier – it makes the caustics brighter if increased, or less bright if a value lower than “1” is assigned to it. Basically by increasing the caustics subdivisions we ended up with more photons acting like “case 2” of the diagram.
You would expect better results, right? WRONG! The result looks exactly like the one with max density set to “1”. In order to realize just how tricky this max density can be, leave it at 0.002 (that works fine at the moment, as seen in the rendering above) and increase the caustics subdivisions of the direct light to 50000 and run another test rendering. If no other photon is found within that radius, the new photon will be stored in the photon map (case 1 of the diagram).Īfter doing some tests, I think that a value of 0.002 works just fine for this scene. If the area is too large the end result will look like there are no caustics in the rendering. If it finds one, it will just add the energy to the one in the map, in order to keep the photon map at a smaller size (case 2 of the diagram). If max density is greater than “0”, when vray needs to store a new photon, it will look if there is another photon within the radius specified by this parameter. Max density is probably the trickiest parameter, and if you don’t understand how it really works, you can end up with unexpected and undesired results.įirst, let’s do a test increase the max density from “0” to “1” and look what happens: The caustics still look a bit noisy, but we will try to adjust this by tweaking the “ max density” parameter. Higher values result in smoother caustic effects, but at the same time the higher the values, the blurrier they get.Īfter several tests, I am happy with a search distance value of 0.09 for this scene. If we change the “ search distance” parameter to 0.02 we will end up with something like following:Īs it can easily be observed, smaller values produce much sharper caustics but a lot more noisy. The caustics are starting to look more real. For this, you need to right click on the direct light, choose vray properties and increase the “caustics subdivisions” from 1500 to 20000 and render it again. The most important parameter that we need to adjust is the “ caustics subdivisions” that are emitted by the light. The caustics effects are already visible but they have a fake look and lack definition. If you render it at this stage you will end up with something like this: reflect 213:213:213 with fresnel reflections checked.įirst, go to the “ Vray: caustics” rollout and activate it by checking the box next to it.
#VRAY TUTURIALS ZIP#
Open the “caustics start” scene that you will find in this zip file.Īs you can see, the glass material is already prepared: In the next tutorial I will try to explain what parameters you need to control in order to obtain realistic caustic effects with 3ds max and vray.
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