KERNELS: PATH TRACING
Now be ready to hunt for photons in the endless sea of Pathracing. Pathtracing is an advanced "unbiased" render method written for this purpose. With this method, you can obtain photorealistic images with physical certainty. Pathtracing may cause problems in some small light sources or you may not get full efficiency in the case of caustic reflections. In such cases you can use PMC Kernel (see PMC section).
Unfortunately, every good thing has a drawback: this method increases render times. This is the price we will always pay when we try to infiltrate the reality through the computer.
As we have already mentioned, when using the common options of the kernels, there may be only kernel-specific options that you have chosen, or some of the previous ones may not be visible. When you choose Pathtracing, two new features "Caustic blur" and "GI Clamp" are activated. Below we will explain only these options. We have already explained all the other options in this section in Directlighting. You can look at those sections as needed.
This feature is only active in Pathtracing and PMC Kernel. You can set the caustic reflections to look sharp or soft with this option. When you enter a low value, caustics will look sharp, but you can see the bright pixels called "fireflies" depending on the scene setup. When you enter high values, the caustics begin to appear blurry. This is one of the values you will definitely play in scene optimization.
Info: There are a few ways to reduce or eliminate Fireflies. In this Caustic matter, you can lower the GI Clamp value.
It clamps the contribution for each path to the specified value. By reducing the "GI clamp" value, you can reduce the amount of fireflies caused by sparse but very strongly contributing paths, i.e. it reduces noise by removing energy. "Caustic blur", on the other hand, reduces noise by blurring caustics, but conserves energy. Keep this number between 1-3.