The Pathtracer node is simply the most accurate and powerful raytracing node.
To understand the Pathtracer node it should be thought of as the following raytracing nodes combined in the one node:
The three main settings in the pathtracer are the Max. Diffuse Depth, Max. Glossy Depth or Max Refraction Depth.
Max. Diffuse Depth #
This will control the number of bounces light will be bounced around the scene, the higher the number of bounces the more the light in the scene will be bounced.
Max. Glossy Depth #
This will control the number of reflection bounces. Set to one and the scene will be reflected once, so reflections won’t show reflections on reflected objects. Set to two and above then reflective surfaces will show up in the reflections of other reflective surfaces.
Max Refraction Depth #
This will set the number of refractions on transparent objects. Set lower and you will only refract through one transparent object, set higher will refract through more transparent objects.
Other notes #
Pathtracer is best used for renders or video if raytracing is needed for a real-time project its best to use RT Glass Refraction and the RT Mirror Reflection. along with lightmap baking your scene.
The pathtracer will still need to be refined or denoised to get the best results.