With "Branched Pathtracing", you could set the "Anti-Aliasing" Samples(*) to for example20 (this is the number in the "Render Samples" field and the "Diffuse Sub Samples" to 4 in order to get 80 Samples per pixel for rays hitting a diffuse surface at the first bounce after beeing sent out from the camera. The same number could be achieved with just 1 "Anti-Aliasing" Sample and 80 "Diffuse" Samples. What is faster and/or gives the best render results given a scene with mainly diffuse objects. Of course, for a complex scene with many different surface types, it can be necessary with respect to the rendering time that you need to do the adjustment in the "Sub Samples" section.

(*) that is the number of "Camera Rays" sent out per pixel in order to calculate an average light value which approximates the real world lighting more or less accurate depending on the number of samples choosen)

21.30-22.25, when filling the faces the last one wont fill. It works when i select three of four verts, but not for all four or witht he edges like in the tutorial. The "F2 addon" is enabled and there doesnt seem to be any duplicate geometry. It deosnt amtter which three i select, it fills anyway.

There're three transparent bounces with the "Transparency Bounces" maximum number set to 2: The area of the third bounce (after which some rays hit the light emitting world background) is marked with a red arrow in the image below:

Bounces counting in Cycles starts at zero (please see the "Cycles Encyclopedia" by Frederik Steinmetz and Gottfried Hoffmann)

With glossy bounces set to 1, the mirror in the background mirrors from the mirror in the foreground only that part, where the foreground mirror reflects the light (environment texture) of the world background, since there'e 2 glossy bounces (bounces counting in Cycles starts with 0 !): 

I'm talking about the camera rays hitting the background mirror first (glossy bounce number 0) and then the outer areas of the foreground mirror (glossy bounce number 1) before hitting the world background. The black square in the background mirror is caused by the rays coming from the foreground mirror and hitting the background mirror which would cause a third glossy bounce (number 2) that isn't allowed with the current glossy bounces counter set to the maximum glossy bounce number 1.

So what if I have mesh-based eyelashes that I would like to apply the same blinking shape key to. What would you say is the best/easiest way to do this? Having both eyelid and eyelash in one object, or make both separate objects and apply separate shape keys? I ask because sometimes when I tell blender to mirror the shape key, it doesn't do it to the eyelash, or if it does it isn't deforming right.

Can't believe this is going to be the 8th stream so far. 2020 has turned out to be a gr8t year for the Dog pound.

Can I say that mixing the "Principled BSDF" shader and "Translucent BSDF" shader with a different color for the last one is an artistic decision whereas using the "Transmission" setting and the "Translucent" setting of the "Principled BSDF" node would achieve a physically more accurate result?