bagginsbill posted at 7:49PM Wed, 11 December 2019 - #4373043

Suppose you want 150 pixels per inch (you really want 300 PPI for a sharp image but let's go with 150) 24 * 150 is 3600 36 * 150 is 5400 So your image is 3600 by 5400 pixels. A total of 19,440,000 pixels.

Now some images clean up faster than others. A reasonable guess is somewhere between 500 and 5000 samples per pixel.

So you may need 19.44 million * 5000 samples which is 97.2 billion samples.

I don't know what your hardware can do. Suppose it can do 1 million samples per second. That would come out to 27 hours.

My hardware is way slower than that.

it really matters on how the scene is lit, if there is a lot of bounce from the environment, dynamic range of the HDRI if one is used, complexity of the shaders. You can get away with less samples if you use a low res jpg instead of an HDRI for enviro lighting. Small room models (main figure inside a room) will need huge numbers of samples to deal with all the bounce. The shaders can have a huge impact on render speed. I have hair models that HAVE to have the shaders replaced because they slow down the render even on tiles that don't have hair on them.

So the question is what does the scene look like and how is it lit. With this info we could suggest ways of speeding up the render time.

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740