wierd interpretations of screens and louvers

[Chris_T]

I've done some tests with MR sampling settings before.

 

I found that these settings (in the Renderer tab of the Render Scene dialog when MR is the active renderer):

Samples per Pixel: Min=1 Max=16

Contrast: Spatial: RGBA all = 0.1

 

gave results indistinguishable from the same scene rendered with these settings:

Samples per Pixel: Min=1 Max=16

Contrast: Spatial: RGBA all = 0.051 (the default)

 

The rendering times for each setting with the test scene were 51 and 67 seconds respectively.

 

I tried these settings too:

Samples per Pixel: Min=1/4 Max=16

Contrast: Spatial: RGBA all = 0.1

 

...and got a rendering time of 33 seconds. However, there was some aliasing across edges of lowish contrast, but I had to scrutinise the image a bit to find it. I gather what the contrast setting does is set a contrast threshold for AA: adjacent edges that fall within this contrast tolerance (ie: are not significantly lighter or darker than one another) are sampled to a lesser extent, saving rendering time.