Confused about Autotile bitmasks

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:bust_in_silhouette: Asked By kojow7

I am having trouble understanding how to apply bitmasks to autotiles. I am currently using the Slates V.2 Updated tileset. However, I am confused as to how to specify ONLY the green grass regions. Here is what I have done:

  1. I have set the step size and subtile size to 32
  2. For my region I have selected everything from 8 blocks across all the way down to the very bottom. This unfortunately selects other areas that I do not need such as (bricks and yellow grass).
  3. I have tried both 2x2 and 3x3 (minimal)
  4. I am confused as to what regions I should be selecting. I have the most success using 3x3 (minimal) and selecting the grassy areas in the first 4 columns of blocks. I select everything in those grassy areas except for the edges. Is this correct?
  5. For the grassy areas in the next four columns I am more confused as the tiles are mostly transparent (black) with only a small bit of grass. What exactly should I be selecting here?

One last issue I am having is that it seems that I get different results depending on what I set as my “Icon”. From my understanding I thought the icon was only supposed to be how the autotile was represented in my list of available tiles. Why is the icon having an effect on how autotiling actually works? Is this a bug?