Nodes - Bug or Misunderstanding


I have been experimenting with nodes in Blender 2.49 and I think I have possibly found a bug/issue with the nodes.

The full explanation is here:

As the pictures here go fuzzy when displayed here so larger version are available on the link above.

If anyone can explain what I am doing wrong or confirm that this is a bug it would help a lot.


Check this out, there is a simpler way.


FloridaJo: Thanks for the reply. I have used the keyer that’s internal to Blender, it’s very good, but the point of using the method I showed above was to try and determine if the node editor has a bug or not. Also using the discrete nodes rather than the internal keyer helps me with getting to grips with the pixel math involved. It’s been fun so far but this issue has been driving me up the wall.

  1. u need to save the png with the RGBA button enabled.
  2. the main issue is that white and tan has green in it, so simply selecting the green channel in the separate node will include all pixels. The chroma nodes (chapter 11 in my book) work on a specific (narrow) range of color, which may be a shade of blue or green. so if you want to devise a mask based on that, use the other math functions, like screen or divide, with that color, feeding something like a minimum, to get a mask.


Papasmurf: Thanks for the info, I will investigate and see if I can fix with the info given. Also your book I have had on preorder for a while! Now amazon just have to feel like shipping it.