As far as I know, in the compositor, yellow sockets are for images, gray sockets are for values, purple sockets are for vectors. From this, however, I cannot know the ranges of these values. In particular, I am trying to have an image showing the "Vector" pass of the Cycles engine. The "Vector" socket (purple) should be normalized, but in which range? I am trying with different numbers and it seems that it is from -127 to 128, but I am not sure. I am splitting the components, dividing by 128, adding 1 and then multiplying by 0.5 and clamping (clamp means between 0 and 1?).

The first question is: what is the range of the velocity pass? It seems to be the number of delta pixels, so the maximum is the resolution of the image, is this correct?

The second question is: what range the compositor (and the viewer) expects? it seems to me that it expects RGBA values between 0 and 1, and then it multiplies by 255 if the color depth is 8, and by 2^16 if the color depth is 16: is this correct?

  • $\begingroup$ Related to the second question, it's something more complicated, it depends by the color management: blender.stackexchange.com/questions/46825/… $\endgroup$ Jan 16, 2019 at 11:01
  • $\begingroup$ Ok, there is also the color management (that unfortunately cannot be considered in the File Output node). But before the color management, the Composite node expects channels in [0..1] ? What happens with negative values (e.g., from a velocity pass), what happens with higher values, are they all clamped? And what happens if the output is an OpenEXR, that accept floating (also negative?) values? $\endgroup$
    – MadMage
    Jan 17, 2019 at 11:25


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