Is there a simple way to do a volume rendering of two variables simultaneously? For example, if I wanted to overplot both density and temperature into a single volume rendering. My naive method would be to define a new variable which is a weighted sum of the two variables, and sculpt the transfer function to have different colors over the range. I'm just asking if there's a better way built into YT.
I've done a lot of searching through the documentation, but I can't find
a clear answer as to whether this is a built-in feature. I've seen
examples from a few years ago where both variables are rendered
separately, and the PNG files are combined. This ends up with both
variables being partially-transparent to the other variable; in my
example, I'd prefer not
to see through a particularly high-temperature region. I've also seen documentation on a "multi-variate transfer function", but that documentation is pretty incomplete.