Been reading about anistropic things and vector flow fields. It was kind of hard at first, but I finally got it. Turns out my problem in understanding was 'complex 1d' instead of 'regular 2d'. Silly me.
It's basically looking at slopes and moving things around based on those slopes.
On the left is expand/contract. Kind of hard to see the arrows, but they are going down the slope. Easy enough to reverse the direction incase you want to go up slope.
Across the bottom are the quick instructions for using Emboss to make this variation. In the R channel, run Emboss with that direction. In the G channel, run Emboss with that direction. The other inputs are largely taste - I've been using 3 and 100%, but feel free to mix it up. B channel is up to you, but ya'll know I prefer 50%.
Save it as a PSD to be used as a D-Map.
I recommend starting with 1% and 1%, then hitting ctrl + f a few times.
With that, the high whites will flow down the slope and into the darker lows.
If you use -1% and -1%, the darks will flow uphill and into the highs.
It's really cool.
On the right is 'stay on the slope' variation. Just gonna call this Slope Var.
Run Emboss in those direction for the R and G channels.
Blah blah blah.
Believe it or not, but there are some uses for this junk.
Take a photo.
Use your favorite edge-detection technique.
Run Emboss for the expand/contract variation.
What you know have is a technique called Displacement Sharpening.
The edges will actually attract surrounding pixels.
Another use is painterly effects.
Once you start getting the hang of Slope Var, you can use a rake-ish brush to direct the flow.
Or direct the flow in other ways.
Another use is to fill in gaps, or inpainting.
For example, erasing the bad stray hairs then filling in the gap using the flow of the good hairs.
If you happen to have Adaptive Equalization, try running it before Embossing.
Really cool stuff.
Now get to fiddling.