I ran into this conundrum while trying to combine two normal maps using  DAZ Studio 4.5's Shader Mixer. For a long time I thought the problem was in my maths, so I decided to start again from scratch, putting the maths in one step at a time. I was really surprised when the very first bit of maths I tried caused the same problem!

The attached image shows a very simple network at the top (works fine), and a similar one at the bottom (doesn't work - object renders completely black).

The only difference is that the top network plugs Z Component directly into Z Value, whereas the bottom plugs a calculated value into Z Value, the calculated value being √(Z Component*Z Component) , which should equal Z Component, same as the first network (or possibly -Z Component, I've already checked and that's not the problem here)

I've asked this question in various forms over on various DAZ forums, but nobody seems to have the answer.

Anybody over here have any ideas?

---

The 3Dcheapskate* occasionally posts sensible stuff. Usually by accident.
And it usually uses Poser 11, with units set to inches. Except when it's using Poser 6 or PP2014, or when its units are set to PNU.

*also available in ShareCG, DAZ, and HiveWire3D flavours (the DeviantArt and CGBytes flavour have been discontinued).