Maya/Arnold displacement maps in both positive and negative values

BobbysWineGums

hi,
im quite happy using UV displacement maps to eventually bake on geometry, mainly embossing on objects or engraving. 
What I really want to know is if it’s possible to create both in the same displacement map and if so, how? The resulting files are typically HUGE so no hope of bringing a post-baked mesh back into Maya.
I’d heard it might be possible to set the ‘0’ value to say 50% grey then darker will be negative and lighter positive but I’ll be buggered if I can find out how. I’ve only been using Maya for a year and displacement maps for a couple of months so be gentle!
A thousand and one thanks to anyone who can help, you lovely people!
Dan

oglu

32bit dispmaps do that out of the box. Black is zero and negative values push inside.

If you use 8 or 16bit you could move the center with "zero value". 


https://docs.arnoldrenderer.com/display/A5AFMUG/Displacement?desktop=true&macroName=multiexcerpt-include

BobbysWineGums

Thanks
So to set the zero at 50% grey? Where do I do that?

oglu

Set scalar zero value to 0.5
Like in the docs i posted. 

musashidan

oglu said:

Set scalar zero value to 0.5
Like in the docs i posted. 

I don't think people learning 3D these days even know the docs exist, perish the thought of actually reading.

oglu

I get the same feeling. 

BobbysWineGums

Perfect, thanks. I’ve read this exact document a couple of times but never managed to fully decipher it. I tend to find the official docs assume an understanding I don’t have yet, especially in the language of the program. It’s obviously been staring at me in the face without me realising it was the answer! 
Thanks very much for pointing it out, much appreciated.