Hey guys,
I was wondering if there is a way in ZBrush 4 to create a cavity or AO map from HD geometry. I’ve searched around and found this asked a couple times before but haven’t seen any answers. Is it possible? Or if not is there a good workaround to get a similar result? Thanks.
For a cavity map you probably don’t need the super fine detail that’s in the HD. So in that case you could create a displacement map, then apply that to the non-HD mesh and convert it to geometry. From there you can create a cavity map.
If you do need the fine detail, after creating the displacement map split the model into parts so that you can divide the SubTools individually to get a polycount equal to the HD model. Apply the dispmap to each, create your cavity maps, then combine them in Photoshop.
Thanks for the info aurick. 
The reason for wanting to use HD geometry is mostly performance based. I have better performance with a mesh subdivided to around 250k-1mil polys and HD as opposed to just subdividing the model to 15mil+ polys. A lot of the details (small scales ect.) require lots of geometry to sculpt and look good. I’m working for mobile game assets so I’m only able to use color with AO and cavity baked in to make the details pop.
Its a bit disappointing you cant bake out those maps from HD geometry as that would be really convenient for my current workflow. Well, something to work on for the next point release eh? 
Simply split the model into multiple SubTools to isolate the areas that need the greatest detail. You’ll then be able to use regular subdivision levels to sculpt the details that you’re after.
A model broken into four equal SubTools can be divided once to have the same number of polygons that an HD level allows. You will still be able to work smoothly with the model as well, because ZBrush focuses the majority of its resources on the current SubTool, only.
Good point.
My concern with going that route is that I tend to get carried away and sculpt right up to the edge of my subtools and get seams. 
Still, I think your solution might be the best way to go.
Best way for now, yes. But Aurick, I agree with the ninja. Being able to generate a cavity map from HD geometry would be MUCH more ideal than some convoluted work-around. It would be great to add this feature to the list; seems very practical.
If I’m using HD geometry to generate pore/wrinkle details on a character’s face, I’ll want to generate a cavity map to use on my diffuse map. That’s just the first example I can think of.
When I’m using ZB or any software on production, it’s nice to know about these work-arounds but they’re always a time suck and a pain to deal with. They cause me to look to other software (i.e. Photoshop) to get the job done b/c I don’t want to spend the time posting to ZB Central and waiting for a reply that may or may not come. That being said, ZBC is great and for the most part, replies are plentiful.
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