HD-geometry issues

system · July 4, 2019, 5:51am

I read in Version 3.5 HD-Geometry works fine for creating normalmaps, so i used them for my recent project. After finishing Sculpting and export of my maps, i see the resulting normalmaps are realy reaaaly bad (for example extrem jagged edges and other artefacts).

So i did some further testing and realised, maps extracted from HD-Geometrie are different, like seen in this image:

Why is that? Can it be fixed somehow? seems like Zbrush bakes the HD-Details as additional Bump into the normal-map?! This would explain the extreme jagged edges i have in my maps... Another Problem: I tried to convert (level 1) of my HD-Details into a normal subd-tool, but Zbrush wouldnt allow me to edit the whole mesh in HD-Mode, its just showing round about 1 million Polys in HD-Mode, ignoring whats set in preferences>mem>hd-preview-max-polys. Why is that happening? Can this be fixed somehow and or done another way? How can i save my work from "HD-Artefacts"? ...seems like i lost my work and I have to start over again.... sad, days of work lost.... :mad: Hope theres a solution i dont see....

system · July 3, 2019, 9:03pm

can I see the original low poly mesh?

system · July 4, 2019, 8:51am

@NoobVee: Lowpoly of this simple test (image)? It was just a simple plane…
Subdivided to level 6 for the upper and to level 3 +3 HD-levels for the bottom.

Heres another image from the my real project to compare the hd issues:

wondering why there are tris, poles and no even polyflow? Its for a game…

(for the record: i was able to save most of the sculpted details by cloning many different chunks of the HD-lvl2-mesh and projecting them back onto a mesh without hd levels, which is further subdivided)

Cheers

system · July 3, 2019, 9:03pm

is your low poly caged in HD?

system · July 3, 2019, 9:03pm

@NoobVee what do you mean with “caged in hd”… don’t understand…

system · July 3, 2019, 9:03pm

the hd must be as closed as possible in the low poly so you can generate a better normal map from hd. I think theres a way to fix this, if I can check your model.

system · July 3, 2019, 9:03pm

I just wanted to know why hd-geo is treated different than normal subdivisions.

Another question is: How is hd-geo saved? because the meshsize doesnt grow as exspected when using hd-geo. Is there just some kind of bumpmap stored internal for the hd-details? I ask this because i also had some issues with artefacts which became visible in the hd-geo after many times of saving and loading…

@NoobVee: i belive the problem isnt the basemesh, but the way hd-geo is baked into the normalmap.
Imagin you do some hd-detailing which is strong enough to project into your highest non-hd-subdivision, but that subD isnt dense enough to hold this detail. This will result in jagged edges and artefacts on the highest (non-HD-) subdivision, these jaggies and artefacts will be baked into the normalmap, but they shouldnt.
I cant change the lowpoly, because its meant to stay that low (i have to stay in a fixed polycount for later game engine export) and i dont want to retopo later cause this wastes much time.

My questions can only be solved sufficiently by the makers of Zbrush, but thanks for trying NoobVee.

anyway, i decided to not use HD-geo at all for my project because of these issues. Instead i split my model into some more subtools, which gives me a dense enough mesh to do my details.