ZBrushCentral

One Displacement Map on Many Objects?

ZBrush Usage Questions
#1

Hi there,

Got a question some of you might know the answer to.

I have several small objects that I want to displace, which are laid out in the same UV space for the sake of efficiency. I initially thought I could use a 16 bit displacement map for all of these objects, sculpting each one seperately in Z, exporting each map and then combining the maps in Photoshop and exporting as a single image. It was my theory that the single image would then properly displace all the objects (small skulls of varying shapes) properly, even tho the objects were separate .

However, I found this not to be the case. When I combine several TIFF exports from Z into a single 16 bit grayscale TIFF from Photoshop, the displacement doesn’t work correctly on all the objects in the scene. I can get one object to displace fine, but the others are smooth.

Any ideas? How do you handle multiple objects in the same UV space with displacement? One workaround I found was to line all the objects up like a totem pole so I could use the X:Mirror Transform feature in Z-Brush, then I just hide what I am not working on. This works, but it seems I should be able to work on each object separately using the same map?

Ideas are welcome.

Thanks!

#2

16-bit displacement maps require a scaling factor, which can be determined using the Alpha Depth Factor. This value is going to be different for every object, however.

To avoid having to use a depth factor, you should create 32-bit floating point maps. Displacement Exporter can do this, via the Multi Displacement 2 feature that comes with the DE plugin. There’s documentation included with the download as well.

#3

Thanks for the reply, Aurick. I’ve had terrible luck with 32 bit displacement maps, even following the techniques posted here and using the DE plugin and Mental Ray and all that. Whether it’s work or home, I just can’t bloody get it to work.

So, I’ve stuck with 16 bit for now and it seems to be working out ok.

Right now I am just exporting various objects using one UV map into Z together…then I just hide what I am not sculpting…seems to work well for multiple objects using the same displacement map.

#4

Anyone have any ideas regarding this? How do you handle multiple objects sharing one UV space?

I suppose I could export smaller maps for each object individually, or one large bitmap after working on each item separately, or work with a totem pole of objects so I can use mirroring and detach them later…

How do you all do it?

Thanks…

#5

hey dan, just an idea not sure if it will work but what if you make different shaders for each object in maya… like one blin for each and then add the displacement file to each shader seperatly

#6

hey dan, just an idea not sure if it will work but what if you make different shaders for each object in maya… like one blin for each and then add the displacement file to each shader seperatly
Thanks CG…I think for now I’ll just work on the objects in place if I need them to share a displacement map…at least until there’s a better way to do it (or until 2.5 comes out!) :+1: