I’m using Max 8. I made sure to download Revision C of Displacment Exporter. I am following the online version of the ZPipeline guide for Max here:
http://www.zbrush.info/site/index.php/ZBrush_to_3ds_Max
This appears identical to, though larger than, the same dialog box screenshot in the ZBrush to Max pipeline guide.
I want to know why this looks different than it does when I am setting up to create a displacement map. I want to know why the alpha in the thumbnail is red here, and what the “Export Active Set” and “Export Current” buttons are available, and not grayed out as I always see them on my screen. Why is there a D32 button next to the R32 button on the top row? My screenshot for comparison. I seem to be following all directions exactly and yet there are differences. This wouldn’t concern me if everything was working as the guides said it should, but they don’t seem to be so I’m shifting into nit-picking mode.
From the Z pipeline guide:
For all 32-bit maps exported from ZBrush using Multi Displacement 2, the Extrusion Strength in Mental Ray will be the same; just set it to 220. However, if you didn’t go through MD2, you’ll still need to set the alpha gain based on the alpha depth factor from ZBrush
This is either wishful thinking or else something important was left out. My experience is that when extrusion strength is set much higher than 1 things can get ugly fast. A setting as high as 220 results in an explosion of polygon spikes.
I suppose this may be true in the test files they were using to write the guide, but they must have had some special scene file scale.
As far as I know 3DS Max defaults to generic units to describe the size of a scene, but when you type in a length like so: 12" you get an object 12 units long. So 1 generic unit = 1 inch. What base scale were they using? And how do I make sure that my scene scale in Max matches up with the scale of a displaced feature from ZBrush?
Another thing that bothers me at this step of the process is that we are using a shader component called “3D Displacement” And as we can see in the options shown in the tutorial screenshot this is opposed to “Height Map Displacement” Why then does the resulting displacement not seem to deform the surface in 3D, but in the direction of the surface normals only?
What I was expecting here was for the high bit depth displacement map to act something like a normal map, with colors that gave direction information and an alpha channel that specified magnitude, but it neither looks like a normal map nor displaces in 3D.
What is the direction map slot for? I tried putting the 16 bit map in that slot and using a direction strength value of 1, then 10 then 100, and it didn’t seem to help, so I swapped the maps and tried them again. I didn’t see how that helped me so I went on to try other things. Does ZBrush have any features that would help someone take advantage of that map slot?
More about where I am:
My screenshot showing all settings and the render when using displace subpixel 2, with Mental Ray and mapping coordinates created in max. (symmetrical) A strange folding artefact visible in the lower right of the render.
My screenshot showing all settings and the render when using the displace modifier to render in the scanline renderer. Exact same mapping as in the screenshot above but major artefact visible down the center of the object. inexplicable.
Some of the render times are visible in the screenshots, Don’t read too much into them though, my machine is quite old.
Any information that can help me improve my results would be greatly appreciated. There are enough little settings that I can hope for someone to tell me about something little that I’m missing. Right now though displacement mapping is starting to look like a bit of a kludge when compared with normal mapping.
Images hosted by Flickr.
