Z-Brush displacement maps

[Adam H. Stewart]

Does anybody know how to get the correct settings for Vray displacement maps created with Zbrush. I have been using the Alpha depth value created by inside Zbrush and using it in the as a negative in the Shift slider to counteract mesh bloat but I cannot seem to get the balance right. Each model seems to require a huge amount of guess work to get it looking anyway like the Zbrush original.

Thanks as always.

[jacksc02]

are you using the vraybmpfilter?

[Adam H. Stewart]

I will give that a try

I haven't I'll give it a try - what does it do ?

[jacksc02]

from the help-
The VRayBmpFilter texture map is usually useful for displacement maps, created in external programs (like ZBrush, for example) where exact placement of the map is very important. The VRayBmpFilter map produces a smooth map by interpolating the bitmap pixels, but without applying any additional blurring or smoothing. This is not possible with the default Bitmap texture of 3dsmax.

[Adam H. Stewart]

I tried the VRayBmpFilter

I tried the VrayBmpFilter and it makes things worse, the same displacement settings that looked good with standard Bitmap gives me jagged spines when I use them with the VrayBmpFilter (using it's default sttings of .5 U and V)
I can't get to grips with the Vray displacement settings at all. Does the Suggested alpha depth in Zbrush have any bearing in Vray? It seems so hit and miss, I just keep punching in numbers until it looks right - there has to be a more science to it then that so frustrating

[Morbid Angel]

interesting, I also know of a different method, where one would export displacement map in format of *.map which has embedded model scale of the displ map. Then in any program the dislpacement amount is identical, i.e. we have tried this in maya and xsi.
The displ amout should be = displ 2.2 /shift -1.1, however in maya it came out inverted so we had to reverse the values but the actual number stayed the same.

[jacksc02]

there was a good thread a while ago about zbrush and vray displacement. do a search for it

[Adam H. Stewart]

Scale values in OBJ

I have figured out how to get the scale from the OBJ file how do I use this with the alpha depth to choose my displacement in Vray ? - is this used in conjunction with the Alpha depth ?

I'm getting closer


Thanks Again

[thablanch]

Actually, the scale of the base OBJ does not really matter, as it is the very same object that you imported from Z-brush.

You can ajust levels of the disp. map in photoshop, , less levels of gray.

z-brush tread
http://206.145.80.239/zbc/showthread.php?t=1126

[panthon]

You can always use the displace modifier from max to check the values in the viewport. When u are happy, u can copy this values to vraydisplmod. As a rule of thumb, Shift should always be half negative of the main value. In the zbrush forum they were always talking about the quick code to transfer displacement values directly from zbrush to max, but didn´t figured it out. If u have the time to look for it, it could be interesting.

[Adam H. Stewart]

A Riddle indeed

Wow - each thread I read over at the Zbrush forum leaves me more confused. It seems like there are hundreds of methods for calculating the correct Displacement and Shift values. There was mention of a script that automates the entire process, but one was never posted - what a tease !!

The Zbrush Codes seem to be connected with the new Displcament Exporter, which in theory prepares your maps for you, based on your application preset - but it only exports an image file(as far as I can tell), which does not help with the Vray displacment values which are based on scale factors in your Zbrush scene and your application scene.

I like the idea of using a max displacement modifier first to visually calculate the the dis. and using these values with the Vray modifier - I'll give that a shot next.

Thanks for all your patience and help with this.

[panthon]

Don´t forget that your displacement will be as good as your turbosmooth level can afford. So, it is directly proportional to your subdivision level. All this applies only to the standard displace modifier in max, and, to some extent, to vraydisplmod in 3d mode.

The cool thing about displacement values is that u can animate them. I saw a really cool animation with a werewolf showing the power of animated displacement. You can even connect them to morpher targets to create amazing automated effects.

You can check this cool animation by Patrick Beaulieu (www.squeezestudio.com) at:

http://www.zbrushcentral.com/zbc/sho...light=werewolf


Image by Patrick Beaulieu (www.squeezestudio.com)

[jacksc02]

woah, thats cool!