ZBrushCentral

Z2 Displacement in Max

Was worried for quite some time about how well Zbrush 2.0 models & displacement maps would work when exported to 3DS Max 6, but happily it looks like all works quite well! Thought I’d share a quick render:

This was with Vray, which works spectacular for rendering displacement by the way. Been experimenting a lot with displacement maps in Mental Ray too, but it just can’t cut it unfortunately (may work better in Maya though, I wouldn’t know) and this test was no exception. GUV tiles were used for the UV mapping and the object was exported at div level 2. I found level 1 caused a couple tiny anomilies in my render that couldn’t be tweaked out, so that’s why I went with level 2 and just used less subD on the poly model in Max (better performance overall too).

Must say I’m pretty impressed so far! This is really going to bring models to a whole new level. Now off to dig deeper… :slight_smile:

Hi zeddicus

Out of interest, how did you manage to get both positive and negative displacement out of vray? In my experience, vray/max interprets black to white in disp maps as 0% to 100% displacement, with no negative range.

I’d be very grateful if you could post your VrayDisplacement modifier settings and maybe a shot of the disp map you’re using.

thanks in advance

Nothing fancy at all really. After importing the OBJ file and converting it to a poly object so I could turn up SubD Surface iterations a couple notches, I just threw the VrayDisplacementMod modifier onto it, set that to 3D mapping, loaded the displacement map (a 16-bit TIF file) from Zbrush as the Texmap, set the amount of displacement I wanted, and rendered. Default Max settings all around for the most part. The object is from the displacement map tutorial. At the end of chapter 4 it asks if you want to save everything to file so you can play with it, so that’s what I did.

Hey, I think your right. I’m new to Vray and I didn’t realize it worked the way you stated, but after going back and comparing displaced vs non-displaced renders in Max, I can see that the middle grey added an overall “bloat” to the model, while black areas on the map only look like negative displacement because they weren’t displaced at all relative to the middle greys. Still, if you were careful about the middle grey, you could probably get away with faking the negative displacement as I did by accident. Hopefully Vray will be updated to do both negative and positive displacement properly, like the way Zbrush does it.

hi,
i have tried out the same last night using mental ray, finalrender stage 1 and the 3dsmax scanliner. with all those renderers i have those “holes” in the displacement. unfortunately i dont have vray. gotta test out more since i believe there must be a way to do it right in mentalray.

all the best,
daniel

Well, I tried to lay down and get some sleep (been up all night lol). I was struck with the idea of using two maps, one for positive displacement and one for negative, and using two of Vray’s displacment modifiers instead of just one. Editing the Zbrush displacment bitmaps was easy enough. For the positive map I simply adjusted the black output level to 127 using levels is Photoshop. This left only the positive height values. Then for the negative map I simply inverted the Zbrush bitmap and then did the same levels adjustment to it as well, thus leaving only the negative height values. Only problem was that Vray will only use the modifier at the top of the stack and not both. Too bad too, because by themeselves, both my positive and negative displacement maps worked good. :-/

Here is to hoping Vray gets updated because I really love it. Simple to use, fast, powerful, and so far has handled everything I’ve thrown at it without any trouble what-so-ever. Anyways, using a middle grey as the zero point instead of black makes the most sense to me. Doesn’t make any sense to be able to do only one or the other but not both.

triztan: Definitely give Vray a try. Nothing does displacement better as far as Max is concerned. They have a trial you can download, so you might want to give that a go. :wink:

hi, did you notice the SHIFT AMOUNT spinner
just below the DISPLACEMENT AMOUNT? You don’t
have to use seperate maps to archive positive and negative displacement in vray.
If you set the shift amount to a negative value, approximately half the displ. amount, black areas are pushed in, just play around and figure out which values do it.

I got another question, did anyone here try to sculpt a high detailed model like the ones from WETA or those on the zbrush2 homepage?
It seems that I have a performance problem. To archive this level of detail with little skin wrinkles etc. I have to divide my models
several times until the poly count is about
5millions or so. Then zbrush gets so slow that working with the freehand sculpting tools is impossible. I got 2.5 GHZ and 1GB ram.
Or is it something with my workflow, do I have to use the projection master tool instead?
I bought zbrush to use it for a film project
I work for ( see www.soulfire.com and now I question myself if I can really use it.

Rocko,

have you tried using the Ctrl+Shift Drag Window to work on selected areas?

That speeds things up a great deal.

Cheers,

Steve

ZBrush is also capable of exporting separate positive and negative maps.

Select your displacement map in the Alpha palette and open the AlphaAdjust Curve.

Click the Load button and load the NegativeDisplacement.ZCV

Click Alpha>Make Modified Alpha

Now load the PositiveDisplacement.ZCV and click the Make Modified Alpha button again.

You will now have three displacement alphas: The original map, a negative map, and a positive map.

Have fun!

that’s what I have found so far to use with Vray

export displace map from ZB as Tiff file
export object at sub division level 2
in max
Place a meshsmooth modifier otherwisse the displacement modifier explode the object

Set an amount of displacement
set the shift value to half oposite
( example amount 10 shift -5, amount -22 shift 11…)

In material editor rotate texture 180 in W and -1 in x tile

hope that help

zeddicus i have problems with uvw importing max. It ends zigzag. Can you help me a little?

Does max 6 directly import OBJ files? If not, how did you get it in max? I’m using max 5.1 and it doesn’t have an import option for OBJ files.

You can use the freeware plugin Habware Max to Obj and Obj to MAX to get in and out of MAX 4 , 5 & 6.

Probably find the link on scriptspot.

Just got here from the Vray forums where negative shift with positive displacement was explained to me. Supposedly there is a random bug when doing this by the way. Regardless, so far so good, works well in this particular case. Thanks to all who replied. :slight_smile:

Also, if you flip the map in Zbrush before exporting, you won’t need to alter the coordinates in Max as Junk has pointed out. Also as pointed out, displacement does work better if you export the model at divide level 2 in Zbrush and use that in Max. In fact I’ve found that going one level higher than the lowest in Zbrush means you can use up to two subD levels less in Max, making for better performance all around.

Aurick: Thanks for pointing out those scripts. Saves having to go into PS to do it and will hopefully help anyone who needs it, though in my case with Vray it didn’t work (can’t use two maps as mentioned earlier). But luckily thanks to the comments from other Vray users, this has been solved. :slight_smile:

blakshep: See my reply to your other post regarding the zig zag. Hope it helps you.

rocko: There is a page where someone has done some amazing displacement work using ZB2 and Vray (guy who did troll holding bunny). Just need to find it. Will post when I do.

Here is the Obj2Max and Max2Obj plug-ins:

Max 4 & 5: http://www.habware.at/duck4.htm
Max 6: http://www.habware.at/duck6.htm

And here is the site (belongs to Jonas Thornqvist) with a couple ZB2 models rendered with Vray:
http://www.subdivme.com/

Specifically this:
http://www.subdivme.com/Wip.htm

And this:
http://www.subdivme.com/Troll.htm

Pretty sweet eh? :slight_smile:

PS: Here is the thread on CGTalk regarding the troll:
http://www.cgtalk.com/showthread.php?s=&threadid=123173&highlight=cave+troll

thanks for all the vray info everyone

one thing though - did anyone resolve the issue of banding artifacts in displaced geometry as noted by Zeddicus in the thread at the base of this post.

It would be handy to know under what conditions the banding occurs - just using 16 BIT TIFs doesn’t seem to clear it up.

cheers
banding thread

brushoid: With all the testing I did in the thread you mention, I really do think that the problem is unique to low poly spheres (or maybe spheres in general) and the effect subdividing has on them. Basically what is happening is that the surface does not stay perfectly smooth each time you subdivide. The polys that make up the sphere have a tendacy to “buckle” for lack of a better term, and tend to do so uniformly (which is probably why those renders look the way they do, like a contour map… moire or interference pattern perhaps). With spheres that have two poles, the buckling seems to happen along the lines of longitude. With a geosphere, the buckling is quite different. More like ripples in a pond, but square instead of circular and on four sides of the geosphere. There may be more to it than that (I don’t really understand the mathematics involved with 3D computations, I’m an artist and not a programmer lol), but so far other objects, like those made from Zspheres within Zbrush, don’t seem to exhibit this problem.

is it your site posted before Zeddicus?

nice stuff here

Fouad: No, that wasn’t my site (I wish!). It belongs to Jonas Thornqvist as I mentioned in my previous post. :wink: