ZBrushCentral

Rendering Zbrush Displacement Maps in Maya

Crossposted - sorry : ) It maybe should have gone here instead of the other forum.

Hello All,

I made a quick video walkthru on rendering the Pixolator test head in Mental Ray. It is a rundown on the settings I use to get good renders and I hope it might help some others in the community.

It isnt the end all of approaches but what I found works well and helped get me started with using Zbrush and Maya together.

Download here
The movies are quicktime and compressed in zip archives

LARGE 26 MEG QT

MEDIUM 18 MEG QT

SMALL 6 MEG QT
screen.jpg [Icon200.jpg[/attach]]]([attach=11026)

Attachments

Icon200.jpg

As mentioned before: T H A N K YOU!!!
very much

First thread was thank you for the time and effort spent in trying
to help those of us that have problems in this area.
Have done a few searches over the past few days and noticed that this is not the first time you have tried to help others with this topic.

Have downloaded and watched.

Recently I, as well as a few others, have spent some money on professionally
made tutorials that relate to various subjects ( no names)

I would have to put the job you have done here right up with the best.
The primary thing I noticed is your clarity of explanations.
Professional job. Not a wasted sentence.

My girlfriend who knows nothing about this, asked me"how much was that
one?".
When I told her she made a comment I thought I would pass along.
“he should sell them”

He should.

Feel very sorry for 3d max, xsi,cinema, truespace etc. They don’t have
Scott Spencer to guide them.

Thank you again.

thanks for the video, realy help to understand mental ray settings :+1:

bicc39: hey man, thanks for the kind words Im glad it helped : ) I was hoping the explanations were clear, I plan on making more of these for other aspects of Zbrush as time permits. As for selling : ) naw it was like 30 min of time and I only know how to do this cause other people helped me on the forum here. believe me if you are pulling yer hair out I was right there with ya not too long ago.

joss3d: Thanks too. Im glad it helped you! : )

Scott

thank you so much. I’ve spent the last few days fighting with maya over the sword file.

“Feel very sorry for 3d max, xsi,cinema, truespace etc. They don’t have
Scott Spencer to guide them”

Damn right…and thank god…

Over and Out

*8

Thanks Scott Spencer!

Could anyone give me the alpha offset expression here? I probly got it wrong. Thanks a bunch.

Thanks again everyone, glad its helping.

The Alpha Offset expression is written as follows starting with the = sign and replacing filenodename with the name of the file node (it is at the top of the attribute editor window, usually its file1 or another number) note the negative sign too.

= -filenodename.alphaGain / 2;

example:
so for a file node called file1 this expresson reads

= - file1.alphaGain / 2 ;

Major thanks to Sunit who first exposed me to this expression in his thread at http://www.zbrushcentral.com/zbc/showthread.php?t=22176

Also note that the alpha gain number will be different per each map you make in zbrush. Usually I dont use the alphaDepth factor from zbrush at all but it is still worth noting just in case.

Scott Spencer

I just want to say thank you so much for spending the time to make this video. I love the power of zbrush so much but I could not understand how to get the displacements correct in maya, even after watching you demo at the maya user group meeting. I asked for help here and you and the mod were the first to help me. True there are many tuts here but there is nothing like a video I can study over and over again.

Thank you for the video and thank you for your help at Monty

Mastershokhan ( Dred-guy)

The doors you have just opened for me…

thank you again

:+1: :+1: :+1: :+1: :+1: :+1:

Thanks for sharing this. I’ll definitely be looking into this in a few weeks. :cool:

cool :+1:

something that might help with the hair pulling.:smiley:
you do not need a displace approx when using a subdiv approx. to test that out. after you have your model tuned – disconnect the disp approx. this is as of maya 6.0 i believe – definitly in 6.5… cheers

Cant get any better then this… just to put the effort in making a video tut… is extreamly helpful, for someone like me… who knows nothing about zbrush… been having a hard time intergrading these technique with other apps.

ps: your work (website) has inspired me to get back into 3D.

to clearify what i posted about approx settings: when you attached a subdiv approx, mental ray will ignore any displace approx attached to the mesh. that can be confusing if you’re tuning and don’t relize that (i’ve pulled my hair out on that one:D )-- just use subdiv approx.

Right on, good call. The Displacement Approximation is not correctly implemented in Maya as of 6.5 sccording to the Mental Ray guru-dude at work. I should have noted that in the video. It also apparently cuts down on render
times to remove it in a lot of cases.

He submitted a bug report to Alias and Mental Images. Perhaps this will be fixed in the near future.

Thanks for posting it here : )

Scott

here’s an excerpt of a mental ray user group email:

If you’re using 3.3, the sub-d tesselation and displacement are now all done in one step for improved precision. There is no longer an approximation pass, and then a displacment pass. You just need to crank up your approximation values - the displacement ones aren’t used.

j
----------------------------- From: “jason bright” jason_bright@hotmail.com

please post if ya get an answer from mentalimages. it would be intereting to see wether this is a bug or how it’s intended to work. not sure if this person works for MI. MR3.3 = maya 6.0

rock on:+1:

According to my experiences, zbrush does not output images which are exactly 50% grey at zero displacement… measure the graypoint with a colorpicker (I use the one in DFX+) and incorporate that in your expression, if you can push alpha gain way up, and still retain zero displacement where there should be none you’re home free.
To test this I have a copy of the undisplaced geometry at the same position as the displaced mesh with a radically different color, when you see the polygons “fighting” to be seen in the renderer all is well.
Just my 5c.

Hey Matt Thanks for the update from the list! I will let you know if theres an answer. I would assume its a bug sine the menu is still active and there is nothing to clue you in it has no functionality (including the documentation). I will post more info as I get it.

zkanal: Sounds like a good way to rendertest. What do you mean by “:fighting” to be seen tho? Can you maybe send me a screnshot or post one here?

Thanks all,

It looks the same way as if you would have two identical poly objects in the viewport , one which is grey, and one which is red, when you tumble around you will see the polygons shimmering as they have problems deciding which poly should be visible.

I always do this to make sure my settings are 100% correct, and that there is no displacement at 51,6% grey (or whatever gray value zbrush outputs, which in my experience is different on a per object basis)…