ZBrush Hair Card Basics

Nov 26, 2020 at 06:00 am by Warlord720


ZBrush Fibermesh is a powerful option for easy, low poly, hair card creation. Like everything else I write about it’s not magic, it just takes a grasp of the basics to get started on your journey to custom hair without crashing your pc over a heavy polycount.

My last mention of Fibermesh brought more questions (it usually does) with an overabundance of questions from people just getting started with it. To some ZBrush wasn’t new but Fibermesh was and to others, both were new and mysterious.

The concept is easy enough. Just draw a mask over the area you want to have hair and press the preview button. Then you could go into a modifier menu to control how you want the hair to look. That part is indeed easy enough but the problem to hair newbies was the amount of fiber generated by default, the way it looked (thin, long, and somewhat unruly), combined with hair going everywhere created massive information overload.

Looking like fibers instead of cards compounded the confusion for some. Not knowing the modifier panel made it worse for others as ZBrush can be more than a little cryptic with descriptions of the UI. Seems several just stopped here while others tinkered a bit (groping around the dark is more like it) before hitting the Accept button to get results.

Most eventually hit a roadblock and gave up. That frustration is not unusual with higher-end applications. There are so many things to do in a 3D model that we move on to other things to keep the creative juices going. Rightly so, but many don’t realize how close they are to creating transparent hair cards that can render out nicely… even in real-time.

So, let’s take a quick, no-frills, dive into changing those default fibers to usable hair cards with proper UV mapping. We are not going to get into grooming (good luck with that… just don’t give up) as that could take up volumes but we will take a quick look at getting started. I will only be doing a couple of segments on the model’s head so we can see what is going on with the underlying mesh.

In this case, I’ll be using the default female from Character Creator 3, but any character mesh will work.  CC3 allows me to use the time-saving GoZ function and is my choice for custom character bases.

In the picture below you will see CC3 mesh with the scalp area divided up into subsections via poly groups. This division is not arbitrary but based on working with parts of the scalp instead of the entire scalp area to match length and other aspects more easily. This is a simplified version as you will develop your own grouping to suit your workflow. You will immediately notice the unruly appearance of the default fibers.

Default Fibermesh
Default Fibermesh From Masking the Bottom Two Sections of Scalp

 Going into the modifier panel and changing some settings we can reduce the amount of fiber needed by reshaping the fiber with the controls provided. This is a simple manner of setting things like revolve and twist to zero. Setting the gravity slider all the way over to 1 and changing the gravity profile to where it fills the window area.

One of the most important parts of this technique is the opacity map that defines the final look of the hair cards. When rendered they go from flat cards to hair fibers via opacity.

Opacity Maps
Alpha masks are a very important part of this technique.

 

Match the menu settings you see in the last image to go from the default thin fiber-looking mesh to a more traditional hair card type of mesh. What I’ve done is widen the root and tip to one. Then upped the COVERAGE to max (which actually widens the strips) after you’ve taken out twist and rotation. I used the GroomHairLong brush for a simple brushing. Also, note MaxFibers is set all the way down to one. Combined with Coverage this is another important part.


Rudimentary Brushing and BPR Render Result

 This is just enough to get you started down the road to creating your own hair. As you see the Opacity map is the key and mesh will not look like hair until you apply it. Fibermesh settings are below.

 


 

M.D. McCallum, aka WarLord, is an international award-winning commercial graphics artist, 3D animator, published author, project director, and webmaster with a freelance career that spans over 20 years.  Now retired, M.D. is currently working part-time on writing and select character development projects. You can learn more about MD on his website

 






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