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rdolishny
02-19-2013, 08:57 PM
How do I create a patch of long hair for hair, and a patch of short hair for eyebrows?

I think I have my weight maps set up right: I can do one or the other but not both. I want to change the length of the eyebrow hair to be really short, but keep the head of hair nice and long. The picture attached shows the bushy eyebrows I'm not liking. 111732

Greenlaw
02-19-2013, 10:37 PM
If you're using 11.5, you should try Edit Guides. To do this, create a surface just for the scalp and eyebrows and click Edit Guides. Don't worry about getting the exact shape of the boundaries--you can control the exact shape of the fiber area within this surface using a mask for fiber density. Naturally, this is easier to do if you've already prepared a UV map for the head. With Edit Guides, you can edit the lengths of guides in different areas of the scalp or eyebrows using the Scale brush.

Bonus notes for using FiberFX Edit Guides: I've run into some occasional weirdness in network rendering with Edit Guides but in general, it's very useable now. One trick to using FiberFX is to make sure you 'set' it at the beginning of your scene on an un-deformed version of your character--this is true for any usage of FiberFX but it's easy to forget that when using Edit Guides since it technically allows you to comb and edit the guides at any frame. The idea is similar to why you must 'rest' bones in a rig on an un-posed mesh before you can animate it. In the case of FiberFX, pick the frame where you want to edit and always use that same frame for editing, especially if there is any animation or displacement in later frames--my suggestion is to pick frame zero and start your animation at frame 1 or much later downstream (like frame 100) if you're also planning on using Bullet or other dynamics with this character.

Alternatively, you can use externally modeled guides like ZBrush FiberMesh, Strand Modeler, rail cloned or hand placed guides. The advantage to using external guides is that they can be styled more precisely than by using Edit Guides. The disadvantage is that they're harder to UV map and you need to bind the guides to the character's skin. I find that the third party tool DrainBGVMap works very well here for conforming root points to a character's existing UV map for texturing the fibers (this is more significant for creatures with textured fur, like a zebra or tiger, for example.)

To bind the guides, you will also need to weight the guides for bones either with DrainBGVMap, which can transfer existing character weights to the guides--otherwise brute force weight creation for the guides manually, or use FX_Metalink to attach them to the skin, which will required pre-scanning with ClothFX to work properly. (BTW, there is a new nodal version Metalink available in 11.5, which should have been ideal for this sort of thing since it doesn't require ClothFX but unfortunately the current release of this tool doesn't work with subpatched geometry. I hope we'll see an update to this promising tool in a service pack soon.)

Good luck! I hope this info is helpful. :)

G.

UnCommonGrafx
02-20-2013, 04:02 AM
Or weight maps might help.
10% on the eyebrow area, 120% on the head hair area, -120 on everything else. Oh, maybe a 20% beard, for stubble and the like.

rdolishny
02-20-2013, 05:43 AM
That's what I thought, I have two weight maps: hair, then eyebrows. But when I add the two gradients using the weightmaps as inputs one cancels out the other.

I am experimenting with blend modes but I'm not sure what I'm doing, in particular if the order of operations matters. Here's a UI frame.

111740

The top (active) weightmap is 'hair'. The bottom (currently inactive) is 'eyebrows'.

rdolishny
02-20-2013, 05:48 AM
Thank you for this thoughful and detailed reply. I'll look into edit guides, although I think I'm very close to understanding multiple weight map gradients once I figure out Blending Modes and order of gradients with blends.