Hair Alpha

JoeMamma2000JoeMamma2000 Posts: 2,582
edited December 1969 in Carrara Discussion

Anyone know how to apply an alpha transparency to the Carrara Hair Shader? All I can see is the Wave and Frizz, etc., settings, but no Alpha

Comments

  • holly wetcircuitholly wetcircuit Posts: 0
    edited December 1969

    Try the length channel.

  • JoeMamma2000JoeMamma2000 Posts: 2,582
    edited December 1969

    Bingo !! thanks.

  • JoeMamma2000JoeMamma2000 Posts: 2,582
    edited December 1969

    Or maybe not...

    I initially thought the Length channel might be a sort of default Alpha channel, where you enter alpha information to define the length and it basically applied an alpha mask to simulate length. Apparently not, unless I'm doing something goofy.

    I basically want to define alpha using a alpha map, so I can either vary the transparency of each hair (maybe more opaque at the root where it's thicker, and more transparent at the tip where it's thinner...) or even apply a texture map to define the apparent shape of each hair (eg, a leaf or a feather).

    Any idea if any of that is do-able? Thanks.

  • ManStanManStan Posts: 0
    edited June 2012

    The dynamic hair doesn't use alphas at all. In the dynamic hair shader with the length and friz, an alpha map will be read like height or bump map. Dynamic hair does not have or use an alpha, it is individual strands of hair, so no need of an alpha.. These are all done with gray scale maps, not a duo tone alpha map, The hair bump map is more useful in those channels the an alpha map. An alpha is on or off, black or white, it takes a gray scale map; like a bump map, to set hair of different lengths, thickness{hairs per area} curl kink wave and so on. Yes, you can do a mullet with a distribution map in the hair length.

    I played around with this for a bit, logically you could use distribution maps to set your hair style, but I never could quite figure it out.

    Post edited by ManStan on
  • holly wetcircuitholly wetcircuit Posts: 0
    edited December 1969

    hair is scaled to 2.00 by default. Here it is scaled up to 70.00 (with 50 strands at 16 segments) and you can see it sort of resembles feathers. The hair "shaft" has 2 "wings" or "fins" that stick out per segment. These fins aren't real geometry, and when you rotate the model you will see the fins are like billbords that always face the camera...

    When it is scaled up like this you can apply various shader settings and use the various hair room tools, and really see what is happening to the individual hairs.

    Screen_Shot_2012-06-12_at_1.17_.55_PM_.png
    429 x 455 - 127K
  • JoeMamma2000JoeMamma2000 Posts: 2,582
    edited December 1969

    Right. And that's why I wanted to find some way to apply an Alpha map. I've already got the scaling (in fact I'm cranking mine up even higher), and I was wondering if I could then apply an Alpha so that the "billboards" looked like, say, feathers. However, the same idea applies even if you want to make your thin hair strands transparent, or vary transparency along the length.

    Bottom line, I guess as Stanley said, there's no way to apply any sort of transparency to the hair fibers.

    Thanks.

  • holly wetcircuitholly wetcircuit Posts: 0
    edited December 1969

    You might look at ANYTHING GROWS at Digital Carvers Guild. It allows tip objects with real geometry at the ends of strands.
    -
    I can't see the value of having clear hair strands, but "because I want to" is valid enough. There was discussion of making hair from "rags" with soft body physics. I imagine it would be something like ribbons attached in rows to a skullcap. A simple IK chain would also presumably work.

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