Hi Andi,
A tangent map is the space in which a normal map is stored. It provide
a local space at every point on the geometry. Where the normal is the
Y axis, the U direction of the UVs is the X axis and the V direction
is the Z axis.
So it's like a custom local space for every location on the mesh. It
allows you to do things like define points relative to that location.
In terms of displacement it's one way you could have multi-directional
displacement which holds up with envelope deformation on the mesh.
In bump-mapping I haven't really thought about what you'd use it for,
but I'm sure someone will throw a good idea out there. Because a
bumpmap modifies a normal - you can save that new direction in tangent
space and this gives you normal map. Which you can use in substitution
for the bump map. It'll be faster to calculate because it requires
only a single lookup as opposed to a bump map which would require
multiple samples to figure out the change in direction.
Cheers,
Alan.
On 1/24/07, Andi Farhall <andi(at)clearpost.co.uk> wrote:
actually i'm a bit confused as to what a tangency map is. I understood tangency to be where one curve flows cleanly into another, either that or "at 90 degrees to". I'm wrong aren't i....
Subsequently i've no idea how you would use them in the context of displacement or bump mapping... boy do i feel thick
regards
Andi
-----Original Message-----
From: owner-xsi(at)Softimage.COM [mailto:owner-xsi(at)Softimage.COM]On Behalf
Of Bernard Lebel
Sent: Wednesday, January 24, 2007 12:08 PM
To: XSI(at)Softimage.COM
Subject: Re: tangent maps
Bumpmap and displacementmap substitution, we do a lot of em.
Cheers
Bernard
On 1/24/07, Andi Farhall <andi(at)clearpost.co.uk> wrote:
>
>
>
> Do have tangent maps have any other uses apart from hair instance
> orientation? without scripting stuff that is...
>
>
> regards
>
> Andi
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