Ugly indeed. The bumpmap implementation in XSI never ceases to amaze me...
MB
----- Original Message -----
From: "André Adam" <a_adam(at)49games.de>
To: <XSI(at)Softimage.COM>
Sent: Thursday, December 07, 2006 1:16 PM
Subject: Re: Bump Mapping and Camera Projections?
The job of the bumpmap generator node is to apply a heightmap (grayscale
bump image) to the object's topology and to calculate a new set of normals
based on the combination of heightmap and geometry. The result is a normal
map in object space, you can display it when plugging the output of the
bumpmap generator directly into the surface input of the material node.
This conversion from heightmap to normal map is essential to make the
effect work correctly and cannot be provided through the image node when
plugged to a material's bump input.
The image node, however, features a bump switch, which creates the normal
information just as the bumpmap generator does, but it only gets carried
along with the image node's regular colour output under the hood, not
visible as a connection in the rendertree. Workflow would be to block out
the colour of the heightmap image using a mixer node and connecting the
mixer to the shader's diffuse and ambient inputs. This way the bump
information is used during rendering without display of the heightmap on
the object's surface. Ugly. Basically how it used to work in SI3d, if I'm
not mistaken...
Cheers!
-André
Morten Bartholdy wrote:
Well I never used camera projection for bumpmaps so it is not exactly
part of my workflow. i usually use Zbump or plug BA shaders directly into
the Surface bump input, and almost never use surface shader bump inputs.
Forgive my ignorance - I didn't know it would produce wrong results this
way - could you enlighten me?
Morten Bartholdy
3D & VFX Artist
----- Original Message ----- From: "André Adam" <a_adam(at)49games.de>
To: <XSI(at)Softimage.COM>
Sent: Thursday, December 07, 2006 11:37 AM
Subject: Re: Bump Mapping and Camera Projections?
Bah, bump mapping through image nodes is such an ugly thing to do.
Btw, you don't plug your image node directly into a bump input, do you?
That would give plain wrong results...
However, thanks for the feedback!
-André
Morten Bartholdy wrote:
I see the same thing here André - don't know if I'm doing it wrong
either though ;)
Workaround would be to plug your image node in to the bump input of the
surface shader. It limits your options but works.
Morten Bartholdy
3D & VFX Artist
----- Original Message ----- From: "André Adam" <a_adam(at)49games.de>
To: <xsi(at)Softimage.COM>
Sent: Wednesday, December 06, 2006 4:59 PM
Subject: Bump Mapping and Camera Projections?
Hi all,
I'm currently trying to reference a camera projection as a texture
space for a bumpmap generator node. Doesn't seem to work, at least I
can't spot any piece of bump mapping. If connected to an image node,
the texture appears on the object's surface as expected. Is this some
kind of limitation of the bumpmap generator node or is it me doing
something plain wrong?
Cheers for a quick hint!
-André
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