On Fri, 27 Oct 2006 09:20:57 +0200, TB Software Support
<NOS### [at] tb-softwarecom> wrote:

>
>Displacement mapping (or bump mapping) is already supported in
>POV-Ray.
>

Bump mapping in POV-Ray affects the normal of the object and does not
actually displace the surface of the object.  For example, if you use
a strong bump map on a sphere, you will notice that the edges of the
sphere are still perfectly round, as is the shadow cast by the sphere.
Displacement mapping, in the context that I am referring to, would
actually perturb the surface sphere.  This surface perturbation would
affect the shadow of the sphere also.  The effect would be similar to
using an isosurface in POV-Ray.


Kyle

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Kyle nous apporta ses lumieres en ce 27/10/2006 14:17:
> On Fri, 27 Oct 2006 09:20:57 +0200, TB Software Support
> <NOS### [at] tb-softwarecom> wrote:

>> Displacement mapping (or bump mapping) is already supported in
>> POV-Ray.


> Bump mapping in POV-Ray affects the normal of the object and does not
> actually displace the surface of the object.  For example, if you use
> a strong bump map on a sphere, you will notice that the edges of the
> sphere are still perfectly round, as is the shadow cast by the sphere.
> Displacement mapping, in the context that I am referring to, would
> actually perturb the surface sphere.  This surface perturbation would
> affect the shadow of the sphere also.  The effect would be similar to
> using an isosurface in POV-Ray.


> Kyle

And would probably take around the same amount of time to render as an isosurface.

-- 
Alain
-------------------------------------------------
SHOPPING MATH
A man will pay $20 for a $10 item he needs.
A woman will pay $10 for a $20 item that she doesn't need.

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In article <45426f8a@news.povray.org>, ele### [at] netscapenet says...
> Kyle nous apporta ses lumieres en ce 27/10/2006 14:17:
> > On Fri, 27 Oct 2006 09:20:57 +0200, TB Software Support
> > <NOS### [at] tb-softwarecom> wrote:
> 
> >> Displacement mapping (or bump mapping) is already supported in
> >> POV-Ray.
> 
> 
> > Bump mapping in POV-Ray affects the normal of the object and does not
> > actually displace the surface of the object.  For example, if you use
> > a strong bump map on a sphere, you will notice that the edges of the
> > sphere are still perfectly round, as is the shadow cast by the sphere.
> > Displacement mapping, in the context that I am referring to, would
> > actually perturb the surface sphere.  This surface perturbation would
> > affect the shadow of the sphere also.  The effect would be similar to
> > using an isosurface in POV-Ray.
> 
> 
> > Kyle
> 
> And would probably take around the same amount of time to render as an is
osurface.
> 
Though.. Are there not some basic limitations of Isosurfaces as well 
anyway? How do you use an isosurface to produce a car or an animal 
model, for example? The one advantage displacement maps have is that you 
can add geometry to an object that "isn't" easily defined with a clear 
concise algorithm. If that is a good reason to support such a thing or 
not is entirely a matter of various people's perspectives of course. Its 
not always possible to argue successfully for solution that make things 
easier to do in "specific" cases, when there is a perception of a more 
physically "correct" model already in the engine, and it just happens to 
be complicated, frustrating and confusing to get the same result with it 
(like subsurface scattering effects, for example).

-- 
void main () {

    call functional_code()
  else
    call crash_windows();
}

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Patrick Elliott <sel### [at] rraznet> wrote:
> Though.. Are there not some basic limitations of Isosurfaces as well
> anyway? How do you use an isosurface to produce a car or an animal
> model, for example?

exactly!  Figuring out complex functions to model moderatelly complex shapes
with isosurfaces is a pain.  In the end, i think it's really just useful for
random naturally shaped patterns such as rocks or rocky landscapes.  Then
again, people will tell you to use meshes for cars or creatures (already
with displacements)...

I myself would be much happier if blobs were taken more seriously and boxes
were one of the primitives allowed.  It's so much easier to model shapes
with blobs by iteratively adding and subtracting shapes!...

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