Ok. I'm trying to model the planet earth using a heightmap of it I
downloaded. The heightmap has Mt. Everest as pure white and the oceans as
pure black Will this code make mt everest and ONLY mt. everest touch the
outside of the containig sphere, or will it extend out of the sphere and
make it look like the top was cut off. I don't really understand how far
reaching the function goes but I think I've figured out that it doesn't
scale with the container.

Here is what I have:

union {   isosurface {
    function {(EarthRadius-EarthHeight(x, y, z).grey)}
    max_gradient 8
    threshold 0.9
    contained_by { sphere { 0, EarthRadius } }
    no_shadow
    pigment { EarthImage
    //color White
     }
    finish  { ambient 1 }
 }
 rotate y*90
 }

Thanks,
Corey

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On Mon, 25 Mar 2002 06:55:32 -0500, "Corey Woodworth" <cdw### [at] mpinetnet>
wrote:
> I don't really understand how far
> reaching the function goes but I think I've figured out that it doesn't
> scale with the container.

One advice. Read _carefully_ documentation (all chapters about isosurfaces),
then read http://www.econym.demon.co.uk/isotut/, and then study examples in
/scenes/ folder available in standard distribution. It helps a lot.

ABX

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By the way, you'll probably get a result which renders a lot faster
(and you will save yourself work) if you use the HF_Sphere() macro
in shapes.inc.

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -

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"Warp" <war### [at] tagpovrayorg> wrote in message
news:3c9f2d17@news.povray.org...
>   By the way, you'll probably get a result which renders a lot faster
> (and you will save yourself work) if you use the HF_Sphere() macro
> in shapes.inc.

WOW! Such a plethora of new shapes for me to play with! I had no idea! :)

 I am having more luck with the macro but it takes forever to parse at
decent resolutions. I know I can save it but I'm still testing different
values. Also the isosurface would be alot  more accurate since it is a REAL
sphere and it uses all the pixels from the bump map instead of just the ones
it sampes. Still very cool though!

Thanks,
Corey

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news:e64u9ukc6rl9hd5crbe2k45erk1sfeb1pq@4ax.com...
> On Mon, 25 Mar 2002 06:55:32 -0500, "Corey Woodworth" <cdw### [at] mpinetnet>
> wrote:
> > I don't really understand how far
> > reaching the function goes but I think I've figured out that it doesn't
> > scale with the container.
>
> One advice. Read _carefully_ documentation (all chapters about
isosurfaces),
> then read http://www.econym.demon.co.uk/isotut/, and then study examples
in
> /scenes/ folder available in standard distribution. It helps a lot.

Yeah I've skimmed through both but a some of it is a lil over my head :)

Corey

> ABX

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On Mon, 25 Mar 2002 13:27:48 -0500, "Corey Woodworth" <cdw### [at] mpinetnet>
wrote:
> I know I can save it but I'm still testing different values.

Values of what ? Resoultion of mesh ? Consider that image_map base on image so
it has some highest limit of resolution.

> Also the isosurface would be alot  more accurate

and much slower, and so much memory optimized when copied, and gradient
sensitive (note I'm advocate of functions/isosurfaces)

> since it is a REAL sphere and it uses all the pixels

AFAIK shape showed in your source at begining of this thread isn't spherical
heigh field, only container is sphere

ABX

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news:nuqu9u4rd9arf7qemfed5nkurhoabb7ogl@4ax.com...
> On Mon, 25 Mar 2002 13:27:48 -0500, "Corey Woodworth" <cdw### [at] mpinetnet>
> wrote:
> > I know I can save it but I'm still testing different values.
>
> Values of what ? Resoultion of mesh ? Consider that image_map base on
image so
> it has some highest limit of resolution.

Yes, but my bump map is *very* large. Much larger than I could make the
resolution
of the mesh without running out of memory i think.

> > Also the isosurface would be alot  more accurate
>
> and much slower, and so much memory optimized when copied, and gradient
> sensitive (note I'm advocate of functions/isosurfaces)

Slower to render? Its definetly faster to parse!

> > since it is a REAL sphere and it uses all the pixels
>
> AFAIK shape showed in your source at begining of this thread isn't
spherical
> heigh field, only container is sphere

Yes but its not limited to the resolution of  the mesh. And even if it is
limited to
the resoultion of the height field, that resolution is a lot higher than I
can
(practically) make the mesh. Still I know very little about this and could
be very
wrong. Please correct me if I am :)

Corey

> ABX

Post a reply to this message

On Mon, 25 Mar 2002 14:11:39 -0500, "Corey Woodworth" <cdw### [at] mpinetnet>
wrote:
> Yes, but my bump map is *very* large. Much larger than I could make the resolution
> of the mesh without running out of memory i think.

Do you really think you see all details on 800x600 render ?

> Slower to render? Its definetly faster to parse!

but when you adjust values and start adjusting of enviroment, in case on mesh
you can use include file with fast parsing, in case of isosurface you can't
use include file with fast rendering

> Yes but its not limited to the resolution of  the mesh. And even if it is
> limited to the resoultion of the height field, that resolution is a lot higher than
I
> can (practically) make the mesh.

The question is, do you really need it ? Do you really make posters with
dimensions 8000x6000

> Still I know very little about this and could be very
> wrong. Please correct me if I am :)

You are right abot accuracy. But You are using wrong method for spherical
mapping for so small image dimensions as presented in p.b.i.

ABX

Post a reply to this message

news:sgtu9u87d7i9966rv1gbas3sra9nmisohe@4ax.com...
> On Mon, 25 Mar 2002 14:11:39 -0500, "Corey Woodworth" <cdw### [at] mpinetnet>
> wrote:
> > Yes, but my bump map is *very* large. Much larger than I could make the
resolution
> > of the mesh without running out of memory i think.
>
> Do you really think you see all details on 800x600 render ?

I plan on scaling it up quite a bit when I'm done and then cropping it back
down. to just the important parts.

> > Slower to render? Its definetly faster to parse!
>
> but when you adjust values and start adjusting of enviroment, in case on
mesh
> you can use include file with fast parsing, in case of isosurface you
can't
> use include file with fast rendering


> > Yes but its not limited to the resolution of  the mesh. And even if it
is
> > limited to the resoultion of the height field, that resolution is a lot
higher than I
> > can (practically) make the mesh.
>
> The question is, do you really need it ? Do you really make posters with
> dimensions 8000x6000

Well I'm not using a CRAZY size 10k bump map. I'm using a 2k one. I know
I won't see all the detatails of it, but with a mesh I only see very few
details.
My mesh keeps looking chunky. :) I up the resolution and it looks less
chunky
but still far from what I want it to be.

> > Still I know very little about this and could be very
> > wrong. Please correct me if I am :)
>
> You are right abot accuracy. But You are using wrong method for spherical
> mapping for so small image dimensions as presented in p.b.i.

So you  suggest I just keep upping the resolution of the mesh untill it
doesn't
look like a mesh at my target resoultion?

Corey

> ABX

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May I interfere?  :o)  Well, I don't know how slow the isosurface solution
is, but I would go for a mesh. If you hesitate to do this because you
consider the memory it needs, please remember that even with an isosurface,
your input is an image_map. This also needs a lot of memory. If you save a
mesh, you nolonger need the bump map.

As for mesh resolution, it normally doesn't need to be very high. Meshes can
be smoothed (faked). I'm not sure an isosurface will look better in this
case.

Btw, don't worry about asking questions. :o)

Regards,
Hugo

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