In article <3eac0502@news.povray.org>, Wolfgang Wieser <wwi### [at] gmxde> 
wrote:

> Okay, then please give me your advice: How should I set up the scene 
> correctly? I'll do just that and we'll see if it looks nice. 
> 
> I want to animate a space ship which flies to a planet, along a valley 
> in the topography and back up into space. 

A sphere primitive for the planet. As you get closer, a mesh of the area 
visible from the ship...a few hundred thousand triangles, maybe a 
million. Once you get close to the canyon, switch to a high level of 
detail mesh, the detail will probably require a million or so. Then back 
through a medium LOD mesh (maybe the same as the one on incoming, maybe 
different) and then switch to the sphere again. 2 or 3 meshes, none 
having anything near 100 million triangles. You could set things up so 
you have one bigger mesh with variable amounts of detail, highest in the 
canyon...simpler but less efficient, but nowhere near as bad as your 
idea of using a full-resolution mesh of an entire freaking planet. 
*That* is just wasteful on current systems, even if you have the RAM for 
it.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
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Wolfgang Wieser wrote:
> 
> [...]
> Okay, then please give me your advice: How should I set up the scene
> correctly? I'll do just that and we'll see if it looks nice.
> 
> I want to animate a space ship which flies to a planet, along a valley
> in the topography and back up into space.

I recently showed some samples of high detail rendering of the earth with
variable level of detail.  See:

Subject: rendering the earth (71k+68k)
Date: Tue, 01 Apr 2003 22:57:55 +0200
From: Christoph Hormann <chr### [at] gmxde>
Newsgroups: povray.binaries.images

The data the renders are based on would result in ~3.5 billion triangles
when rendered as a whole with a mesh.  

You can apply the same method (i.e. rendering a planetary body with an
isosurface defined by image maps, using higher resolution data for the
foreground part and blending with the lower resolution basis using
functions) to any other planet.

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 28 Feb. 2003 _____./\/^>_*_<^\/\.______

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Christopher James Huff wrote:

> none having anything near 100 million triangles. You could set things up so
> you have one bigger mesh with variable amounts of detail, highest in the
> canyon...simpler but less efficient, but nowhere near as bad as your
> idea of using a full-resolution mesh of an entire freaking planet.
> *That* is just wasteful on current systems, even if you have the RAM for
> it.

I'm rendering a scene right now that has over 130 million triangles and
the parse time for just the mesh include files is about 8 minutes on my
1 ghz machine. Add in texture computations, radiosity, area lighting,
the trace function and few other things, the total parse time is around
12 min. I would hate to do that for every frame of an animation...!

-- 
Ken Tyler

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In article <3eabfca7@news.povray.org> , Wolfgang Wieser <wwi### [at] gmxde>  
wrote:

> What about 1 byte per triangle?
>
> It only works for planets with 2 byte height info with the height
> info being the height difference to a sphere surface.

Why do you use a mesh if you want a height field???  You can already do what
you suggest easily with POV-Ray 3.5 using an isosurface and an image map
pattern!

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

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Wolfgang Wieser <wwi### [at] gmxde> wrote:
> I was talking about culling as a technique to keep the mesh include file 
> small. Because if you have a 100 million triangle mesh of a planet but 
> only see 5% of them, you can try and do viewport culling -- otherwise 
> the mesh will not fit into memory. 

  There's no way of knowing which parts of the mesh will not be visible
in the final image other than raytracing the image.
  Raytracing is more versatile than scanline-rendering: In scanline rendering
when a triangle is facing away or if it's located outside the viewing port,
you know that it will not be visible. However, raytracing is not that simple.
A triangle can be far behind the camera, yet be visible in the final image.


-- 
#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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Ken wrote:

> I'm rendering a scene right now that has over 130 million triangles and
> the parse time for just the mesh include files is about 8 minutes on my
> 1 ghz machine. 
>
I cannot imagine that. 
I have to wait >4 minutes to get 1 million triangles parsed 
on a 1.4 GHz box. 

Furthermore, you must have more than 4Gb of virtual memory. 

Wolfgang

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> I recently showed some samples of high detail rendering of the earth with
> variable level of detail.  See:
> 
> Subject: rendering the earth (71k+68k)
> Date: Tue, 01 Apr 2003 22:57:55 +0200
> From: Christoph Hormann <chr### [at] gmxde>
> Newsgroups: povray.binaries.images
> 
Looks pretty cool!

Did you "request" the data?
("Files denoted by double asterisks (**) are available upon request. 
Please send an email to...")

> You can apply the same method (i.e. rendering a planetary body with an
> isosurface defined by image maps, 
>
Thanks, the isosurface image map sounds promising. 2 bytes per sample 
is just great. Hope it does not take ages...

> using higher resolution data for the foreground part 
>
okay...

> and blending with the lower resolution basis using
> functions) to any other planet.
> 
"blending using functions"... What do you mean by that?

Wolfgang

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Wolfgang Wieser wrote:
> 
> Ken wrote:
> 
> > I'm rendering a scene right now that has over 130 million triangles and
> > the parse time for just the mesh include files is about 8 minutes on my
> > 1 ghz machine.
> >
> I cannot imagine that.
> I have to wait >4 minutes to get 1 million triangles parsed
> on a 1.4 GHz box.

Guess I should have put a decimal place in there :) 1.30 million.
What's really going to blow you away is that I have 2000 copies
of those 1.3 million triangles in my scene. You do the math....
 
> Furthermore, you must have more than 4Gb of virtual memory.

I have 1 gig of physical memory installed and a seperate partition I use
for the swap file that is 1.5 gigs in size. The current scene is using
a bit under 300 megs.

-- 
Ken Tyler

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Wolfgang Wieser wrote:
> 
> [...]
> 
> Did you "request" the data?
> ("Files denoted by double asterisks (**) are available upon request.
> Please send an email to...")

No, they are available on the ftp server mentioned on that site:

ftp://gloria2-f.gsfc.nasa.gov/pub/stockli/

> > and blending with the lower resolution basis using
> > functions) to any other planet.
> >
> "blending using functions"... What do you mean by that?
> 

Well, you need a function to select whether the low or the high resolution
map is used at a certain position.  To avoid problems with the root finder
you will need to  create a smooth transit between the regions.

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 28 Feb. 2003 _____./\/^>_*_<^\/\.______

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> Guess I should have put a decimal place in there :) 1.30 million.
>
Ah, allright. 

> What's really going to blow you away is that I have 2000 copies
> of those 1.3 million triangles in my scene. You do the math....
>  
The meshes internally use refernece counting. 
There is little overhead copying a mesh because they share the data. 

Wolfgang

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