Dear all,

I'm a new user of POVRAY.

Now I'm gonna use POVRAY for visualizing ground motion on the surface of the
Earth. The computation results give us a 3-D volume of ground motion amplitudes,
and I want to show these amplitudes on topography and subsurface. I found the
figures on the internet and these are exactly what I want:

For 2-D array:
http://www.eri.u-tokyo.ac.jp/furumura/tsunami/Zisin_snap.jpg

For 3-D volume:
http://www.eri.u-tokyo.ac.jp/furumura/scat/3Dsnap.jpg

Now I can draw topography and sea floor, but I have no idea for visualizing the
seismic wave. My question is, which functions should I use for this purpose,
including visualizing 2-D and 3-D datasets?

Thank you.
Best Regards,

M.-C. Hsieh

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MCHsieh <duo### [at] gmailcom> wrote:
> Now I'm gonna use POVRAY for visualizing ground motion on the surface of the
> Earth. The computation results give us a 3-D volume of ground motion amplitudes,
> and I want to show these amplitudes on topography and subsurface. I found the
> figures on the internet and these are exactly what I want:

> For 2-D array:
> http://www.eri.u-tokyo.ac.jp/furumura/tsunami/Zisin_snap.jpg

> For 3-D volume:
> http://www.eri.u-tokyo.ac.jp/furumura/scat/3Dsnap.jpg

> Now I can draw topography and sea floor, but I have no idea for visualizing the
> seismic wave. My question is, which functions should I use for this purpose,
> including visualizing 2-D and 3-D datasets?

  If you have a heightmap, then the easiest way of rendering it is using
the heightfield primitive (which can be instantiated directly with a B/W
image file where each shade of gray represents an altitude). An unmodified
heightfield will be fitted inside a 1x1x1 cube, so you'll have to use the
'scale' transformation to get it to the proper size on each direction.

  Rendering a 3D point could is a much harder problem and does not have
any trivial, unambiguous solution. One possible solution is to create a
DF3 file, which is basically a 3D density file (an NxNxN cube of density
values) which you can then use to instantiate a cube-shaped media effect.
However, getting it to render properly, while not impossible, can be an
arduous task of fine-tuning parameters and color maps.

-- 
                                                          - Warp

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Warp <war### [at] tagpovrayorg> wrote:
> MCHsieh <duo### [at] gmailcom> wrote:
> > Now I'm gonna use POVRAY for visualizing ground motion on the surface of the
> > Earth. The computation results give us a 3-D volume of ground motion amplitudes,
> > and I want to show these amplitudes on topography and subsurface. I found the
> > figures on the internet and these are exactly what I want:
>
> > For 2-D array:
> > http://www.eri.u-tokyo.ac.jp/furumura/tsunami/Zisin_snap.jpg
>
> > For 3-D volume:
> > http://www.eri.u-tokyo.ac.jp/furumura/scat/3Dsnap.jpg
>
> > Now I can draw topography and sea floor, but I have no idea for visualizing the
> > seismic wave. My question is, which functions should I use for this purpose,
> > including visualizing 2-D and 3-D datasets?
>
>   If you have a heightmap, then the easiest way of rendering it is using
> the heightfield primitive (which can be instantiated directly with a B/W
> image file where each shade of gray represents an altitude). An unmodified
> heightfield will be fitted inside a 1x1x1 cube, so you'll have to use the
> 'scale' transformation to get it to the proper size on each direction.
>
>   Rendering a 3D point could is a much harder problem and does not have
> any trivial, unambiguous solution. One possible solution is to create a
> DF3 file, which is basically a 3D density file (an NxNxN cube of density
> values) which you can then use to instantiate a cube-shaped media effect.
> However, getting it to render properly, while not impossible, can be an
> arduous task of fine-tuning parameters and color maps.
>
> --
>                                                           - Warp

Thank you, Warp. These advises are quite useful to me.

For visualizing a 2-D array, I believe the easiest way is by using heightmap.
On the other hand, I also found interesting movies for plotting the seismic
wave:

http://www.youtube.com/watch?v=98R2d66dlgI&feature=related
http://www.youtube.com/watch?v=Bh2Aj-MLpIo

I guess the movie is not made by heightfield.
How can I do that? By using mesh-related functions?

Thanks again.

M.-C.

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