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Behind the scenes of the SDSS Movie

DR3, April something 2005

480 x 272 movies (lefteye) 300Mb 95Mb made with snap, jump

Looks okay on Windows. Heaven help the rest of the universe.

These were made with the Partiview files in, using this cf file.

Part 1

From the sun to the local galaxies, just before the start of the Sloan Galaxies. 335 frames. No rotations. . Two possible versions, with (36 Mb) and without (24 Mb) fading. The difference in file sizes is because the MPEGs were made at 40 and 30 kbits/sec respectively.

The unfaded version was made with these, jump and snap files.

The faded version was made with the same wf file, but with these jump and snap files.

Note: Once this is completed, you need to make sure quasars are off (g7 off) and the near clipping place is 10000 (clip 1e4).

Righteye versions! faded, unfaded.

Part 2

The Sloan Galaxies. 1832 frames. 10kbits/sec. No quasars. Straight zoom out, until the last Sloan Galaxies. part2_may25_left_1kbs.mpeg is 32Mb, and is at 1kb/s.

These were made with the following wf, jump and snap files.

Righteye MPEG

Part 2a

An alternative version of this with 1790 frames at 1kb/s: This starts at the same place, but doesnt zoom out as much. Instead it has a rotation. part2a_left.mpeg (39Mb). It is composed of the first 1450 frames of the previous movie, followed by the rotation in a separate mpeg (if you need it, it's called sdssrotate.mpeg).

Here are the wf, jump and snap files used to make it.

Righteye MPEG

Part 3

This follows 2a, not 2. Nothing follows 2. Yes yes I know, it's a horrible naming convention.

We now rotate the other way (180 frames).

The requisite wf, jump and snap files.

(Note: This is the second version of the rotation, changed after 8pm on May 25.)

Righteye MPEG

Part 4

Zooming out straight now, slowly brightening up the quasars and CMB.

The CF file was modified so that quasars and the CMB were turned on (it's not necessary to set alpha=0 explicitly, that's taken care of in the snap file).

MPEG, 16Mb. At 5 kb/s. (For some reason, this is the same size as the 1 kb/s version. Weird.)

Righteye MPEG

Here are some notes on how this was made, for future reference. Here are the wf, jump and snap files.

partiview > wherefile &
This is followed by manually finding a good flythrough, in this case just zooming straight back till the CMB globe fitted in the screen.
perl wherefile
Delete a couple of lines at the start of they're the product of early unused jump statements in the .cf file
This produces part4_jump
perl part4_jump part4g1alpha_jump max\(0,min\(0.35,0.35\*\(DIST-1.1e9\)/3.6e9\)\) g1 alpha DISTDEPVALUE
This increases the value of alpha for group g1 (CMB) from 0 at the start of the path to 0.35 (when the distance from the origin is about 1.1e9) somewhere in it (when the distance from the origin is 1.1e9+3.6e9 = 4.7e9). The increase is linearly with distance, and thus exponential with time, but that's ok. Note that you have to put backslashes before parentheses and asterisks in the arguments to Also, these parameters may not be exactly the ones I used, but they're close enough. My computer crashed in between writing this documentation and producing the original movie.
perl part4g1alpha_jump part4g1alphag7alpha_jump max\(0,min\(0.975,0.975\*\(DIST-1.1e9\)/1.2e9\)\) g7 alpha DISTDEPVALUE
This increases the value of alpha for group g7 (Quasars) from 0 at the start of the path to 0.975 (when the distance from the origin is about 1.1e9) somewhere in it (when the distance from the origin is 1.1e9+1.2e9 = 2.3e9).
perl part4g1alphag7alpha_jump
This produces part4g1alphag7alpha_snap, which is exactly the same as the _jump file, but also takes snapshots. jump files are useful for testing that the parameters are right before taking pictures, by going to partiview and saying "async blah_jump", once the blah_jump file is chmodded +x.
chmod +x part4g1alphag7alpha_snap
partiview &
Close command window in PArtiview
(in Partiview) async ./part4g1alphag7alpha_snap
This produces a series of .sgi files
perl snap.*.sgi
This converts the .sgi files to .ppm files
convert snap.000.sgi snap.000.ppm
For some reason, the first file in the argument list to doesnt get converted. I should fix that, but I prefer bandaid.
mpeg2encode mpeg2encode.par part4left.mpeg

Part 5

The CMB spins 360 degrees. Approximately... you may have to use the first 362 frames of the 365 used here. Or the alternative mpeg also provided in a couple of paragraphs.

part5left_8kbs.mpeg (13Mb). A smaller version at 4kbs (7Mb) was also made - dont use it unless you really have to.

This alternative mpeg has 362 frames, so the transition may be better when looping. (Transitions differ with mpeg players.)

wf, jump and snap files.

Righteye MPEG : unfortunately, this has only 361 frames. Not sure what happened. Can remake, would rather not.

Part 0

Zoom into New Mexico from earth: Partiview used with and these wf, jump, snap files to create
Left MPEGS: 10kb/s (17Mb).

Right version can be created by replacing "stereo -0.005 left" with "stereo -0.005 right" command in .cf file and running NM_snap again. Problem: hiccup during flyin... noticeable?

Dinoj Surendran was very tired when he documented this.


Regenerated Parts 2,3,4,5 (4+5 combined) using DR3 data.

CF file

Snap files: 2 (old 2a path) 3, 45.

mpeg2encode.par. You'll need to modify the parameters for number of frames and use snap.%04d or snap.%03d for the name of the source files. The bit rate used here was 28 800 000 kbps. (I think it's kbps.), and half that for part 2.

MPEGs (left eye) : 2 , 3 (20Mb), 4+5 (128Mb),