Making a movie

Let's take the 2nd movie below as an example of how the movies and the related data products come about. Note, that I will explain later what these files show.

1. The IDL procedure mf_02 calls script1 101 times, each time changing one or more parameters; in this case a/M is changed from 0.00 to 1.00. It writes 101 Inventor files, called frame000.iv, ..., frame100.iv.
2. Explorer is used to make 101 RGB images from the 101 Inventor 3D scenes. In turn, the Inventor files are read using the module ReadGeom, rendered using the module Render, and written as an RGB image using the module WriteImg. A For module and two AnimFile modules are used to automate the process for all 101 frames. Before the run is started, the user interactively positiones the first (or last) 3D scene in Render, finding a nice view / camera setting. This is used for all 101 files, then. The Render window size is chosen to be 448 pixels by 448 pixels, i.e. multiple of 16. The technical details are described further in an appendix.
3. The IDL procedure mf_02_an is used to annotate the images - in this case, the text ``a/M=0.00'', ..., ``a/M=1.00'' is overlayed in the lower right corner of the images. It calls annotation_image 101 times, and every time the temporary annotation image is added to the ``real'' image (which Explorer produced) using the Silicon Graphics UNIX command add. add has the side effect of transforming the uncompressed RGB files that Explorer produced to RLE compressed RGB files, reducing the file size by a factor of 4, from 600 kbyte ( byte) to 110-160 kbyte.
4. The Silicon Graphics UNIX command dmconvert is used to make an Animation coded QuickTime movie, movie02.qt, and an MPEG movie, movie02.mpeg. This is done by this C-shell script.
5. The Silicon Graphics UNIX command togif is used to make 101 GIF images, frame000.gif, ..., frame100.gif from the RGB images. The size of the GIF files is only 23 kbyte. The public domain UNIX program GIFMerge is used to make an animated GIF, movie02_anim.gif. This is done by this C-shell script.
6. The UNIX program xv is used to make a PostScript file, frame000.ps from the first RGB file. The black background color is changed to white, and the yellow annotation text color changed to black, well suited for printing.
7. All the RGB files are deleted.
8. The Silicon Graphics UNIX command ivToVRML (see here) is used to make 101 VRML files, frame000.wrl, ..., frame100.wrl from the 101 Inventor files. This is done by this C-shell script.
9. The Inventor and VRML files are compressed using gzip, reducing the file size by a factor of 5.
10. All the visualization files in the directory in question take up about 12 Mbyte of disk space.