Editing Appendix/Ramblings/OculusRiftS (section)

===Model b41c385_DI===

The primary elements of this "DI" scene &#8212; a "direct" Riemann model as viewed from the "inertial" frame of reference &#8212; are (1) the purple ellisoid; (2) a stubby black "cylinder" affixed to the (+X) end of the ellipsoid, as a reference pointer; (3) the grey equatorial (mid-plane) frame; and (4) a clock on the wall with a red "minute" hand and a black "hour" hand.

<ul>
<li><font color="darkgreen">DImod04.dae on 18 April 2020</font>:
<br />I had difficulty importing the ".glb" version of this file into the Oculus Rift S.  I fought with the system for quite a while, thinking that for some reason the Oculus was not recognizing that I had placed a new file in the Lenovo's _Import directory.  Finally, I decided that the problem was with the .glb file itself; that is, even though I was able to "Preview" the .dae file on the Mac, perhaps the Oculus was not importing the file because it was not properly formatted and/or I actually had messed up the underlying COLLADA (.dae) file.  
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I went back to the previous model file &#8212; that is, model DImod03.dae &#8212; and made a new COLLADA file named DImod05.dae.</li>
<li><font color="darkgreen">DImod05.dae on 19 April 2020</font>:
<br />I was able to import the .glb version of this file into the Oculus Rift S.  Displaying only the "northern" half of the Riemann ellipsoid, that is, pieces labeled id="ellippsoid02" and id="ellipsoid01".  The purple ellipsoid did not spin; both hands of the clock are initially pointing in the +X direction, whereas they should be pointing somewhere in the plane that is perpendicular to the X axis; the "minute" hand does not appear to be moving, but the cock-eyed "hour" hand **is** slowly turning.
</li>
<li><font color="darkgreen">DImod06.dae on 19 April 2020</font>:
<br />Deleted most of the COLLADA text that specified animations and specified the visual_scene, leaving only the (northern half of the) purple ellipsoid and its black reference pointer.  In the Mac's Preview app, the ellipsoid could spin properly, but when the model was loaded into the Oculus Rift S, it did not spin.
</li>
<li><font color="darkgreen">DImod07.dae on 19 April 2020</font>:
<br />Deleted more lines of code &#8212; getting rid of the black reference pointer **and** tying spin to only one octant of the ellipsoid, for example &#8212; trimming the animations and visual_scene down to the point where the code closely matches Try06_Zup01.dae.  In the Mac's Preview app, the ellipsoid could spin properly, but when the model was loaded into the Oculus Rift S, it did not spin.
</li>
</ul>