Yes, I was able figure out how to plot a half-ellipsoid: http://jsoftware.com/pipermail/programming/2015-March/041280.html
Then I wanted to map a photo of a face on the ellipsoid. I was eventually able to do this in Mathematica, but I was never able to do the mapping in J. Skip Skip Cave Cave Consulting LLC On Thu, Mar 19, 2015 at 10:06 AM, Raul Miller <[email protected]> wrote: > The original thread was about rendering an ellipsoid using plot: > > http://jsoftware.com/pipermail/programming/2015-March/041251.html > > I couldn't figure out how to get plot to render one, so I came up with > this: > > https://www.shadertoy.com/view/XtlGDX > > Skip managed to work out some J plot examples: > > http://bit.ly/1Be186L > > http://jsoftware.com/pipermail/programming/2015-March/041280.html > > And then the thread got off on the issue of texture mapping and the > fact that someone needs to bring the opengl labs forward (since the J6 > labs are based on an archaic implementation of OpenGL and the laziness > inherent in human industry suggests that we should get things working > now, while we can, before more things break). > > Anyways, it's good to hear from you. > > Thanks, > > -- > Raul > > > On Thu, Mar 19, 2015 at 8:17 AM, Cliff Reiter <[email protected]> > wrote: > > I forget the original thread. Are you trying to plot ellipsoids (egg > > shapes)? > > You can modify the scale factor in spherical coordinates for each axes: > > x = rx (sin t) cos f > > y= ry (sin t) sin f > > z = rz cos t > > where 0<: t<2p1, 0<:f<:1p1 and rx, ry, rz give the axis lengths parallel > to > > x y and z axes. > > Do you need to rotate this in space? > > > > On 3/19/2015 1:44 AM, Raul Miller wrote: > >> > >> > >> > https://johncarlosbaez.wordpress.com/2015/03/17/planets_in_the_4th_dimension/ > >> looks like a plausible approach for finding parametric descriptions of > >> ellipses. > >> > >> I've not tried it, though. > >> > >> Thanks, > >> > > > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
