Good point, if I use expressions to correct the rotation problems re the environment map and any SI world null rotation parameters... They have to be connected in a strange manner, at least as of 2014. Don't imagine they've fixed that...
Thanks, Nancy On Jun 24, 2014, at 1:22 PM, Matt Lind <ml...@carbinestudios.com> wrote: > If you're just going to create a sphere with specks on it, why don't you use > an environment shader? That does the same work without having to create a > sphere, deal with camera rigs, or mess up your ray depth computations in the > render. > > > Matt > > > > > > > > -----Original Message----- > From: softimage-boun...@listproc.autodesk.com > [mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Ponthieux, > Joseph G. (LARC-E1A)[LITES] > Sent: Tuesday, June 24, 2014 6:25 AM > To: softimage@listproc.autodesk.com > Subject: RE: Ideas for star fields? > > Oh and one other thing. You may find that constraining the star field sphere > position directly to your camera and forcing the sphere orientation to remain > in sync with the scene will produce the best results. Render the stars out as > a pass and comp everything over them as the base image. By doing this the > "stars" will always maintain an exact distance from the camera and since > stars are such an incredible distance from us in space the illusion is > remarkably similar. It will also make the appearance of the stars much more > predictable as you can set them for what you want and you no longer have to > worry about that appearance changing other than camera orientation. > > -- > Joey Ponthieux > LaRC Information Technology Enhanced Services (LITES) Mymic Technical > Services NASA Langley Research Center > __________________________________________________ > Opinions stated here-in are strictly those of the author and do not represent > the opinions of NASA or any other party. > > >> -----Original Message----- >> From: softimage-boun...@listproc.autodesk.com [mailto:softimage- >> boun...@listproc.autodesk.com] On Behalf Of Ponthieux, Joseph G. (LARC- >> E1A)[LITES] >> Sent: Tuesday, June 24, 2014 9:13 AM >> To: softimage@listproc.autodesk.com >> Subject: RE: Ideas for star fields? >> >> The problem is that you are using Hubble images. Hubble images are high res >> and beautiful but often are only representative of a single focal point in >> space. What you want is a "star map" that is a cylindrical projection suited >> for >> your sphere. You will find the maps you need at this link. In particular the >> high res Tycho maps are probably what you want. >> >> http://svs.gsfc.nasa.gov/vis/a000000/a003500/a003572/ >> >> When you map these onto your sphere you will notice that the center of >> your sphere of the focal point of a "disc" or "ring" of stars. You'll see >> the >> "ring" form on the inner side of the sphere. There were three maps >> historically, Tycho, Hipparcos, and Yale. The following links contain them >> but >> these do not look like the highest res versions. >> >> http://www.nasa.gov/multimedia/3d_resources/assets/tycho8.html >> >> http://www.nasa.gov/multimedia/3d_resources/assets/hipp8.html >> >> http://www.nasa.gov/multimedia/3d_resources/assets/yale8.html >> >> >> Each was created at different resolutions and star counts. One is synthetic I >> think, and that I believe is the Yale map based upon the Tycho catalog. The >> map is of higher contrast and may lack a lot of the intermediate or >> diminished >> stars so it may be useful in some circumstances. You'll have to figure out >> what the basic appearance is that you are looking for and a combination of >> the maps may be what you want. As you probably have already discovered, >> you won't be able to let your camera get too close to the texture surface as >> the stars will become abnormally large and the illusion will be lost. Its >> best if >> you scale the sphere as large as you can and keep the surface as far from the >> camera as possible to reach the effect you want. >> >> If you want a moving starfield, the best way to achieve that is generate a >> massive field of small triangles set to constant white. The distance apart, >> size, >> and randomness will have to be worked out. You can do this as particles as >> well, but if the particles are set to pixel height you'll lose the sense of >> perspective and distance as you fly through them. >> >> -- >> Joey Ponthieux >> LaRC Information Technology Enhanced Services (LITES) >> Mymic Technical Services >> NASA Langley Research Center >> __________________________________________________ >> Opinions stated here-in are strictly those of the author and do not >> represent the opinions of NASA or any other party. >> >>> -----Original Message----- >>> From: softimage-boun...@listproc.autodesk.com [mailto:softimage- >>> boun...@listproc.autodesk.com] On Behalf Of Nancy Jacobs >>> Sent: Monday, June 23, 2014 5:43 PM >>> To: Softimage Listserve >>> Subject: Ideas for star fields? >>> >>> Hello, >>> >>> I'm needing a star field kind of background for a scene, and looking for >> ideas >>> to create it. I have been using Hubble images wrapped around a sphere, >>> around the scene, but I'm finding it doesn't read well, even with very high- >>> res Hubble images. >>> >>> So, I'm wondering about other ways to create star fields. Has to be 360 >>> degrees, seamlessly -- and I don't have the capability to deal with that in >>> a >>> compositing situation. >>> >>> So....any ideas? >>> >>> Thanks, >>> Nancy > > >
