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
