Help making flat billboards on the plane of the Galactic
Posted: 12.04.2010, 20:00
Hey Guys,
I'm having some trouble wrapping my head around some perimeters and I was hoping some of you smart fellows might be able to help me out. What I'd like to do is create some star chart images to lay flat on the plane of the galactic. I've been having fun playing with some of Selden's billboard meshes but the goal of those are to always position the billboard facing toward earth. My project is based on an overhead view looking face down on the plane of the galactic.
The problems I'm having are in figuring out how to define the borders of my images, orient them properly flat on the plane and how to position them precisely in space where I'd like them to be. I've had some success in making simple cmods, connect the dots mostly. I'm sure I've gone about it in a totally wacky way so far but it's the only thing I've yet to have success with not having significant programming knowledge or experience.
What I've been doing is a bit of a convoluted process, first I start with an XYZ coordinate based on my top down view of the galactic plane centered on SOL and using lightyears as units, with that I can easily get the L2 and B2 galactic coordinates and distance. Then using Nasa's HEASARC Coordinate converter I can convert the galactic coordinates to J200 Ecliptic to give me the RA and DEC which I apply the same distance to create STCs and such. Only once I've found the RA DEC and distance by these methods can I then convert that info into the cmod coordinates I need which I then use to create cmod models by hand. Convoluted yeah but I just don't know any other way yet!
I've created and Excel spreadsheet to facilitate all these equations and conversions. With the exception of a brief jaunt to the Nasa website it's pretty pared down and it allows me to make frames for my future map overlays of the precise dimensions and locations I want them to be in. Like this:
Selden's Billboard mesh seems Ideal but I don't really understand the info in his cmods or how to modify them to my own needs and overlay my desired images. But I'm ready to take the next step in understanding if anyone can help to illuminate me.
As always much appreciation to anyone who can help!
I'm having some trouble wrapping my head around some perimeters and I was hoping some of you smart fellows might be able to help me out. What I'd like to do is create some star chart images to lay flat on the plane of the galactic. I've been having fun playing with some of Selden's billboard meshes but the goal of those are to always position the billboard facing toward earth. My project is based on an overhead view looking face down on the plane of the galactic.
The problems I'm having are in figuring out how to define the borders of my images, orient them properly flat on the plane and how to position them precisely in space where I'd like them to be. I've had some success in making simple cmods, connect the dots mostly. I'm sure I've gone about it in a totally wacky way so far but it's the only thing I've yet to have success with not having significant programming knowledge or experience.
What I've been doing is a bit of a convoluted process, first I start with an XYZ coordinate based on my top down view of the galactic plane centered on SOL and using lightyears as units, with that I can easily get the L2 and B2 galactic coordinates and distance. Then using Nasa's HEASARC Coordinate converter I can convert the galactic coordinates to J200 Ecliptic to give me the RA and DEC which I apply the same distance to create STCs and such. Only once I've found the RA DEC and distance by these methods can I then convert that info into the cmod coordinates I need which I then use to create cmod models by hand. Convoluted yeah but I just don't know any other way yet!
I've created and Excel spreadsheet to facilitate all these equations and conversions. With the exception of a brief jaunt to the Nasa website it's pretty pared down and it allows me to make frames for my future map overlays of the precise dimensions and locations I want them to be in. Like this:
Selden's Billboard mesh seems Ideal but I don't really understand the info in his cmods or how to modify them to my own needs and overlay my desired images. But I'm ready to take the next step in understanding if anyone can help to illuminate me.
As always much appreciation to anyone who can help!