Celestia Forums

Let me first say this. WOW! CONGRATULATIONS! You all have done amazing work. I know this because I lead the development of a quite similar project at the Denver Museum of Nature and Science. Cosmic Atlas (CA), the simulation designed to work with high end planetariums like the Gates at DMNS, is amazingly similar but know where as complete (although the team has created the most realistic, kick ass milky way I have ever seen).

Celestia is a real testament to the power of Open Source development! When I first conceived of CA, this was what I had ultimately envisioned for the software. Many committed folks developing high quality components for the simple joy of doing something cool and adding to the community’s strength.

A quick bit about what we did with CA at the Gates. The dome we projected onto is a 57’ 25 degree, forward seating theater that holds 135. The system projects some 15M pixels onto the surface using 11 1280 x 1024 DLP projectors at 5000 lumens each. The real-time image generator is an SGI Onyx 3800, IR4 11 pipe formally known as Chewbacca. This bad boy IS the largest SGI image generator in the world. CA is processed and displayed at 60hz to the 11 projectors. All this includes a 50,000 watt 16.4 3D sound system and a few other goodies. It is a pretty sweet theater! I would love to someday see Celestia running in there!

Long story short. Ca was developed (and continues to be developed) by a small staff of dedicated artist, programmers and astrophysicist trying to keep up the magic.

Unfortunately, because of politics, economics among many other things I had to leave my position as Chief Technologist at the museum. I am now consulting on a number of similar projects most notably for Lockheed Martin. From the looks of the quality of this amazing software, you will all be hearing from me much, much more.

Now to my question. As a newbie, having only skimmed the surface of this work I have many questions I am certain I will answer through using the software. But I do have one important thing I need to know about; flightpaths.

I see you can make .avi’s on a widoz platform (I proudly am a MAC user and by the way having just attended the annual meeting of the Astronomical Society and seeing mostly Mac powerbooks…) but is there any code written to record and edit a flight path? As a film/dome/IMAX content producer/director this is an absolute! Unless there is an ability to edit precisely a flightpath and move the camera view at will on that flightpath, the software is not much use for producing shows (same can be said for sound but we will tackle that later). This was no trivial task to accomplish in CA with my limited staff, but in the OS world it may be a cake walk.

If such a beast exist, please educate me. If one does not, lets open up a dialogue to figure it out.

I look forward to learning much more!!!

Hell Howard and welcome to Celestia,
it sounds like you are describing Celstia's Cel and Celx scripting features. You can find information about them from Celestia's two scriptmesiter's, Messrs. Don Goyette and Harrry Schmidt. Their sites are
http://www.donandcarla.com/Celestia
http://www.h-schmidt.net/celestia/
respectively. I am sure we will be very happy to have you around, as the number of people who know enough abotu C++, OpenGL and astronomy are pretty scarce as you can imagine. General info can be found in the Celestia user' guide available ont he main Celestia site. Cheers,

Joe

howard wrote:A quick bit about what we did with CA at the Gates. The dome we projected onto is a 57’ 25 degree, forward seating theater that holds 135. The system projects some 15M pixels onto the surface using 11 1280 x 1024 DLP projectors at 5000 lumens each. The real-time image generator is an SGI Onyx 3800, IR4 11 pipe formally known as Chewbacca. This bad boy IS the largest SGI image generator in the world. CA is processed and displayed at 60hz to the 11 projectors. All this includes a 50,000 watt 16.4 3D sound system and a few other goodies. It is a pretty sweet theater! I would love to someday see Celestia running in there!

For God's sake, I would die to see that !

howard wrote:I see you can make .avi’s on a widoz platform (I proudly am a MAC user and by the way having just attended the annual meeting of the Astronomical Society and seeing mostly Mac powerbooks…) but is there any code written to record and edit a flight path? As a film/dome/IMAX content producer/director this is an absolute! Unless there is an ability to edit precisely a flightpath and move the camera view at will on that flightpath, the software is not much use for producing shows (same can be said for sound but we will tackle that later). This was no trivial task to accomplish in CA with my limited staff, but in the OS world it may be a cake walk.

Maybe it's what your looking for :

http://celestiaproject.net/forum/viewtopic.php?t=5097

Howdy Howard, and WELCOME to Celestia!

It sounds like CA is simply AWESOME, especially at the Gates (no relation to Bill) Planetarium in Denver. I lived there for 17 years (70's and 80's), then in Colo Spgs for 10 years (90's), and now on 120 acres outside of Calhan (NE of the Springs). Loved the Laserium show they had there back in my time. Can only imagine how awesome CA must look in there!

Howard wrote:... is there any code written to record and edit a flight path?

Scripting is definately the way to create your own flights. The AVI recorder is quite limited in Windows Celestia, so don't be too envious. I use a screen-video-capture program to record videos of Celestia trips (using WinXP). Looking forward to the day that someone comes up with an Open Source, cross-platform video recorder that can be built into Celestia.

Looks like Psykotik pointed you to one of our newer contributions, AuReality's AutoPilot (very cool). And Joe (alphap1us) pointed out a couple of Celestia scripting sites.

Cel scripting functionality is the basic, built-in version of scripting in Celestia. The newer version, Celx (Lua), is a full programming language add-on library that provides much more control like in normal programs. Cel scripts can be embedded into Celx scripts, so you get the best of both worlds.

However, I am not sure just how complete the Cel and Celx implementations are in the Mac version of Celestia. There is a topic in the Bugs forum for the Mac OS which might contain more detailed info.

For questions on scripting in Celestia, just pop over to the Scripting forum. Over there, take a look at some of the "Tour" topics, posted by Bob Hegwood (http://home.earthlink.net/~bobhegwood/). He's our resident expert tour script writer, and looking at his Cel scripts will give you a good idea how things work in Cel scripting.

Then, take a look at some of the scripts by Harald and Toti, to see how Celx/Lua kicks Celestia scripting up to the next level.

Have fun!

howard wrote:I am now consulting on a number of similar projects most notably for Lockheed Martin. From the looks of the quality of this amazing software, you will all be hearing from me much, much more.

So what are you planning to "consult" in the context of Celestia? What kind of business are you thinking of?

Bye Fridger

howard wrote:15M pixels [...], 11 1280 x 1024 DLP projectors [...], SGI Onyx 3800, [...], 50,000 watt 16.4 3D sound system

Now I know what I will answer the next time someone asks for what kind of system to buy 80

I see you can make .avi’s on a widoz platform (I proudly am a MAC user and by the way having just attended the annual meeting of the Astronomical Society and seeing mostly Mac powerbooks…) but is there any code written to record and edit a flight path? As a film/dome/IMAX content producer/director this is an absolute! Unless there is an ability to edit precisely a flightpath and move the camera view at will on that flightpath, the software is not much use for producing shows

As Don already wrote you can use scripting - for precise control, you probably should use the CELX-scripting facility in Celestia. It may also be possible to create an invisible object with a predefined path (a xyz-file), and lock the observer on that object.

However the main problem will be to create the flightpath - currently it's not possible to save any data, so you can't simply record a path interactively. But even if you could, you probably would have to edit that information, which I think would be a pain.

Maybe a programmed tour would fit your needs, have a look at the various "Tours" in the scripting forum. If you really need to record data, there is currently one way out if you can compile Celestia yourself (don't know if this is problematic on a Mac), because then you only need to change one line in the sources to allow writing.

As far as I know video recording is not available on a Mac. CELX-scripts allow to capture screenshots, which could then be combined into a video - right now this is a bit tricky (the timing is problematic when using goto-commands), but this can be made to work, assuming you have enough diskspace.

Harald

Thanks for the warm welcome all!

Generally. The Gates is a superb facility and really worth seeing. Unfortunatly it is not without its bugs. Issues with projector alignments and high maintanance of the Onyx made/makes the system quite difficult to manage/run. That being said, the nights I spent sitting in the center of the dome, mouse in hand surfing the rings of Saturn or skimming the surface of Mars were truly spectacular and memorable. If anyone wants to know more, the good, bad and ugly, let me know.

BTW, it is Charlie Gates, of Gates Rubber, not Bill.

Re: question on consulting I would not think of doing anything commercial for Celestia. Can't, won't oh no, no, no...

What is in the works is a Educational/Public outreach program in support of the Moon/Mars Initiative. All of the "giants" in the space industry realize that the dream is quite realistic in spite of it being an election year. Monies are already being shifted within NASA to support the program and there is an optimistic perspective by many (not all) in the industry. What they realize is key is two bits: Continued Congressional support and more importantly grassroots public support.

This is where I fit in.

My job is to meld the best of the science, commerce and museum world to create Ed/Public outreach (E/PO) programs to support this and the many other very important missions out there. I found myself in the enviable position of being in a key place to support key programs with the help of some real money and desire on the part of these big aerospace companies. The corporate mind, while good at marketing, can’t do the kind of outreach a Museum professional understands.

I had originally hoped the Denver Museum would want to play in this very rich/fertile soil but apparently they do not. Politics, egos, economics and staff layoffs (including me) will be a real stumbling block to getting Cosmic Atlas in place as the tool for content dev for this important outreach work.

Then I find Celestia! I can’t say how impressed I am with the work you all have done. Since DMNS doesn’t want to play (and even if they did I would want to use Celestia regardless) it seems as if this software can more than fill the content creation hole I had hoped CA would fill. Celestia can and should be what gets used to produce the E/PO content for these programs.

Now for the practical.

Having worked this before I have a pretty good idea of what I need technically to produce “top shelf” content. Even though I have lead the dev of CA and the Gates, I am not a programmer or engineer. What I am is a geeky, technical artist who has spent my carrier bringing together science and art in a way that is engaging, compelling and meaningful to the visitor/user (I have numerous awards including many “Telly’s” and several Grammy’s for producing and directing). I know all to well that this kind of effort is successful only with a team. I am not a programmer so I can’t hack the code myself. I need the expert help of folks like you so that together we can build something special.

So I will need you all’s kind help and sage advice should this all begin to congeal.

The flightpaths. I want the ability to playback in real-time not as a movie. Making movies will be a part of the final products but what I envision is real-time playback. That way all that gets moved from place to place is the small, in file size, flightpath, not a large movie. This is key as a teaching tool. I have not seen autopilot because I only have a Mac, so I can not say if it will be useful or has the features I will need. As a filmmaker, I must have the ability to “fly” at will, and have the path I have gone down recorded for the sake of editing. As I am flying I also need the ability to pan and/or truck the camera. The resulting product of the “flying exercise needs to be a path, in the form of some sort of Bezier or other editable curve, with key frames marked as required, associated with some sort of timecode, and it must have the ability to adjust the camera angles. I will then need to be able to seamlessly splice flightpaths together. All of this needs to of course be visible.

So I think I am talking about something quite different and more complex than using scripts. I’ve tried that and it can be frustrating as a content developer, especially if you lack programming knowledge as I do. Storytelling, the core of filmmaking, demands the ability to precisely manipulate the audience by where you go and what you see. You can only do this with precise editing tool like I described.

With CA I had always imagined using a PS2 controller for this task. One thumb button (forgive me if I have the terms wrong, I am not a gamer) would control the camera, the other control the “spaceship” and the other buttons would be used to and markers, keyframes, didactic information (camera angles etc.) and the likes. Now if someone can help me get all that we’re going to be laughing!

I can’t promise anything but there may be some opportunities to help the community, individuals and of course the software should this all work. I’m throwing this out there to see what happens. At the very least my clients will be able to provide things like real-time telemetry to attach to models, the latest concepts, technical and content support and the likes. I would hope this is a way for this community to tap into something as of yet unavaliable to you. We will see what I can pull off.

Sorry for the manifesto. I’ll try my best to be short, but there is a lot to say.

I am just now getting into multimedia design where I work...and have been dabbling in it as a hobby for a few years...Most of what you require should be possible in Celestia using Lua....

I for one have been most interested in producing some of the aspects you mention more in the areas of Graphic Design..Anything that has to do with movie production Im highly modivated in! I have some future projects on the drawing board that could well be used to produce a movie or two in the future...The problem is finding the time

For the movie aspect you mentioned, using a Mac has its advantages...I am unaware of 3d modeling software on the Mac but I personally favor 3d studio max only because I have been using it for quite a long time...Maya 3d is also quite excellent but unfortunately they are both pricey for an open source project...

The major drawback vs Celestia, 3d studio has is the time consuming task of putting it all together...As it would be for any 3d modeling program that uses animation...Celestia comes prebuilt to handle all the behind the scenes construction of the meshes and animation, and relies on the users scripting skills to produce the presentations he or she favors...The only other tasks would be Nebula and planets...Meshes have to be constructed for nebulas to your liking and textures for any planets not exclusive to our Solar System.

There is enough documentation floating around to get you underway coding Celestia...I personally find it simple where scripting solar systems comes into play, but a tad more difficult when using celx/lua...This requires more programming skills than most people have.

Howard, welcome to Celestia. Your obvious enthusiasm is of course, shared by us all. Your talents are most welcome.

I am using Celestia extensively in education. I am a high school Astronomy teacher and have written a whole series of "journeys" through the Celestia universe, designed to take an audience to various places, while the written text explains in detail what they are seeing. Although these activities use a lot of hyperlink jumps to take readers from one spot in space to another, they also employ the Celestia spaceship to travel locally, where practical. In fact, a few months ago, I received word from two planetarium directors in Spain and Peru that they were using one of my Celestia Activities as a script for their planetarium shows. Please feel free to drop by my website and download the "Letter to Users and Educators", which explains all of the Activities currently available elsewhere on the same site. The www link to my site is below (under this post).

In reading your first post, my eye caught your description of the kick-ass quality of the Milky Way created by Cosmic Atlas. One of the things the Celestia community has been waiting a long time for, is an improvement in the quality of nebula and galaxies. If you surf the forum, you'll find lots of references to it. All of the current nebula add-ons you will find for Celestia are good but essentially "flat", and the galaxies which the program draws are basically dim blobs. From what I understand, the coding, calculations and/or cpu requirements needed to actively draw swirling nebula, 3-dimensional colored gas clouds that you could actually fly through and rotating galaxies, are beyond the current abilities of Celestia. If you have any ideas for incorporating an improvement in nebula/galaxy drawing in Celestia, we would all be grateful and enthused.

Anyway, welcome to the community and I look forward to seeing you as a frequent visitor/contributor.

Regards,

Frank

don wrote:For questions on scripting in Celestia, just pop over to the Scripting forum.
Over there, take a look at some of the "Tour" topics, posted by Bob Hegwood
(http://home.earthlink.net/~bobhegwood/). He's our resident expert
tour script writer, and looking at his Cel scripts will give you a good idea how things
work in Cel scripting.

Man, oh man...

If you think I'm an "expert tour script" writer, then I'm afraid that the
Celestial Community is in deep trouble!

Take care, Bob

Bob,

the Celestia Community is not in deep (tour-script)trouble because of YOU!
Do not always place your light under the pot!

@ howard: Also a warm welcome from me.

Adirondack

Bob,

the Celestia Community is not in deep (tour-script)trouble because of YOU!
Do not always place your light under the pot!

@ howard: Also a warm welcome from me.

Adirondack

Hi Frank (and all)

I have already had a play with your educational scripts and the are superb. I can already see many uses for such beasts, especially running on a small 1.5 meter “personal dome” such as what Elumins makes.

That being said, trying to direct/produce a dome show or something for say IMAX, would be impossible working with scripts. The precise control of the camera placement, FOV, and timing is critical to be able to produce high production value content. No slams here, it is just a fact. You all have done superb and I want to help move it to the next level, or more properly, branch it to a new space, movie making.

As for the Milkyway. At DMNS we originally had planed on creating a sim of a spiral arm galaxy with some code the populated the model with supernove, distributed by type size etc. based on algorithms taken from current knowledge. The sim then ran forward and “spawned” new stars based on these complex algorithms (this is stuff way beyond me. We had several astrophysicist working it) to generate star populations, distributions and dust lanes. From that, the model was sub divided into 10ly cubes and textures were generated for all sides of each cube from a view point at the center of each cube. “Local” stars were added to each cube and these would overlap into any adjacent cube. As you flew, the cubes were loaded as VT’s (called clipmaps in SGI lingo).

Now since I left the museum, the team has figured out a much more efficient way of doing this work. I have seen the results and they are absolutely stunning. Celestia is better than CA in many, many areas but this on bit DMNS wins hands down. The result is so realistic (ya, cause we have all flown there….) and knowing that it is based on real science, it blows one away. I am hoping something can be worked out to use it but I am not holding my breath. The Museum is stuck at the Intellectual Property crossroads and at this time is unwilling to open source things.

As for Nebula, there are several approaches. Take an image from Hubble and create a mesh using a modeling package (back side detail will need to be inferred. Some of the inference can be based on measurements we currently have) and the Hubble image slapped on as a texture. This is what the Hayden did with the Orion Nebula. Make believe ones can be created with fractal algorithms. The DMNS staff had some quite convincing results that even fooled a PhD with this one!

From what I can tell Celestia could render a similar galaxy. It will require some work but I think it can be done. I am hopeful that the project I am working on will be able to move some of these bits well forward.

I would like to know if the application in the domes in Spain and Peru took full advantage of the dome or was it projected to one screen. Another key need from my perspective is “dome enabling” Celestia. We will need a 360 x 160/180 degree FOV configuration for this to work. Any one worked on this at all?

howard wrote:That being said, trying to direct/produce a dome show or something for say IMAX, would be impossible working with scripts. The precise control of the camera placement, FOV, and timing is critical to be able to produce high production value content.

If I understand you correctly you want lot's of "keyframes" (which would consist of a time, a position and an orientation), with movement smoothly interpolated between those frames. There are two problems here: creating the tour, and playback of the tour.

CELX-scripts can change camera placement, FOV for every frame rendered by Celestia. Normally you don't want this, because it's much easier to say "go from here to Mars in 5s" than to create a list with every position in between. There is one problem with timing, because the duration of one frame is non-deterministic. Limiting Celestia to e.g. 25fps would possibly make it's realtime behaviour much more deterministic (as long as the system could provide >25fps), or you would have to record the tour as a movie with perfect timing.

The real problem lies in creating the tours. How do you create hundreds or thousands of "keyframes"? How could you edit them? Scripts could help here, but I am not sure if they can provide what you want - which leads to the question: what exactly do you want/imagine?

Harald

Howard,

I have to admit that I like your ideas!

Unfortunately Celestia currently has limitations that'll get in the way of what you want to do. There are some not-quite-satisfactory workarounds, but I think some work will be needed on the source code to provide the features that you need.

1) Celestia's stars can only be drawn within ~16KLY of the solar system.
2) one or two million stars make Celestia rather slow.

A 3D model can be created that consists of millions of glowing points located at arbitrary distances in space (although I haven't tried more than ~300K yet). They are handled much more efficiently than individual stars, but they do not (yet?) have 1/r^2 attenuation applied to the portions of the model that are far away from the viewpoint.

I have to admit that I'd be very interested in getting a copy of the galaxy/star generation algorithm!

3) Celestia is currently limited to a viewport that's 120 degrees across. When forced to draw larger viewing angles, the display does strange things.


Currently, the primary limitation in adding graphic features is that there's only one person involved in coding who understands all the necessary interactions. And Chris is quite busy with other priorities at the moment.