Active Galactic Cores

[buggs_moran]

Well, after being sufficiently wowed by Cham's great black holes, and having gone to a Chandra Workshop last summer, I thought I would try my hand at making my own add-on (hopefully to store at the center of some of Fridger's (soon to be) most excellent rendered galaxies (are any active?))

My inspiration comes from the Chandra site...

Forgive me if the models are too crude, the graphics have seams, yada, yada. It is a work in progress. Overlapping models stink. It is nice in motion, but needs work...

[Cham]

OOOH YEAAAH !

Great stuff to come ! I like it !

Beware of the disk's edges. The textures should become 100% transparent at the edges, or else, you'll see sharp unatural edges, like on your second picture.

I especially like the third and last pictures.

I can't wait to install this on my system

[buggs_moran]

Beware of the disk's edges. The textures should become 100% transparent at the edges, or else, you'll see sharp unatural edges, like on your second picture.

Thanks for the vote of confidence Cham. I am not very graphically adept with transparencies. Most of the things I have done in the past are limited to just a static picture.

Anim8tor cannot use pngs, Celestia cannot use gifs. How do I achieve basic black or even a transitioning transparency while maintaining the gas structure of the outer disk on a 3ds exported from anim8or? If I crank the transparency of the disk up too high to lose the black, I lose red too...

[buggs_moran]

Oh yeah, plus I think I read somewhere that stars (my barycenter) wont show up outside of a certain distance in Celestia. Will that kill this idea totally?

[ElChristou]

Great work... I think you both should work together to create a new "generation" of BH

Bye

[Cham]

buggs_moran,

I would be very surprised if your 3D modeler cannot map PNG. If so, then you may have a problem. Maybe you should change the modeler.

The PNG files should be done in Photoshop or any other equivalent graphical software. I remove the black with the background eraser in Photoshop. Here's the setting I'm using : "Background eraser" with Limits set to "Discontiguous", Tolerence set to 60% and "Protect Foreground Color" set to ON. You can play a bit with the Tolerence for some variations.

According to the pictures above, you have a VERY good model to start on. You should continue with it, and experiment a lot. Geez, I have a lot to say here, and English isn't my first language.

I started my first black hole because I was disatisfied with the only one available for Celestia (this one : http://www.celestiamotherlode.net/catal ... don_id=183). It was too simplistic, too crude for my tatste. I'm still not totally satisfied with my own creations. I made several experimentations with transparencies and 3ds meshes to learn Celestia's limitations. You'll discover it may be very frustrating trying to work around all the limitations Celestia is imposing on us for nebulae rendering, blurry masses of gas, volumetric effects, etc. But it's fun as hell too, and that's important !

I discovered that, for objects with transparencies, we are limited to planes and almost planar bulky disks. If the bulge is too thick, you'll see its hard edge INSIDE while rotating around. Take a torus with some semi-transparent texture mapped on its surface, for example. You'll see the torus hole through the exterior side while rotating around. This looks totally unatural. We currently don't have any volumetric effect in Celestia and that's the main problem. We have to work around that limitation.

And there's a bug entering the scene : if you have several transparent layers, Celestia doesn't depth sort them all correctly. Look at the jets on any of my black holes. The one which is BEHIND the accretion disk looks exactly the same as the one which is in front. This is a bug related to transparent objects, and currently there's nothing we can do about it (unless there's something I missed ?).


Autocrittic : my black holes are using too much transparent parts on the central accretion disk. I believe that matter is so densely packed close to the hole that the accretion disk should be totally opaque near the center. Your second picture is much closer to what should be the real thing. But real black holes may be VERY complicated, actually. Some are very "quiet", without lots of falling matter (so a transparent disks ?) and some other are hungry pigs eating like an ogre a thick disk of dense matter.


About the stars, you said :

>>Oh yeah, plus I think I read somewhere that stars (my barycenter) wont show up outside of a certain distance in Celestia. Will that kill this idea totally?<<

Yes, there's a limitation. Celestia cannot show a star defined above the 16000 LY barrier around our sun. So you wont be able to place anything (except DSC) in another galaxy. That's why I selected the Tucanae globular cluster to hold most of my black holes. Most astronomers believe there are many BH in there anyway, because it's a dense pack of stars. Forget the idea to put a galactic core, it wont work, unfortunately

EDIT : Or maybe you could try adding a galactic core with some DSC defined objects ? I suspect it wont work very well, however. Last year, Jestr and me tried to make some nice fictious nebulae with transparent textures and 3ds models, but the results were disastrous.

[buggs_moran]

Je m'excuse. Le Francais n'est pas mon langue premiere. (hackjob there, 4 yrs of high school French, 20 yrs ago) Sorry you had to go through so much for what you had to say, but it is extraordinarily helpful. Thank you.

[buggs_moran]

D'accord, thanks to Cham's ideas and Selden I am now using pngs through the 3ds to cmod convert. To anyone who uses anim8or, definitely pick up this converter, pngs are so much more usefull and once your model is built CMOD allows you to tweak transparencies, textures, etc. (Most of you veterans know that, but the newbies don't)

My outer disk doesn't have those crisp outer edges anymore. I am going to have to create a new model for the outer gas disk, there is a gap on the outer edge...

I also am experimenting with a a tidally affected star and have added a few stars in the vincinity for fun. My knowledge of stellar movement is limited to High School Astronomy so I am sure I am putting stars in poor places with absurd orbital elements. Time will tell.

[Startyger]

Soooooooooooooooooo, where and when can we get this?


Alas, my mini is clocking 1.2 Ghz ,but my g4 466 minitower has the 128MB video card......... yikes! Apple is getting Intel inside, (i hope Celestia supports the new chipset or at least goes platform indepnedent, i hear it only takes a few lines of code for cocoa apps!) so, i'm wondering if i should invest in a G5? yikes again!! processor upgrade for the minitower? i want a maxed out Celestia!!! which means i have to buy two, one for me and one for my students!!!

[buggs_moran]

I am still working on it. I am learning 3d modeling/textures as I go so it is difficult to say an exact date. Stacted models and rotating surfaces are tricky to get working just right. I am hoping to have a release candidate by the end of the month.