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View Full Version : Tutorial - making a ringed gas giant.



starbase1
02-14-2006, 01:47 PM
Hi All,
I have just posted my first attempt at a Lightwave tutorial.

It describes how to make a gas giant with a detailed ring system, using seriously efficient image maps, (just 1 pixel wide!).

I have not yet linkd it into the rest of my pages as I'd like you guys to try and find any mistakes first!

It's here:
http://www.starbase1.co.uk/tutring.htm

And here are a couple of images from the finished result:

A Mejias
02-14-2006, 02:18 PM
From a quick look it looks good! Like an anvanced version of the one that was in the old LW 4.0 or 5.0 manuals. :)

Gettarobox
02-14-2006, 06:36 PM
nice tutorial.
is that what it would be like in a photo real sense? i always think of making big cartoony rocks flying around the planet. i am starting to see the benefits of looking at things in as realistic a way as possible for certain projects.

starbase1
02-15-2006, 12:44 AM
That's very difficult to say... I think the look is pretty realistic, the most obvius improvement would be to use a more detailled ring map. I have done images usig the full voyager occultation data for saturn, and it looks really good, though for more distant view like these you need huge anti aliasing levels.

You can certainly recreate the kind of image that Cassini is currently returning:
http://saturn.jpl.nasa.gov/multimedia/images/images.cfm?categoryID=5

The view from inside the rings is VERY difficult to judge. But it's certainly nothing like 'Star Wars'. The total mass in the Saturn ring system is that of a small moon, , but spread over a HUGE volume. The typical ring chuunk is about car to house sized, and made of dirty ice, so they are not very close together.

I have tried particle based rings but the particle limit was way too small, and I could not work out an elegant way of blending a near and far system.

I have not covered an atmosphere here, (there are earth tutorials out there that do this well), and the other thing that would help a lot is to use radiosity when the sun / ring angle is high. It may sound daft to use radiosity on a planet, but there are some great photos showing how strongly the ring system can illuminate the rear of the planet at mid latitudes.

Nick

Silkrooster
02-15-2006, 01:24 AM
Hey, congrads on your tut. I placed a link for it on my wiki hopefully it will help in the future. http://www.silkrooster.com/wiki/index.php?title=NewTek%27s_Lightwave_Community#Tut orials
Silk

starbase1
02-15-2006, 02:30 AM
Thanks for the link! Always nice to get one! :D

And on a different subject, I'll do some more thinking on making a view from within the rings. While brute force with swarms of particles / HV's clearly wont work, it should be possible somehow. I think the most productive line of attack might well be to make the polygon based solution fade to nothiing close up by means of a gradient... After all, if the particles are reasonably far apart you don't need to model very many of them...

Nick