http://forum.celestialmatters.org/

Modified Titan
http://forum.celestialmatters.org/viewtopic.php?f=9&t=461
Page 1 of 1

Author:  arctodus [ Sat, 16-03-13, 11:03 GMT ]
Post subject:  Modified Titan

:) Hi all, I decided to slightly modify Titan. For this i've created normal map and specular map. A little modified surface map and added transparent clouds. Although I am do not pretend to be scientific, but think that Titan looks better with it than without :) .

Image

Image
Saturn rising without clouds
Image
through the clouds
Image

Sorry for my bad english :mrgreen: . Best regards. Max.

Author:  t00fri [ Sat, 16-03-13, 14:52 GMT ]
Post subject: 

Max,

your modified Titan looks admittedly nice. Yet the scientific results clearly showed that its clouds are essentially NOT transparent to visual light. They are becoming transparent, when infrared filters are used. For Celestia the rendering is based throughout on visible light, hence there Titan's clouds should remain an untransparent orange. In celestia.Sci, I pursue a much wider approach implementing multi-wavelength astronomical data. Here one might interpret your views as infrared filtered.

Perhaps near the poles there is less smog. See this thread about my respective work by implementing a specular map for this huge Titan lake, called Kraken Mare. Here a specular reflection has indeed be seen.

http://forum.celestialmatters.org/viewtopic.php?t=358
Here is a view that shows the specularity from Kraken Mare near the pole:

Image

Or here Lake Ontario near the pole:
Image
Image

Which surface textures did you use? Perhaps you know that I did the official one in the Celestia distribution, as well as various later ones (also discussed here in the forum). My Titan textures were circulated both at ESA and in the Planetary society.

After we have now learned that there are indeed lakes on Titan, a specular map might seem reasonable. Yet mostly, there is no direct sun light reaching the surface. Hence there is practically no specularity in reality since the small amount of diffuse light reaching the surface is practically undirected...

How does the backscattering of sunlight look after your modifications of Titan's atmosphere?? Here we do have very precise data. This is a VERY critical test.


Fridger

Author:  arctodus [ Sat, 16-03-13, 15:31 GMT ]
Post subject: 

Thanks for the explanation, your research in this field is very interesting. I admit my mistake - specular reflection is unnecessary in this case. But what about the normal map? Does it make sense, in relation to Titan?

Max

Author:  t00fri [ Sat, 16-03-13, 15:52 GMT ]
Post subject: 

arctodus wrote:
Thanks for the explanation, your research in this field is very interesting. I admit my mistake - specular reflection is unnecessary in this case. But what about the normal map? Does it make sense, in relation to Titan?

Max


A normal map does not make too much sense, since 1) the elevations on Titan are mostly very low and 2) there are no respective measurements!

You are sure aware that elevation map data (that are inputs for the normalmap) are entirely independent from the surface texture data. You cannot generate them with reasonable accuracy from shaded surface map data. Notably on Titan there is little shadow in the diffuse light on the surface. I know of course that there are programs claiming to generate bumpmaps without dedicated measurements. Yet that is not what we usually do at Celestia.

A long time ago, I also made a normalmap for Titan --just for fun--:

Here are two such views:

[click on images for a larger view]
Image
Image

In summary, playing with Titan landscapes and the special light and atmospheric conditions may be great fun. Yet more serious activities will have to take recourse to a wealth of data from the Cassini mission.

Yes I have done quite a lot of work with Titan over the years.

Fridger

Page 1 of 1 All times are UTC
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/