Celestia Forums

a cmod from Dr. Paul Schenk's heightmap

http://stereomoons.blogspot.com/search?q=iapetus

a mesh and normal only preview


THE ZIP File
https://drive.google.com/file/d/0B6ZYAd08tZL-Z1FybGFIMjdIbnc/view?usp=sharing

-- warning
this heightmap DOSE NOT align well with the texture ( cassini & cassini+voyager )

a 2k copy of the heightmap ( 8 bit copy of the 32 bit float data )

Wow! And where can I download this model? Or is it inaccessible?

Fantastic! Thanks for sharing John! Was there some cleanup involved or did I miss the release of some more complete height map? It's definately better than anything I could do. But I managed to align the different patches pretty good with the latest color map by JPL...

This was my try btw, matching this texture: https://photojournal.jpl.nasa.gov/catalog/PIA18436

John Van Vliet wrote:THE ZIP File
https://drive.google.com/file/d/0B6ZYAd08tZL-MVZDcVo3UUdlbE0/view?usp=sharing

Is it possible to reduce the number of polygons to 256 or 300 thousand? To reduce the load on the system.

you used a blur to fill in data

i used "resynthesizer" in gimp
https://github.com/bootchk/resynthesizer

as to less polys
-- maybe ?

John Van Vliet < I have no experience with these utilities. You are better at this than me. You can simply reduce the number of polygons to 300,000 so that I can include Iapetus in "Celestia Origin"?

so you want it BIGGER
it is already as 244615 verts and 244620 faces , but it is UV mapped

John Van Vliet wrote:so you want it BIGGER
it is already as 244615 verts and 244620 faces , but it is UV mapped

I am guided by the number of polygons. Now 489 240, and I ask to reduce to 300 000. For a very detailed model this is optimal. Is it really not clear that I want to increase productivity?

John, can you post this model in .obj format so that I can have my try at correctly orienting the texture?

By the way, I would also not refuse the format .obj. Then we can independently reduce the number of polygons.

Also, if you release the model in obj format, could it be non-UV-mapped? I would rather do the UV mapping myself.

Does the model take oblateness into account? I can't really tell if the polar diameter is shorter than the equatorial diameter on this mesh.

FarGetaNik wrote:Does the model take oblateness into account? I can't really tell if the polar diameter is shorter than the equatorial diameter on this mesh.

There's a difference of only 68 kilometers with a total size of 1492. Personally it seemed to me that everything was taken into account, although it is not easy to notice.

Art Blos wrote:There's a difference of only 68 kilometers with a total size of 1492.

Well it's about 4%. You can definately tell it's oblate when looking at Cassini images, the fact that I can't with this model makes me believe it's not oblate. This is easily fixed if I retain my "Oblateness" parameter in the ssc file.

FarGetaNik wrote:This is easily fixed if I retain my "Oblateness" parameter in the ssc file.

Better this way:

Art Blos wrote:Better this way:

It doesn't matter, the result is the same I prefer oblateness on objects that have 2 identical equatorial axes.