Celestia Forums

It doesn?t make sense.Both Hyperion and Itokawa are irregular bodies.Both have cmod models.However,I can see texture on Hyperion,but not in Itokawa.The Itokawa mosaic texture was from Phil Stooke.What?s going on?

"25143 Itokawa:Itokawa:1998 SF36" "Sol"
{
Class "asteroid"

Mesh "itokawa.cmod"
Texture "itokawa_new_mosaic.jpg"
Radius 0.315

InfoURL "http://en.wikipedia.org/wiki/25143_Itokawa"

# Osculating elements from HORIZONS
EllipticalOrbit
{
Epoch 2453625.5 # 2005 Sep 12--Hayabusa arrival
Period 1.523231392
SemiMajorAxis 1.323849003
Eccentricity 0.2801215972
Inclination 1.622265921
AscendingNode 69.09461308
ArgOfPericenter 162.7594572
MeanAnomaly 310.6795025
}

# Retrograde rotation pole with RA 90.53 and Dec -66.30
# From "Pole and global shape of 25143 Itokawa",
# Demura et al, Science, 2 Jun 2006
BodyFrame { EquatorJ2000 {} }
UniformRotation
{
Inclination 156.30
AscendingNode 180.53
Period 12.132
}

Color [ 1 0.96 0.80 ] # Approximation based on natural color images
LunarLambert 0.5 # Approximate a dusty surface

# Align model with Celestia's coordinate system
Orientation [ 90 1 0 0 ]

Albedo 0.53
}

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I put in textures>hires

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The system default asteroids.ssc

I think this was discussed once before.
The model file has no surface texture specified in its material declaration, so a Texture statement can't apply one to the mesh.

So I will have to wait for a mesh that have a texture specified?

You could convert it from binary to ASCII and edit it.

I seem to have a vague recollection that Chris said that the mesh may simply be too big and detailed for texture maps to work well, but I could be mistaken. Don't let that stop you from trying!

Some time ago, I have described in CelestialMatters how I am doing things with great success

Itokawa, Phobos and friends...
http://forum.celestialmatters.org/viewt ... 37&start=0

Here I show how to get rid of the polar pinch effect within the same technique:
http://forum.celestialmatters.org/viewtopic.php?t=339


Here is a video of my phobos modelling result using just clever tesselations from scientific data
http://forum.celestialmatters.org/userp ... opinch.avi

But I am not producing downloads for "end users" at the moment.

Fridger

I think you don?t understand what I mean...Hyperion is a irregular body,so is Itokawa.However,I was able to change the texture in Hyperion but not in Itokawa.Does it mean that the Itokawa texture from Phil Stooke is not formated to Celestia?What I have to change?Also Celestia never finds the textures in the hugh textures folder when they are with the same name in med and hi res.The correct answer should be first med res,press capital R and the texture in hires is exhbited,but Celestia can?t find it!

I had a similar problem with Itokawa as well. Itokawa and Mimas are both meshed bodies for which I've had difficulties texturing. I think if you use a lower-poly mesh, it works a little smoother. I haven't ever succeeded getting Itokawa's texture to work due to a lack of trying so I don't know how well that will work for you.

Try using the lowest-poly mesh. See if it helps?

I?m already using the "itokawa.cmod" low poly mesh.

That's sound like no UV map...

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What exactly is a UV map?Ultraviolet map?
Well,we also have a preliminary map of Helene,that is in my med res textures,but in this case,it?s squared and not retangular,so it?s in the wrong format!
All these preliminary maps should be from Phill Stooke.
I am surprised that we have nothing similar to Prometheus and Epimetheus...

danielj wrote:What exactly is a UV map?Ultraviolet map?
Well,we also have a preliminary map of Helene,that is in my med res textures,but in this case,it?s squared and not retangular,so it?s in the wrong format!
All these preliminary maps should be from Phill Stooke.
I am surprised that we have nothing similar to Prometheus and Epimetheus...

UV mapping -> http://en.wikipedia.org/wiki/UV_mapping
Without that, there is no room in texture's assignment, so the Itokawa texture isn't displayed. Prometheus, Epimetheus and Helene are UV mapped, instead. Whether textures are in 1:1 or 2:1 ratios, is neglegible for your graphic card: it does handle both.

Well,I changed Helene texture with sucess.I now know that I have to wait for Itokawa.But if there is around a parcial texture of Helene,where are new textures of Epimetheus and Prometheus?Cassini did a lot of flyby of these moons and I think Phil Stooke should be doing something with this.However,I can?t find it anywhere...

The link to Phil Stooke?s maps of small worlds is broken...

http://www.unmannedspaceflight.com/inde ... &start=285
We even have a preliminary map of asteroid Stein.Was it UV mapped?
I don?t understand why we have preliminary maps for asteroids that are flown ONCE,while Prometheus and Epimetheus that received at least half a dozen flybys,don?t have one.We are still restricted to Voyager 2 MAPS!

But in fact,this crude texture map is useless without a data in ssc format and the corresponding model.I search Google and find nothing.Is there any available?