Celestia Forums

Before i imported my L-5 addon, i did a test with a model of a Space Power Satellite.
to my horror, the entire solar cell structure disappeared! and the back of the cell was invisible!
my earthlink account is dead, got DSL WWOOHOO!!
check here for updates.

Here also is the pics of my problem, can anyone help?

http://photos.yahoo.com/beowulf_i_am

Beowulf? Joe?

Where are the pictures that are supposed to show the
problem?

When I click on the link in your message, all I see are
pics of some big, ugly, bearded guy and his dogs.

Oops... Sorry. There ARE also some pictures of a pretty
lady too.

Take care, Bob

when i posted the message i hadn't added the pic yet, didn't expect some one to reply so quick.
http://pg.photos.yahoo.com/ph/beowulf_i ... /my_photos

try that.
ignore the ugly guy thats me.,. the dogs mine, aint he cute?

This latest link takes me to a site which says:

The File You Are Looking For Is Inaccessible

The dogs ARE kinda cute though.

Thanks, Bob

ok try this.
http://pg.photos.yahoo.com/ph/beowulf_i ... pg&.src=ph

Beowulf01 wrote:http://pg.photos.yahoo.com/ph/beowulf_i_am/detail?.dir=729f&.dnm=3311.jpg&.src=ph

Sorry Beowulf...

Same problem as the last link. Access is denied. Maybe you
have to be a member in order to view the page?

Take care, Bob

BOB, i had to create a new web page account, my old one is currently unavailable.

http://home.centurytel.net/harley002/SPS-1.jpg
try there, that is what i got with my first structure, I had a single plane object as the solar cell. everything else loaded OK except that.
I got frustrated when This Form was unavailable, so i just changed my structure.
you can see that in the other pictures.

got any ideas why that happened?

I am hoping that i wont have problems with my L-5 addon.

thanks
Harley

Beowulf01 wrote:got any ideas why that happened?

Beowulf,

Do I understand you correctly here? This is a model, yes?

If so, it looks as if your model is missing some textures.

Did you create this with Anim8or? If so, you need to associate
the appropriate textures for the model in Celestia's
textures\medres folder so that the textures can be found
and applied to the model.

Now, believe me I am NO expert here. You may do better to get
an answer from someone who knows his modeling. Try jestr or
Bob Hundley (both members here)

Maybe I'm just mis-interpreting your image, but What I see
in your picture looks like Celestia can't find all of the
textures.

Hope that helps, but AGAIN, I'm no modeling expert. Could also
be caused by old graphics drivers that need to be updated.

Can you give us a better explanation of what's involved here?
Is this a model? What graphics card are you using? Where
are the textures? ETC...

The more information you can give, the better your chances
for an intelligent answer from some of the wizards who live
here in Celestia Land.

Nice to see the image finally though.

EDIT: I looked at the OTHER images in the directory you
pointed me to, and THEY looked great. What did you do
differently with this particular image?

Take care, Bob

yes this is a model, it is intended to be bundled with my L-5 add on.

I created it with Rhino3D Vers2.
now if Celestia can find a texture it just shows up as plain white texture? right? I seen it before.

as for graphics card
i got nvidia 4600 Ti with the latest drivers, needed that for Half Life 2....hheheh

Teh textures are in the right place and are the correct size. they should show up. what i was thinking is the "solar cell"is composed of a single plane, i was wondering f there is some setting or error i ran into with single plane structres..?

the other images, i created later, i took the transmitter antenna structure, enlarged it, and changed the textures to the solar cell ones.

Glad you liked them...
try the same site again to see the L-5 images ... these are images from my modeling programs render engine, not Celestia.

thanks

Harley,

Single planes work just fine. I use them all the time for "billboards" in Celestia.

However, you do have to be careful that the surface normals point in the correct directions. Unlike many 3D display programs, Celestia uses the surface normals to decide whether to draw a surface. If they point away from the observer's viewpoint, the surface won't be drawn at all: it'll be invisible. You'll see through it to whatever's behind it. That looks like what's happening in your sample image.

If surface normals aren't specified explicitly in the model, the order that the vertices are specified in the mesh's vertex lists determines which sides of the triangles are visible.

Does this help?

I think so, ill try working on it later today, after work. thanks.

uh, well geuss that aint working,
could you explain in a bit more detail?

Some examples of models which use surface normals to make them visible only from one side are at http://www.lepp.cornell.edu/~seb/celestia/billboard.html#7.2

The spheres used to hold the all-sky maps have their surface normals pointing inward, toward the center of the sphere. The maps are entirely visible when seen from the inside of the sphere, but only half-visible when seen from the outside.

They were created using Anim8or.
Most of them can't be imported into 3D modelling programs because they were damaged when I edited them to change the names of their surface texture images.

I have a simple CMOD model at home that illustrates the same effect by reordering the vertex list. I'll upload it this evening.

Sorry about the delay.

Here's an ASCII CMOD model definition for a square plane.

Harley,

Selden's advice will show you how to use a single-plane
model, but I don't think that this is what you want is it?

Sounds like you need to create the model with multiple
planes?

BTW, I saw your other L5 pictures... Good stuff.

Take care, Bob

Bob,

My intent was to show how surface normals and ordering of vertices in a model can affect the visibility of a surface.

Unfortunately, I am not at all familiar with how those model elements are controlled in most 3D graphics packages.

The one 3D modelling program that I'm familiar with is Anim8or (freeware for Windows), which has a relatively simple user interface -- just right for us old geezers who are too impatient to spend months learning something complicated!

*ahem*

At any rate, Anim8or v0.85 includes in its Edit menu the two options "Flip Normals" and "Fix Normals" which can be used to control the directions that the surface normals point. I'd be very surprised if equivalent functions aren't available in other 3D design programs.

selden wrote:My intent was to show how surface normals and ordering of vertices in a model can affect the visibility of a surface.

And you did this - as always - in a way which us geezers
can understand...

You already know that I'm Brain-Dead, but Beowulf01 might
actually understand what you're saying. I'm just keeping
this thread going in the hope that Jestr or Mr. Hundley can
offer knowledgable advice.

Take care, Bob

I dont really know what is happening here either mate.Obviously the normals are flipped,but why?It could be introduced in the conversion process,it could be down to different parts of the model having different centres.If I had the model to work with I might be able to be more helpful.All the best Jestr

I want to thank you all for the help,
I do understand some of what selden has written.

jestr, I will upload the models to my site here In a bit. It is rather frustrating, I have been using Rhino 3d Version2 for a few months.
I'm rather experienced with doing polys, but never had to do the Mesh work.
so I'm a Huge newbie there. This Form has be unavailable at times and it drove me crazy, i really appreciate the help.
Let me know what you find.


IF.....................IF, this pans out i have several models id like to do, some partly done.
They all are, models that are grounded in real research and have actually been visualized by engineers.
So far i have small list

1 A Beral sphere Space habitat= a Bigger version of the L-5
2 A Much Larger habitat which is cylinder shaped
3 a Orion , bomb driven space craft
4 several star ships based on the British Interplanetary society's Daedalus and ram scoop ships.

uhhh the files are WAY too big to post to my site.. they run in the 21MB range.........

how could i get these to ya, jester?