Celestia Forums

unless you've had the same issue...

I added some Nebulas and systems to Celestia over the weekend, a lot of, like V380, the M104-Sombrero, M31-Andromeda, blablabla, most of them work, some don't. Strange...

The problem I have for some of them, like for example with M104-Sombrero, is that I can select and travel to it, but I do not see what I 'm supposed to. I only see 2 lines under each other that represents all alphanumeric characters, and I can turn it upside down, zoom it, whatever, wihch makes me think it's something to do with either the model (3DS) or the way I set it up.
So, it looks like something close to this:
121234567890ABCDEFGHIJ
KLMNOPQRSTUWXYZ?./&?"'

2 big white 3D lines in the middle of the cosmos like that... but no Sombrero, nothing. And I have that issue for some of my newly installed stuff (M31 too).

Also, is it normal that some nebulas do not have a 3DS model? I'm just wondering...

Anyone experienced that? or is familiar enough with 3DS stuff and knows
what might have caused this?

Thanks a lot for your help.
Cheers,
DSF.

DSF,

I've seen the same thing (images of text strings) when there was something wrong with the image file. Unfortunately, I can't remember the details right now. I don't think it was due to the file missing entirely (or misnamed) -- that usually results in Celestia displaying the image that it loaded for the previous nebula.

You might try turning on the new "console log" with a ~ (tilde = shift ` ) Maybe it'll include a relevant complaint. (It doesn't always, but Chris is usually good about adding error messages when a particular type of I/O failure is identified.)

Added slightly later:

There are times when a Nebula definition without a Mesh is convenient. It can be used just to mark a location in space, or it can be used to provide alternative names for the same body.

A Nebula definition containing a Mesh lets the designer display a picture in space. However, the center position of the Mesh may not be near the astrophysical center of body. A Nebula definition that doesn't include a Mesh can be used to mark the body's actual location. Also, some pictures include several different nebulae in the same image. Additional Nebula definitions can be used to mark them.

Celestia doesn't (yet?) allow multiple Nebula names within the same declaration in a DSC file. (It does for stars in STC files.) Like most stars, most nebulae have several different names because they're listed in several different astronomical catalogs. (Messier, NGC, IC, etc). Using several different Nebula entries gets around this limitation.

Does this clarify things?

Hey Selden ,

well, strange 'coz I can see and open the DDS with ifanviewer so it seems the image is at least not corrupt.

I'll give a try to the console as soon as I get home (I'm actually working now...).

Also, what you tell me is that maybe I have those nebulae defined into several catalogs at the same time, and that might be the problem?
I'll check that too.

Will let you know,
Tx,
DSF.

DSF,

Actually my "added later" was answering a different question that you might not have been asking:

"Why do some Deep Space Catalog files have several Nebulas defined, many of which do not have 3DS Meshes listed?"

Celestia does not have any problems loading more than one object with the same name at the same location. It just "does it". The result may look a little strange, but that's just due to the order the objects are drawn. It doesn't totally scramble them or draw the alphanumeric object you're seeing.

DSF,

Just because one image viewer can display an image does not mean that another one can.

I really don't know much about DDS texture file formats, but I read somewhere that Celestia cannot interpret DDS images which do not include mipmaps.

As I now vaguely recall, when I saw the alphanumeric images, I was using PNG files created by NetPBM from grey-scale images. Celestia didn't like them at all. Lately I've been using either ImageMagick or nvdxt to create the final image files. They work fine.

well, they should work though... there made for Celestia apparently... so..

and I even think I found many of them thanks to your links.

Anyway I'll do some research and let u know.

cheerz

selden wrote:I really don't know much about DDS texture file formats, but I read somewhere that Celestia cannot interpret DDS images which do not include mipmaps.

selden, where did you get that from?
I'm always creating my DDS VT tiles without mipmaps because it's an unused overhead there, and I never encountered problems.
If you remember the source (and if that's actual or obsolete now) give me a hint.

maxim

Maxim,

That's great!

I read that comment in a "readme" that was in a toolkit created by one of the members of the forum. I'm guessing that either he was mistaken about the cause of a problem he was having with the software or he made a mistake in what he wrote. (As with many here, English is not his "mother tongue".)

I'll let him know so he can either correct the sentence or track down the actual problem.

Thanks!