ringworld

[muteinvert]

so ive read this book called ringworld, and thought id be cool to have it in celestia.

i didnt make the exact one, its like 1/10th the radius, but for that i also need to make a star about 150% the size of jupiter.

but they never thought of explaining what the stuff in stc files means, like

RA, means radius, but what units is it in, km or au?
whats DEC and appmag?
"distance" from what?
and shouldnt there be some variable that says the position of the star?

now onto ssc files:

is there a way to make orbits non-elliptical?
can you position the center of the planet(in this case ring) exactly in the same place as the star?

[granthutchison]

RA is Right Ascension, Dec is declination, both in decimal degrees - these define the position of the star in the sky. Distance is distance from the sun in light years, and together with RA and Dec it defines the star's 3d position.
AppMag is the apparent magnitude, a measure of the star's brightness. Celestia computes the radius of the star on the fly, from its distance and apparent brightness.

To centre a "planet" on a star, just use a very very small orbital radius.

The Ringworld has been built before in Celestia - you should try searching the forum, and you should find a reference to it.

Grant

[Guest]

hmm yeah, someone alreayd thought of that. but mines gonna be better. if i finish it.

[muteinvert]

damn forgot to put my name

[marc]

Ill warn you now, there are a lot of tricks to getting it right, and your in for a long haul starting from scratch.
I spent many hours getting the scale right and the movement of the shadow squares and shadows working and correct. The hardest bit was just getting the ring to display correctly in celestia.
One thing I need to improve on is the surface texture, which needs much smaller oceans and much more land. An atmosphere would be nice too.









Your welcome to try and improve mine but if you want to have a go yourself here is where I started.

http://www.alcyone.com/max/reference/sc ... world.html

[Guest]

I read the book when was teenager, and enjoyed Ringworld much, because of its inmense horizons and posibilities. I was delighted when discovered your implementation, but I agree the texture must be improved (for accuracy with the book, I think, ?where are the two inmense oceans?). Perhaps it's one of the first things I would try when I have more confidence with the program (and a lot of time, too...). But thanks a lot for your work, marc!!

[jamarsa]

Sorry, I have a new computer at home, and didn't auto-logon until I noticed i wasn't able to edit my previous post...
I was remembering the references to the Arc in the book, and was about to try to see it from the Ring surface...

Another thing I distaste is the placement in the solar system. I prefer to leave the Solar System as undisturbed as possible, because there is a lot of work here yet, and the insertion of Ringworld disturbs all. Perhaps you should place it where the book says, in a star nearer of the Galactic center. Any candidates??

[granthutchison]

Not nearer the galactic centre!
The Puppeteer fleet was fleeing the Core Explosion when they discovered the Ringworld, so they were moving away from the galactic centre.
The location and nature of the Ringworld star is actually pretty well defined in the books - it's to the galactic north of Sol, and even has a Puppeteer catalogue number!
Here's a definition to place in an stc file:

Code: Select all

300000 "EC-1752:Ringworld"
{
RA 192.25
Dec 27.4
Distance 201
SpectralType "G3V"
AbsMag 4.89
}


[MrBatman]

Anyone have a link to the earlier Ringworld implementation? I can't seem to find it.

Edit: Nevermind, I found it. It looks awesome! Doing an atmosphere would be extremely difficult; you'd almost have to have a separate atmospheric mesh sitting inside the Ringworld's mesh, I would think. Would also be nice to have the 1600km walls on the side, and attitude thrusters on the backside. Some more backside detail, too.

I used to have a link to a website that had all the technical specs for the Ringworld. If you're really interested in pursuing this, muteinvert. I strongly suggest you read Niven's sequel, "The Ringworld Engineers."

[marc]

Another thing I distaste is the placement in the solar system. I prefer to leave the Solar System as undisturbed as possible, because there is a lot of work here yet, and the insertion of Ringworld disturbs all. Perhaps you should place it where the book says, in a star nearer of the Galactic center. Any candidates??

I just had another look at whats in ringworld_1.1.zip There are two ssc files in the extras directory. One put the ringworld around Sol and the other around HD512. Delete the ringworld_sol.ssc file then go have a look at HD512.

I originally put the ringworld around HD512/HIP772. Its a G3V star 200.592 ly from Sol and is perpendicular to the galactic plane. (though i think to the south) The problem was that Celestia crashed whenever I travelled to the ringworld from sol. So I put it around sol so i could at least have a look at it before my computer crashed.

I've realised later that a lot of people did not experience the crashes that i did. Also this same crashing issue with my computer has come up again when using Jack's "Positional ssc for everything* on the moon's surface!".
http://www.celestiaproject.net/forum/viewtopic.php?t=2432

Ill see if i can reproduce this problem again with both add-ons then submit it as a bug.

Anyway it looks like its time for a new version. Ill set the default install to another star, and change the texture. Someone else mentioned that the albedo needs changing too. I want to change the texture too, the only problem is I cant decide what the texture should look like. (suggestions?)

I like the look of this one.
http://www.rahul.net/rootbear/graphics/ ... d/rw0.html


I might have a go at putting in the fist of god, but the shadows might look shit going over it. Does anyone have its dimensions?

For reference here's the old ringworld thread:
http://www.celestiaproject.net/forum/viewtopic.php?t=324

Its been a while since I read the books so references to relavent pages would be useful.

[jamarsa]

Mmm, I remember now the crashing issue... and your change to the solar system that fixed it. I think (don't remember exactly now) it crashed to me too.

This new texture is better; there is more land, as that's was the purpose of the Ringworld, to create a lot of space for living humans (or Pak Protectors).

The Fist of God was really small compared to the whole structure; it was seen only because they landed very near to it, and it was the only mountain, enhancing the heightness effect. I have the book stored (I am a compulsive collector), so i will look at it this weekend for measurements.

[marc]

I havnt made that texture, its an image generated by someone else (its not Celestia). I'll the email the author and ask if he wants to donate his surface texture.
If thats not suitable can anyone think of a way to generate something like this? Or a suitable substitute texture.

Mr Batman, I tried adding the walls but the hieght of the walls compared to the width of the ring is just to small to represent in a 3ds mesh. Same goes for the thickness of the ring as well.
It might be possible to put one small area on the ring that has its own models to give extra detail.

[ElPelado]

i downloaded it yesterday, and it crashes when going to hd 512.

[marc]

Ah excellent, good to know it wasnt just me.
Chris mentioned once that this might be a serious bug, so I thinks its time to track it down.

Jamarsa and ElPelado if you can help me out it would be great:

Can you please delete the ringworld_sol.ssc in your extras directory, then confirm that the crash happens on approach to HD 512. Can you also tell me what you see at point of crashing.
I dont get to see anything, just stars and the distance to HD 512 is 1.097 lightyears
Then post your system specs and openGlInfo (under help in celestia) and also what version of Celestia you have.

these are my specs:

Athalon 1Ghz 512M
Geforce2 MX400 64M
Celesita 1.3.0

opengl32.dll 5.1.2600.1106

and openGL info
Vendor: NVIDIA Corporation
Renderer: GeForce2 MX/AGP/SSE/3DNOW!
Version: 1.4.0
Max simultaneous textures: 2
Max texture size: 2048

Supported Extensions:
GL_ARB_imaging
GL_ARB_multitexture
GL_ARB_point_parameters
GL_ARB_texture_compression
GL_ARB_texture_cube_map
GL_ARB_texture_env_add
GL_ARB_texture_env_combine
GL_ARB_texture_env_dot3
GL_ARB_texture_mirrored_repeat
GL_ARB_transpose_matrix
GL_ARB_vertex_program
GL_ARB_window_pos
GL_S3_s3tc
GL_EXT_abgr
GL_EXT_bgra
GL_EXT_blend_color
GL_EXT_blend_minmax
GL_EXT_blend_subtract
GL_EXT_clip_volume_hint
GL_EXT_compiled_vertex_array
GL_EXT_draw_range_elements
GL_EXT_fog_coord
GL_EXT_multi_draw_arrays
GL_EXT_packed_pixels
GL_EXT_paletted_texture
GL_EXT_point_parameters
GL_EXT_rescale_normal
GL_EXT_secondary_color
GL_EXT_separate_specular_color
GL_EXT_shared_texture_palette
GL_EXT_stencil_wrap
GL_EXT_texture_compression_s3tc
GL_EXT_texture_cube_map
GL_EXT_texture_edge_clamp
GL_EXT_texture_env_add
GL_EXT_texture_env_combine
GL_EXT_texture_env_dot3
GL_EXT_texture_filter_anisotropic
GL_EXT_texture_lod
GL_EXT_texture_lod_bias
GL_EXT_texture_object
GL_EXT_vertex_array
GL_EXT_vertex_weighting
GL_IBM_texture_mirrored_repeat
GL_KTX_buffer_region
GL_NV_blend_square
GL_NV_fence
GL_NV_fog_distance
GL_NV_light_max_exponent
GL_NV_packed_depth_stencil
GL_NV_pixel_data_range
GL_NV_point_sprite
GL_NV_register_combiners
GL_NV_texgen_reflection
GL_NV_texture_env_combine4
GL_NV_texture_rectangle
GL_NV_vertex_array_range
GL_NV_vertex_array_range2
GL_NV_vertex_program
GL_NV_vertex_program1_1
GL_SGIS_generate_mipmap
GL_SGIS_multitexture
GL_SGIS_texture_lod
GL_WIN_swap_hint
WGL_EXT_swap_control


Ill see if I can identify exactly what it is about the models/textures/ssc that is making it crash by doing some pruning of the ringworld ssc file. And some other fiddling.

I have already discovered that it is possible to get to HD 512 if planet rendering is turned off. It can then be turned on again after arrival and the ringworld works fine.

[JackHiggins]

I've realised later that a lot of people did not experience the crashes that i did. Also this same crashing issue with my computer has come up again when using Jack's "Positional ssc for everything* on the moon's surface!".
http://www.celestiaproject.net/forum/viewtopic.php?t=2432

Marc, i've never had any problems using my ssc for everything* on the moon. When does it crash, exactly?

Maybe it's because there are so many objects in a relatively small area, or something like that....? That's the only thing I can think of, because apart from that it's just a regular ssc file...

[ElPelado]

first of all, i only copyed the *.ssc file of HD 512, not the sol one.
here is my system:
second: when i am on sol, i pres [enter] hd 512 [enter] and when aproaching the star appears a windows message that says that celestia must be closed.
y tryed going to the star without planets and enabling planets rendering after getting there, and it worked.

Pentium 4 1.5Ghz 128M
Geforce2 MX400 64M
Celesita 1.3.1pre3

opengl info:
Vendor: NVIDIA Corporation
Renderer: GeForce2 MX/AGP/SSE2
Version: 1.4.0
Max simultaneous textures: 2
Max texture size: 2048

Supported Extensions:
GL_ARB_imaging
GL_ARB_multitexture
GL_ARB_point_parameters
GL_ARB_texture_compression
GL_ARB_texture_cube_map
GL_ARB_texture_env_add
GL_ARB_texture_env_combine
GL_ARB_texture_env_dot3
GL_ARB_texture_mirrored_repeat
GL_ARB_transpose_matrix
GL_ARB_vertex_program
GL_ARB_window_pos
GL_S3_s3tc
GL_EXT_abgr
GL_EXT_bgra
GL_EXT_blend_color
GL_EXT_blend_minmax
GL_EXT_blend_subtract
GL_EXT_clip_volume_hint
GL_EXT_compiled_vertex_array
GL_EXT_draw_range_elements
GL_EXT_fog_coord
GL_EXT_multi_draw_arrays
GL_EXT_packed_pixels
GL_EXT_paletted_texture
GL_EXT_point_parameters
GL_EXT_rescale_normal
GL_EXT_secondary_color
GL_EXT_separate_specular_color
GL_EXT_shared_texture_palette
GL_EXT_stencil_wrap
GL_EXT_texture_compression_s3tc
GL_EXT_texture_cube_map
GL_EXT_texture_edge_clamp
GL_EXT_texture_env_add
GL_EXT_texture_env_combine
GL_EXT_texture_env_dot3
GL_EXT_texture_filter_anisotropic
GL_EXT_texture_lod
GL_EXT_texture_lod_bias
GL_EXT_texture_object
GL_EXT_vertex_array
GL_IBM_texture_mirrored_repeat
GL_KTX_buffer_region
GL_NV_blend_square
GL_NV_fence
GL_NV_fog_distance
GL_NV_light_max_exponent
GL_NV_packed_depth_stencil
GL_NV_pixel_data_range
GL_NV_point_sprite
GL_NV_register_combiners
GL_NV_texgen_reflection
GL_NV_texture_env_combine4
GL_NV_texture_rectangle
GL_NV_vertex_array_range
GL_NV_vertex_array_range2
GL_NV_vertex_program
GL_NV_vertex_program1_1
GL_NVX_ycrcb
GL_SGIS_generate_mipmap
GL_SGIS_multitexture
GL_SGIS_texture_lod
GL_WIN_swap_hint
WGL_EXT_swap_control

[Guest]

Jack

Using my primary PC (specs above). I can vew it for a little while at about the distance of your screen shot on the add-on forum. As im rotating the moon around with the mouse it crashes (ie celestia freezes). It seems as the bug is somehow related to the magnitude limit setting. If i have it up high (15) I can make is crash every time within a few seconds, if I have it down low it will not crash. It does not seem to be related to the labels, and using the _ast.ssc gives the same results.
heres a screenshot of what I see just before the crash. Some of the surface objects also seem to flicker on and off.

here is a screenshot jsut before the crash occurs
http://mostlyharmless.sourceforge.net/p ... ncrash.jpg


Ive just tested it on a second computer (specs below) and it seems to work fine. It crashed once and I tried several times to reproduce it and couldn't.

As both the ringworld and your lunar objects have a lot of entries in the ssc files I thought the problem might be related.
The second computer however crashes the same as my first when viewing with my ringworld.


Windows 2000 server
Celeron 900Mhz 256M
Celestia 1.3.0

opengl32.dll version 5.0.2195.2676

Vendor: SiS AGP
Renderer: 630/730 / MMX
Version: 2.03
Max simultaneous textures: 2
Max texture size: 1024

Supported Extensions:

GL_ARB_multitexture
GL_EXT_abgr
GL_EXT_bgra
GL_EXT_compiled_vertex_array
GL_EXT_packed_pixels
GL_EXT_texture_object
GL_EXT_vertex_array
GL_SGIS_multitexture
GL_WIN_swap_hint

[marc]

Damn stupid computer lost its cookies. (the above was me)

Thanks El Pelado, thats exactly what happens to me.
Ive played with the ringworld a little further, when I reduce the number of ring sections to 10 then the approach works. Bring it back up to 20 ring sections and the same crash happens. The model has 360 ring sections and they all share the same texture, could this be a factor? Ill try doing it with just the ssc file and no textures or meshes.

[marc]

I deleted the 3 textures that make up the ringworld and the crash still happens.
Next I removed all the references to the meshes and textures in the ringworld ssc file. It still crashes.

The ringworld looks funny naked however.


El Pelado, can you confirm that if you zoom out after doing the render planets trick that it crashes again?

[ElPelado]

yes marc, it also crashes when goinf out from it. the difference is that when going to the star, this happens:


and when going out from the star, to close the program i must use the Ctrl+Alt+Delete command to close the "Celestia[Not responding]"


i rememebr on add-on that i wanted to try once... it was an elevator or something like that. it was like an elevator to a space station orbitin erath. the point is that it also was fromed by lots of *.3ds parts. i have neber seen it yet. it always crashes. maybe there is a problem when using lots of 3ds models. i tryed the elevator with only som of the parts and it didnt crashed.