FINAL release of new Mercury model DONE!!

[bh]

Yep..you lost me there..hehe!...Good luck!

[ElChristou]

...However, wouldn't this kind of positioning and El Christou's desire to
position the spacecraft correctly require an XYZ file?

I know nothing about xyz files so I cannot say yes or no, but for a geostationary position + slight rotation on main axis I thought a classic ssc would be enough... Now if someone have a solution using a xyz file, please your are welcome.

**

Sundog, I don't know how react the meshcenter command in that case, but it's not the desired effect, the RotationPeriod don't act anymore; using the orientation trick (jestr/selden one) + little modif + eliminating the RotationPeriod command result in the same...

**

After spending such amoung of time on the model, I cannot believe I'm stuck at this point... Seems my last chance is to find a pc, install celestia to use the edit mode on the model...

**

Yep..you lost me there..hehe!...Good luck!

Sorry guys, perhaps my posts are not clear enough...

[sundog]

Sundog, I don't know how react the meshcenter command in that case, but it's not the desired effect...

I misunderstood what you wanted, the model was slightly eccentric about its axis, MeshCenter fixes it.

I could be wrong again, but see if this is what you are looking for.

Code: Select all

"Liberty Bell 7" "Sol/Earth"

{
   Class         "spacecraft"
   Mesh         "lb7.cmod"
   MeshCenter      [0.0 0.0 0.003]
   Radius         0.003


   # approx position at 2'30" from take off before extention of periscope:
   LongLat         [ -79.8 28.3 70 ]


   Obliquity      260
   RotationPeriod      0.09
   PrecessionRate      360.9856414795
   EquatorAscendingNode   -25

   Albedo         0.10
}

sundog

[BrainDead]

I misunderstood what you wanted, the model was slightly eccentric about its axis, MeshCenter fixes it.

I could be wrong again, but see if this is what you are looking for...

ElChristou... Sundog...

I installed the SSC Sundog posted above, and it looks like what
your are after to me. The placement and attitude of the model is just about
exactly where Chris's picture places it, and the rotation and
attitude looks right too.

Just FYI

Thanks Sundog and, of course, El Christou. I simply love this model.

[ElChristou]

...I could be wrong again, but see if this is what you are looking for...

... mmhuu... YES THAT IS!!!!
I think I love you, you know?

Now of course I want to know what do PrecessionRate and EquatorAscendingNode... ...because I was really far away to use those commands...
Can you tell me? (or someone else for sure because you have done more than enough )

OK, FINAL RELEASE IN A FEW HOURS!!! (Bob your new texture is coming...)

Bye, TX to all.

[ElChristou]

Yep,

You can download Final release on ML or HERE (4mo)

I would like to know if all is ok with the pdf readme on Windows/Linux.
Don't forget to visit the InfoURL, the design is quite simple for now, but I don't have time to do better...

Bye

[selden]

The pdf works fine for me under Windows, and the Addon looks great, too!

[Boux]

Hi, ELChristou,
I just checked in Linux and everything is OK
Here is a screenshot I made for fun:

[/url]

[BrainDead]

ElChristou...

Absolutely beautiful and stunningly accurate.

Many thanks for your work on this creation. I appreciated the smaller texture
too, and the PDF file - as well as everything else - works fine on my pc.

Once again THANK YOU. Many thanks also to Sundog for the SSC data. I
was thinking that you wanted an XYZ file to show the precise orbit of the
model, not its attitude and positioning. Sorry...

Truly beautiful though, and well worth the wait.

Thanks once again. I love this historic replica.

Take care, Bob

[bh]

Great work Chris...my install of Celestia with cmod is on the way!
I know I'll ****it up as usual!

[ANDREA]

Yep, You can download Final release on ML or HERE (4mo)
I would like to know if all is ok with the pdf readme on Windows/Linux.
Don't forget to visit the InfoURL, the design is quite simple for now, but I don't have time to do better... Bye

Hello Chris, incredible, astonishing, real like real Liberty Bell, etc etc.
Well done, my friend!
Cannot wait to see the Vostok final release.
Bye and lots of "thank you"!

Andrea

[ElChristou]

Tx guys you are all welcome...

Next stop Vostok 1

Bye

[sundog]

I think I love you, you know?

heh Well, I love your models so I'm happy to assist.

Now of course I want to know what do PrecessionRate and EquatorAscendingNode... ...because I was really far away to use those commands...
Can you tell me? (or someone else for sure because you have done more than enough )

I was hoping someone with more knowledge than me would respond... oh well, I'm not very good at explaining things but will give it a go.

Disclaimer:
I'm still learning the ssc stuff so don't take any of this as 'fact', it's just my understanding of it so far.


When using the LongLat commands, the model will adopt the same rotational axis (poles) as the parent body, so LB7s rotational axis (or its North pole) should point to Polaris, the same as Earths.

It seems you have rotated LB7 90 degrees before exporting, I think it should have been 90 degrees in the opposite direction. The result of your rotation initially renders LB7 inverted (i.e. the base is pointing to Polaris). The only difference this makes is once LB7 is pointing where you want it, the rotation is retrograde. It's no big deal, but instead of rotating in your soft you can use the Orientation command. If LB7 in your soft has its nose pointing up then "Orientation [ 90 1 0 0 ]" should correct it so the nose points to Polaris in Celestia. Well that's how it worked on a test model I made in 3dsMax.


PrecessionRate:

Every day Earth rotates 360 degrees about its axis and 'almost' 1 degree around Sol. This combined rotation is automatically transferred to LB7 because it's in a (equivalent) geo-stationary orbit.

Now this is where you had problems-

As soon as you add RotationPeriod to your model, Celestia discards the rotation transferred from Earths motion. This leaves the models rotational axis (pole) constantly looking at the same point in space. So the model appears to tumble slowly backwards as Earth rotates. The ProcessionRate value of 360.98...etc approximates Earths daily rotation and keeps the model in a static position relative to Earth. So if you want rotation on your model and are using the LongLat command, adding this procession rate value is the first thing to do before pointing the model where you want.


Orientation:

This is not the command you want to use to point LB7 in the desired direction. It seems to be best used only to align the rotational axis. If you rotate the model before export then you don't need this command. (unless you rotate it the wrong way before export ).


Obliquity and EquatorAscendingNode:

By default the poles of LB7 should be the same as Earth. To change this, you tilt the axis (in degrees) using Obliquity, but this command doesn't define which way to tilt it, you define the direction of tilt (in degrees) using the EquatorAscendingNode command.

Note: the ssc I wrote for LB7 uses 260 degrees for Obliquity because the model was initially upside down. In normal practice you should not need a value higher than 180, I should have added "Orientation [ 180 1 0 0 ]" to flip the model the right way up and then the obliquity value would be 80, (260 - 180 = 80).


Summary:

Set the LongLat to desired value.
Set RotationPeriod (if required).
Set ProcessionRate 360.9856414794 (only required if RotationPeriod is used and you want the model to be static relative to Earth).
Set Obliquity value from 1 to 180 to tilt axis from North through to South.
Set EquatorAscendingNode value 0 to 360 for direction of tilt (negative numbers can also be used).


Just FYI: If you would like to try exporting LB7 'without' rotating it first, try this ssc. The result should be the same as the current release but with 'opposite' rotation. Of course I'm not asking you to update the current release, but it may help with other projects.

WARNING:
The following ssc is NOT written for the current release of Liberty Bell 7.
It is only an example for ElChristou to test. If you use it with the current release it will NOT have the correct orientation.

Code: Select all

"Liberty Bell 7" "Sol/Earth"

{
   Class         "spacecraft"
   Mesh         "lb7.cmod"
   MeshCenter      [ 0 0 0.003 ]   # for correcting any eccentric rotation.
   Orientation      [ 90 1 0 0 ]   # corrects the rotational axis (poles).
   Radius         0.003

   # approx position at 2'30" from take off before extension of periscope:
   LongLat         [ -79.8 28.3 70 ]

   RotationPeriod      0.09
   PrecessionRate      360.9856414794   # approximates Earths daily rotation.

   Obliquity      80      # axis tilt in degrees.
   EquatorAscendingNode   -25      # direction of tilt in degrees.

   Albedo         0.10

   InfoURL         "http://www.celestiamotherlode.net/creators/elchristou/HTML/LB7/"
}


Hope this helps. Let me know if there is anything that's not clear.

Thank you again for your great work!


cheers,

sundog

[ElChristou]

...I'm not very good at explaining things but...

Wrong, wrong!!!

For once I have understood immediatly! (I think Bob is not the only brain-dead here )

Many many Tx, now I won't have excuse for futur ssc...

Bye.

[BrainDead]

Absolutely beautiful and stunningly accurate.

Sorry, but with one teeny, weeny, tiny little omission...

Where's the crack?

Just in case you don't know what I'm talking about, here's the
URL...

http://www.lostspacecraft.com/work/Restoration/Restoration_25.html

Just kidding my friends, I'm adding my own version of the crack
as I get time to do it. I'm no artist or modeler though...

Thanks again.

[ElChristou]

...Where's the crack? ...

Hey, this photo is pretty cool and the model need a modif below the decal LibertyBell7 on the right (on the photo)... Seems I must do a 1.01 version
Later I think...

[BrainDead]

Seems I must do a 1.01 version
Later I think...

I'm very sorry I mentioned it now Chris... It was NOT my
intention to make you revise the model. <sigh> It's just that I
personally wanted this model to be as realistic as possible.

It brings back a lot of memories to this old Brain-Dead Geezer.

Take care.

[ElChristou]

...I'm very sorry I mentioned it now Chris... It was NOT my
intention to make you revise the model. <sigh> It's just that I
personally wanted this model to be as realistic as possible.

It brings back a lot of memories to this old Brain-Dead Geezer.

No, it's not a problem, but I will do that a bit later, after Vostok and the shuttle and... well a bit later...

Bye

[Vincent]

This is a great addon ElChristou !

But I have a problem : with the basic and multitexture modes, the model looks OK.


But with the OpenGL Vertex program and OpenGL Vertex/Nvidia Combiners modes, the model looks like "Emissive true" was enabled, i.e, there are no more shadows and the model looks illuminated, even with Ambient Light turned off.


I think it has something to do with Dollan and Selden's posts about Cham's 2001 space station model : http://celestiaproject.net/forum/viewtopic.php?t=8026&start=13

configuration : Win XP / GeForce 4 MX 440 SE

[ElChristou]

...But with the OpenGL Vertex program and OpenGL Vertex/Nvidia Combiners modes, the model looks like "Emissive true" was enabled...

Pas cool du tout ?§a...

I suppose this must be an OpenGL bug, because I really don't see how a 3D model can be resposable of this...
I cannot reproduce the effect on my config, I'm wondering if this is not a Windows/Celestia problem...

Sorry, I cannot help on this unfortunatly... we will have to wait for Chris for a response to this bug...

Bye