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Re: Space Shuttle

Postby wlbragg » Thu Oct 22, 2015 1:50 am

Thorsten wrote in Wed Oct 21, 2015 7:35 am:I've spent an hour comparing a photograph of Atlantis on the ground with screenshots, and I needed a z-offset in gear position to make the outlines match - ideally I'd like the main gear even a bit lower.

Do you have an exact number yet?

LATE EDIT:
japreja wrote in Wed Oct 21, 2015 9:28 am:Another thing, the file LandingGears in the artwork folder has the main gear bay along with the all 3 gears. It might be possible to just delete the main gear bay and replace it with the former one. you could pull it into the shuttle_02.blend using append and weld some vertices to connect it back to the heat shield.

But looking at shuttle_02.blend the gear bay looks fine. .

It was fine in the huttle_02.blend so I just hid the bay in LandingGears.

japreja wrote in Wed Oct 21, 2015 8:49 am:Just to note, only the tires and rims were made smaller to fit inside without coming through the wing.

I really wish we could get these back to spec, they have always looked proportionally small to me. Thus a refactor to the wing and/or fuselage.

japreja wrote in Wed Oct 21, 2015 8:49 am:I made the landing gear to have a suspension, the shocks can travel 3 inches down and 5 inches up from its static position when it is fully deployed, a total of 8 inches. That is what the design drawings called for in the 70's. But since the nose looked too close to the ground, I believe someone pushed up the entire gear when the shock should have just been compressed slightly in the animation. I think Shock, ShockR, and ShockL are all that need to be adjusted.

If you adjust the height of the gears in the 3D mesh, it will most likely poke through the wing again, so any shock adjustment should be done in the animation if at all possible.


I believe someone pushed up the entire gear when the shock should have just been compressed slightly in the animation

So at rest then this is being compressed too much?
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Re: Space Shuttle

Postby japreja » Fri Oct 23, 2015 5:54 am

I really wish we could get these back to spec, they have always looked proportionally small to me. Thus a refactor to the wing and/or fuselage.

The Shuttle exterior would need to be remade from scratch because of the triangulation in the mesh. There is not really an easy way to make the wing thicker. That's why I settled on scaling down the wheels. If they are scaled up, back to the size they should be, no matter what position you move anything on the gear, it will poke through the wing or heatshield. I modeled everything from the base point of the trunion fitting as per documentation.

I retrieved my downloads from NTRS and SEDS and various NASA websites that I gathered info for rebuilding the shuttle from scratch. All design documents use inch measurements in all their X, Y, Z axis callouts. A majority of the blueprints need to be edited and clarified but you are welcome to them. This would take quite a bit of time and a team, even then it would still take more than a year to rebuild it to specs.

Here are some design files you can pick through, I just uploaded the rebuilt drawing of the Main Gear along with the original. Most found in 19740027168 from NTRS which is Volume III, more documentation is in the other volumes with the same title, I just pieced the foldout pages together. The wing/rudder/bodyflap is there too, but the information on the thickness of the tiles and bonding material is still MIA.

I think that info would be the best specs we can get :D but brutally complex and intimidating. I should probably create a SF.net project to just rebuild the documents to clarify the drawings and texts of these construction files.

So at rest then this is being compressed too much?

I have no clue, I just went by the design drawings above.
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Re: Space Shuttle

Postby Thorsten » Fri Oct 23, 2015 6:04 am

That's why I settled on scaling down the wheels. If they are scaled up, back to the size they should be, no matter what position you move anything on the gear, it will poke through the wing or heatshield.


You know we don't actually have to show them when they're folded? It's not like there's a cam feed accessible. We can choose to add the wheels to the gear after it has unfolded for 10% or so via select animation easily, so there's no actual need to make the folded gear fit the wings here.

Do you have an exact number yet?


I looked yesterday, but no, I can't seem to find my notes. Looking back, what I must have done is to adjust the contact point position in JSBSim to get the correct outline, compared screenshot with transparent photograph overlaid, and then after the position was correct, fiddled with the visual model. Or not - I don't see any offsets for the gear checking again...

So, sorry, I don't really recall in detail what I did. I suggest to leave the contact points as they are, which will position the fuselage correctly, and then adjust the gear model till nothing sticks out of the wing and all wheels touch the ground - that seems the only viable configuration :-)
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Re: Space Shuttle

Postby wlbragg » Fri Oct 23, 2015 6:15 am

I suggest to leave the contact points as they are, which will position the fuselage correctly, and then adjust the gear model till nothing sticks out of the wing and all wheels touch the ground

Unless I am mistaken that is where we are now. I fixed all the issues I spoke of including the gear carriage sticking out. So unless you've adjusted something since my last commit, we should be visually correct. So it sounds like you didn't save your adjusted profile? Or I didn't notice the gear weren't touching the ground.

You know we don't actually have to show them when they're folded? It's not like there's a cam feed accessible. We can choose to add the wheels to the gear after it has unfolded for 10% or so via select animation easily, so there's no actual need to make the folded gear fit the wings here.

That's a good idea, I'll work on that and see if it is viable.
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Re: Space Shuttle

Postby Thorsten » Fri Oct 23, 2015 5:25 pm

@japreja: I've finally been looking at the SPARTAN-201 today - I wonder whether this actually was carried in some cradle or so. Placing it 'as is' into the payload bay looks a bit odd - do you happen to know that?

Also, is there a way to set ambient color for the export in blender? I routinely end up down-editing ambient colors manually because otherwise things look just way too bright in space.



For those afraid to miss the point for the de-orbit burn because they fall asleep, the TIME utility page is now fully working. Now you can set an alarm, or a timer to count down. It's largely based on the count of /sim/time/elapsed-sec since that's the FG version of MET - so I'm not really sure how it deals with speed-up of time.
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Re: Space Shuttle

Postby Johan G » Fri Oct 23, 2015 7:00 pm

Thorsten wrote in Fri Oct 23, 2015 5:25 pm:It's largely based on the count of /sim/time/elapsed-sec since that's the FG version of MET - so I'm not really sure how it deals with speed-up of time.

It simply wont. It is just the time FlightGear have been running. Try instead (/sim/time/warp + /sim/time/elapsed-sec - <offset in seconds>). I think that should both allow sub-second precision and handle time speed-up. (If you have a property representing that value, make sure it is a double, not an integer. ;) )

I find time in FlightGear tricky. In particular there seem to be no floating point property directly representing the time to use in a clock. For a bit of a rant, see this post.
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Re: Space Shuttle

Postby Richard » Fri Oct 23, 2015 7:33 pm

Thorsten wrote in Fri Oct 23, 2015 5:25 pm:Also, is there a way to set ambient color for the export in blender? I routinely end up down-editing ambient colors manually because otherwise things look just way too bright in space.


In blender when you have a UV map you need to set the diffuse (etc) on the material.
Image

This seemingly simple thing took me ages to get right on the F-15 cockpit as the intensity / balance of the instruments was 'off'. In the end I used a texture for everything and either white (1.0) or grey ( 0.8 ) - and there might still be things that aren't right.
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Re: Space Shuttle

Postby japreja » Fri Oct 23, 2015 8:53 pm

I wonder whether this actually was carried in some cradle or so.

Yes, all payload was/is carried on a Pallet. I uploaded one here but each pallet is different for each payload and I couldn't fine anything on it for the SPARTAN-201. I noticed I must have uploaded one before because there is another one on my onedrive. If in doubt just use the first one linked in this post, the second link is the old one and might not be sized.

is there a way to set ambient color for the export in blender?

Yes, and I noticed by default it is set to 1.0 in Blender. It is editable in the properties tab under shading. This is the first I actualy noticed it because I never changed it in anything I've done.

Here are the settings I've been exporting at:

Diffuse (Lambert) also settings for "Oran-Nayer", "Toon", "Minnaert", and "Fresnal"
- Intensity: 0.8

Specular (Phong) also settings for "CookTorr", "Blinn", "Toon", and "Wardlso"
- Intensity: 1.0
- Hardness: 49

Shading
- Emit: 0
- Ambient: 1.0 (i'll change this to 0.2 from now on :? )
- Translucency: 0

I've noticed I've had to change the Ambient value and Specular values in ac files and will experiment with these to see the results in FG.
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Re: Space Shuttle

Postby japreja » Sat Oct 24, 2015 4:36 am

Here is one of the only photos I could find that show the SPARTAN in the payload bay. The POST Flight press release video shows the spartan pallet which had bunch of other payload. I can add the platform that the SPARTAN sits on but it might look a tad empty. The Satellite would sit quite a bit higher than I would have thought.

3:53 - 5:00 - Spartan lifted from payload bay.
6:11 - 7:11 - Spartan retrieval



The spartan looks to stick around the Shuttles orbit during its mission to be later retrieved before re-entry. I've been looking at bump-mapping to get the gold foil texture to look right, but the program I was using had a 30 day trial and i'm not paying $90 for it (CrazyBump) so I'll have to figure it out with the GIMP. So I am off to see some videos :D

Edit: found a free plugin to do the same as CrazyBump in blender and created a new topic for it.
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Re: Space Shuttle

Postby Johan G » Sat Oct 24, 2015 11:31 am

Nice to see they have a sense of humor too. :)

Regarding bump mapping the foil I think you can look at YouTube for videos on baking one from a low-poly and a high-poly (or perhaps multiresolution one) model. See also Bump and Normal Maps in the Blender 2.76 documentation.
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Re: Space Shuttle

Postby Thorsten » Sat Oct 24, 2015 2:49 pm

Okay, bringing this together turns out to be more complicated as expected... partially because I forgot some things I wanted to fix before.

I'll write a Howto for including payloads, what has to be defined where as a step by step guide and add it to the Documentation folder of the Shuttle, then you can just go ahead and do it without me messing around with models...

I guess we should aim to texture the pallet and the Spartan if we can - would look more consistent in the payload bay...
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Re: Space Shuttle

Postby Thorsten » Wed Oct 28, 2015 7:06 am

FSWeekend is approaching, and I have to get the version to present together latest on the weekend and move it to Win.

That's (unfortunately) a hard deadline, so dear collaboarators, please let me know whether someone will address by then

* the blocked view into the payload bay
* canvas HUD/ PFD which contains enough stuff to fly from cockpit view
* screen displacement

I completely understand if that is not feasible, I have a family life as well - but I need to know whether I need to start right now to rig some alternative setup (for instance, I'd just remove the glass rather than have it black) or whether it makes sense to wait.

Sorry to appear impatient - but deadline is deadline :-/
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Re: Space Shuttle

Postby Thorsten » Wed Oct 28, 2015 9:41 am

After fixing a number of quirks, it finally seems to be working...

Releasing the SPARTAN-201:

RMS arm attached:

Image

Cargo retention mechanism unlatched and satellite lifted out:

Image

"Atlantis flightdeck, this is looking good from here!"

Image

Low-z translation burn to push away (all upward firing thrusters are inhibited, we don't want to fry the payload, so we use the fact that forward and backward thrusters point 10 deg upward):

Image

And separating from the satellite:

Image

I've documented the process of what animations and offsets need to be added where to make all this work in

Documentation/Howto.AddPayload.txt

so that anyone can do it and it doesn't require my expertise any more. The effects are still quirky (lighting inside the payload bay is complicated in a forward renderer).

@japreja: If you work on the model further, please note that I haven't done anything with the blender version, I have just changed orientation, ambient and shininess in the *.ac - be sure to keep orientation otherwise it'll be all screwed up.
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Re: Space Shuttle

Postby wlbragg » Wed Oct 28, 2015 11:43 am

Thorsten wrote in Wed Oct 28, 2015 7:06 am:please let me know whether someone will address by then
* the blocked view into the payload bay

I just looked at this. It is the object spaceshutt_spstop_4. I have no idea what that was supposed to be originally, maybe a window?
If that's what that is it could be made a lot simpler. To correct it immediately I just hid it and exported the model again and the problem is gone. I don't know if we need that object, I guess if it was suppose to be a window them OK, I can remake it if we need it. I have to leave and don't have time to look at the settings until later on this morning.

This is the object causing trouble.
Image
This is with it hidden.
Image
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Re: Space Shuttle

Postby abassign » Wed Oct 28, 2015 12:51 pm

@wlbragg

The Space Shuttle is an exceptional machine, I am saddened when I see objects that graphically describe that wonderful machine with too little detailed! I know the polygon have a processing cost, but we are in 2015 and not from 2005 to 2010, the graphics cards are very much improved. For example, a few weeks ago I posted the test in a post of this forum, I have verified experimentally that it was possible to obtain a minimal reduction of performance with graphic objects composed of 500,000 vertices (about 40-50 MB of .ac file). At this point I think it is not a problem to increase the vertices, at least in the points with high visual contrast, those in which tends to pause the eye of the seer. Such as rounded corners (the portholes and windows) few dozen extra vertices can make an incredible difference, absolutely no change performance! :)

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