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Project Apollo - NASSP 6.4.3 released!
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| | |-+  Collision detection and all that come with it
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Author Topic: Collision detection and all that come with it  (Read 17754 times)
FordPrefect
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« Reply #30 on: June 16, 2009, 03:46:30 PM »

Theoretically, it should fix the jumping on LRV, but only FordPrefect can confirm that, it seems.

I'd love to tell the problem is gone, however it looks it is still there.

http://www.youtube.com/watch?v=6RlhQd9voPk

I have no idea what is causing it. I have 60 FPS locked without and 25 FPS while recording the action with Fraps. I'd say about 70 percent of the time, the LRV is stable, but then after some time it starts to jump again. I have the feeling it depends on certain locations of the surface mesh. I first thought it is related to Taurus-Littrow mesh itself, because the valley floor actually incorporates two similar meshes, spaced apart by a tiny amount of vertical separation. This is in order to have the upper mesh half transparent with a cratered looking "microtexture" above the large texture mesh, to provide more detail up-close. However, the exact same jumping occurs at the Fra Mauro mesh as well.
Hmm... could my system specs have any relevance to this?
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My Project Apollo work in progress:
* New detailed Lunar Module Ascent stage with virtual cockpit (VC currently planned as eye candy only) 18 % done

My Project Apollo work to be continued:
* new Service Module SPS engine bell
* various Saturn V textures, exhaust textures
* SIM Bay for the SM


My long-term plans are to create a:
* New detailed Lunar Module descent stage (eventually models of all flown LM's)
* New F-1 engines for the S-1C stage showing the foil (batting) insulation
* New LUT and launch pad (if nobody else does it)
bluespace88
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« Reply #31 on: June 16, 2009, 04:06:02 PM »

so it jumps even at 60fps?
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Artlav
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« Reply #32 on: June 16, 2009, 04:09:18 PM »

Thank you, that is a significantly better description of a problem - the jumping is between an elevated area and the sphere - part makes it a different domain to look into.

Will there be any difference (jumping-wise) if you set tilting=0 in collision.cfg?

Is there any FPS dependency? Like, recording on 25 FPS and non-recording 60 FPS?

Does it happen with LEVA?

Is there anything special about the terrain jumping happens on, in Fra Mauro case?

Do the two meshes lay in separate files? You can remove one from the collision cfg then.
Shouldn't do any problems, but the performance will be reduced with two.

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FordPrefect
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« Reply #33 on: June 16, 2009, 05:02:12 PM »

so it jumps even at 60fps?


Is there any FPS dependency? Like, recording on 25 FPS and non-recording 60 FPS?

No, the jumping happens at 60 FPS as well as 25 FPS (and essentially the whole varying range between the two FPS numbers)


Will there be any difference (jumping-wise) if you set tilting=0 in collision.cfg?

Yes, no jumping at all with tilting=0 !


Does it happen with LEVA?

No, not at all.

Is there anything special about the terrain jumping happens on, in Fra Mauro case?

It looks like the LRV starts jumping when driven on the large Fra Mauro mesh (to the northeast of the LEM, where the terrian rises to the big crater). Also maybe worth mentioning, if I use 10x time accel, the LRV seems to be jumping a lot less than in 1x accel.


Do the two meshes lay in separate files? You can remove one from the collision cfg then.
Shouldn't do any problems, but the performance will be reduced with two.

No, it's a single mesh file. Artlav, I have another idea. Maybe the bug is dependent on the mesh density? I mean, it looks like the jumping happens at places with a less dense vertice distribution on the surface mesh. I'll have a look at the mesh in wireframe mode to see if there's any coherence.
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My Project Apollo work in progress:
* New detailed Lunar Module Ascent stage with virtual cockpit (VC currently planned as eye candy only) 18 % done

My Project Apollo work to be continued:
* new Service Module SPS engine bell
* various Saturn V textures, exhaust textures
* SIM Bay for the SM


My long-term plans are to create a:
* New detailed Lunar Module descent stage (eventually models of all flown LM's)
* New F-1 engines for the S-1C stage showing the foil (batting) insulation
* New LUT and launch pad (if nobody else does it)
Tschachim
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« Reply #34 on: June 17, 2009, 08:12:52 AM »

I did some more tests driving towards cone crater and now I basically can confirm the jumping FordPerfect reported. It's only the LRV and only at some places, it looks like in FordPerfect's video, the LRV is shortly jumping below the mesh. I tried to do a screenshot, the camera position here is slightly below the surface mesh.

Also when driving on a slope, the driving direction seems to change too much and a little bit weird. Sorry for the poor description, but I'm heavily distracted by the recent Virtual AGC stuff, so FordPerfect, please keep up your testing, it looks like it's more helpful than mine at the moment...

Cheers
Tschachim


* 2009-06-17_150439.jpg (29.65 KB, 901x689 - viewed 416 times.)
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Artlav
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« Reply #35 on: June 17, 2009, 10:56:39 AM »

Got it. It jumps nicely here at 0.1x.
Investigating already...
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Swatch
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« Reply #36 on: July 06, 2009, 08:51:06 AM »


Quote from: Tschachim
No. I need to do more testing later, it looks like the touchdown points need some improvement
Three-point model makes it look weird, same for LM. I think i can get more than 3 points support working soon.

I'm going to do more tests tonight, but besides the "3 points problem" making the rover behave kinda like a tricycle it seems to be stable, no crashes, no jumping.

If we really wanted to be fancy, I can imagine a way around this.   I was thinking and it occurred to me, we could make each wheel its own object and then make the chassis another object.  We could then 'attach' the wheels to the chassis using Orbiter's attach points.  Using Orbiter's AddForce we could make the LRV act more like a buggy with bouncing wheels etc.... I could go on, but I know this is much too complicated to implement.

Maybe what orbiter really needs is a new feature....   SPRING ATTACHMENT!  This actually could be very useful for Orbiter.  Theoretically a tether could be realistically simulated, as well as some other interesting behaviors... and we could use it to make a suspension for the rover! Happy
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My Project Apollo Work:
CM Visual
 -VC (~75% complete: texture work beginning again; mesh-78%; texture-70%)
Propulsion Particle Improvements (Focused on S1B right now, BETA 1.0 has been commited)
New Docking Method (~50% complete: research complete; coding partially completed, testing not underway)

Future Work:  (if it's here, it's deemed unnecessary to upcoming release)

Older Work:  (if it's here, it's fair game to whoever wants to improve)
EMS Implementation (committed: minor flaws, but groundwork is there, needs extensive testing)
EMS scrolls (committed: not refined, but usable)
SM Visual (committed: mesh-finished, texture-60%; possibly revisited in future)
J2 Texture (commited: room for improvement)
LRV (committed: mesh-finished, texture-90%; in future a ground up rebuild may be in order, but not on my plans)
Tschachim
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« Reply #37 on: September 19, 2010, 09:45:28 AM »

As already mentioned here: http://www.orbiter-forum.com/showpost.php?p=203405&postcount=282, CollisionSDK is not working with Orbiter 2010-P1, CTD in collision.dll directly before the simulation would start after loading of the scenario is done.  Sigh

I hope this can be fixed easily, perhaps a rebuild with the new OrbiterSDK is enough?

Cheers
Tschachim 
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