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Guest Patrick_Waugh

Contact Points - Starting without a crash

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Hey guy,Well, not sure what the best way to do this is, but now having completely finished the flyable model, I'm trying to make it loadable in FSX.So, for the time being, I just copied the B206 SimObject to a new SimObject, to be a base aircraft. I'll worry about getting to orbit later.Anyway, first thing was to create some contact points so I could load the ship anywhere. With the B206 contact points it would load, but, of course a large part of the model was in the ground. So, in Max I created a plane with 4 verts and located it just below the hull to then check the location of the 4 points to use as contact points.The model is in Max with 0,0,0, at a point representing the CG mid-way between the hulls. Thus, the plane was -139' down, where I then put the 4 type=3 (skid) contact points.When I load, it immediately crashes, but if I pause it I can slew up a bit and then slew it around and fly it no problem.What do I need to do to fix this?http://i91.photobucket.com/albums/k282/Ben...ionics/Mtns.jpg

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Eliminate the scrape points. They aren't needed, really... ;)In fact, you could simply put very long "legs" on this bird and eliminate the dummy plane altogether.

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>Eliminate the scrape points. They aren't needed, really...>;)There are no scrap points, only the four skid points.>In fact, you could simply put very long "legs" on this bird>and eliminate the dummy plane altogether.There is no dummy plane, I only used it to get the location of the verts to use for the "skid" points.It is the verts from that plane that I used as the location of skid points. But the model crashes on load.

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Well, I looked over the CG and vars for the sample max file, and I'm doing the same thing.So, I went back in the sim to do a more detailed look at what it was doing.When I use a standard aircraft, I can slew it up, but when I slew it back to the ground the contact points stop it, as they should.With my model, if I slew it down, it goes all the way into the ground to the CG point as if the contact points are not there.Also, turning off crash, I see that what is happening is that when I start the aircraft immediately starts to rotate (pitch) over upside down.If I slew it to just above the ground in level attitude, it will pitch forward and crash.So, while it works fine if I start from a saved flight in flight, I'm at a lose as to what is going on here.

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I have verified the placement of my "skid" points by placing lights at the same coordinates, and I tried moving the front two out in front more to see if this helped. It didn't change anything.http://i91.photobucket.com/albums/k282/Ben...onics/ATest.jpgIf I pause the sim, and change to this aircraft, then slew it up to just above the ground, it will then climb as if someone added power. Weird.As noted previously, the contact points do not prevent it from slewing into the ground to the CG either as they should.

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After lengthing them further, it now will start above the ground, so apparently FSX either paid attention to the geometry, or this is an airfile thing.So, I have experimented further, and tried using the B747 airfile. Basically, I get the same results. It now starts above ground, but will still sink past the contact points and crash.So no joy, guess it will just have to be started from in flight.I think the animated version had landing gear, but of course, that's not considered cannon. If anyone finds a picture of it though, it might be worth checking out. Of course, if I can't get contact points to work it's a mute point anyways.

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>>>>With my model, if I slew it down, it goes all the way into the ground to the CG point as if the contact points are not there.<<<>>> As noted previously, the contact points do not prevent it from slewing into the ground to the CG either as they should.<<<

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When you refer to "static_cg_height", what are you talking about?When I look at the sample model, it's zero point is half-way up the fuselage, and 1/3 of the cord back from the leading edge.My zero point is similarly placed as you can see in the pic I posted.So, not sure what you are refering to, could you be more specific?

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>>>>When you refer to "static_cg_height", what are you talking about?<<<

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>>>>>When you refer to "static_cg_height", what are you>talking about?<<<<>>It

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Your Static CG height is set to ground level "0" feet. Raise it up to where it needs to be. This example shows 5 3/4 feet.static_cg_height=5.750 //feet, altitude of CG when at rest on the groundFred

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>>>>You missed my point of the question. You said the above before, and I got that... but what does this mean in practical terms in the sim... ie how do you set it? But, I realize now you were refering to the var in the aircraft.cfg... it's zero, see below:<<<

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Ah... I was not getting that it needed to be postive (which should have been obvious from the name). I tried it with a negative amount with the same result, so I'm off to try the positive variety.thanks

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Making progress.With this:[contact_points]point.0=3, 400, 150, -139, 3000, 0, 2.5, 0.0, 0.3, 2.5, 0.60, 0.0, 0.0, 7.0, 0.0, 0.0point.1=3, -800, 150, -139, 3000, 0, 2.5, 0.0, 0.3, 2.5, 0.60, 0.0, 0.0, 7.0, 0.0, 0.0point.2=3, 400, -150, -139, 3000, 0, 2.5, 0.0, 0.3, 2.5, 0.60, 0.0, 0.0, 7.0, 0.0, 0.0point.3=3, -800, -150, -139, 3000, 0, 2.5, 0.0, 0.3, 2.5, 0.60, 0.0, 0.0, 7.0, 0.0, 0.0static_pitch = 0.0static_cg_height = 135.00It now doesn't go into the ground, but will sit momentarily before bouncing up a bit and then rolling to a crash. So, I'm attempting to widen the contact points to see if this helps.Sad that one must use contact points that are so far from the model.

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Ok, figured out that I had to super-size the MOIs. Now she won't bounce just jitter a litte.Main thing is that she won't crash immediately so you can easily move from place to place.You guys were right on the money with the static_cg_height... I thought it was the height of the CG above the zero point, but now realize it's really the distance from the CG to the ground.Now when ACES comes out with a rocket air file or warp drive, we'll be set, haha.

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