On Sunday, June 26, 2011 17:27:06 xsaint wrote: > Hello All... > > I am trying to better understand how YASIM calculates its contacts > points.... > Hi there, I'll try to answer, see below:
> 1) As from my experience, the SIM crashes when some part of the wings > comes in contact with a building or ground and it does not crash if > other parts of the wings hit the ground of a building.The wing > specification is correct in FDM as checked againts the blender script. > So how does it deduce the contact points? > There might be a difference between regular collision detection provided by the FG engine itself, about which I have no information, and YASim _ground_ collision detection. The latter is implemented as follows: Contact points (internally represented as gear objects but with special properties and hardcoded values for friction) are compiled from the wingtips and the fore and aft tips of the fuselage. These contact points will hold at full compression 10 times the plane's mass. So for a conventional airplane there will be two contact points for the fuselage (nose and tail), the main wing tips, the tips of the horizontal and vertical stabiliser. Any collision detected with these contact points will be treated by YASim as a special case of gear collision and compared to the force mentioned above. > 2) Eventhough CG looks like it is in correct place, in YASIM, the plane > do sink to the ground before take off. Insufficient lift maybe.... but > the back of the fuselage do sink into the runway. As such, as > possibility of implementing tail strikes? > It is possible that either the aft end of the fuselage as defined in XML is higher than the lowest part of the model, or that the mass which it has to sustain is larger than the spring compression of the contact point can sustain. You can try to compensate the first issue by placing a fake gear object at the lowest point where the fuselage touches the ground. > Much all appreciate all valuable replies and also if you could point me > towards any valuable YASIM documents. > There is a technical document floating on the web, can't quite remember where but try to google YASim-simnotes.pdf Other than that, your best reference is the source code. Hope it helps, Adrian ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2d-c2 _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
