Andrew Bailey (andrew++at++csunb0.leeds.ac.uk)
Tue, 08 Jun 1999 18:12:09 +0000
Thanks for the reply Angus.
You mentioned that I could simply attach the same DCS under each of the SCS'
defining the wheels. This is what I originally wanted to do! However when I
translate the wheels in MultiGen the translations all get flattened in the
OpenFlight loader. I know the flattening phase can be turned off, but it
seems a bit over the top to forgo all the other flattening for the sake of a
few transformations.
I have also tried looking at the OpenFlight loader itself, as the SCS' can be
grabbed before they get flattened, as Performer loads the database. However,
I am still left with four flattened wheels and the transformation from the
origin for each wheel.
I can get the wheels moving using 4 DegreeOfFreedom nodes in MultiGen (which
get translated into pfDCS') but this is really a waste. Any help would be
much appreciated.
thanks,
Andrew
Angus Dorbie wrote:
> It is obvious that any instance of an object must have some unique
> transformation above it in the graph to displace it from the other
> instances. So, at the very least each wheel will require a unique
> translation to the correct position on the vehicle.
>
> The only remaining question is do you rotate the wheels as part of the
> 'instance', or do you rotate them as part of the translation. Currently
> you do the latter and that means that to rotate the wheels you must
> modify 4 matrices.
>
> To have 1 matrix for rotation just make the translates for the wheels in
> four SCS' and add the same DCS->wheel as a child to each SCS.
>
> Cheers,Angus.
>
> Andrew Bailey wrote:
> >
> > Hi,
> >
> > I have modelled a car in MultiGen and have nearly got the wheels
> > rotating. Originally the wheels were all just raw geometry, so the
> > centre of rotation was not at the centre of each wheel, hence when the
> > DCS for the wheels was altered the 4 wheels rotated about the origin,
> > not about the wheel centre (generating some very humorous results!).
> >
> > What I would like to do is model the wheels as multiple instances of a
> > wheel modelled at the origin, so that I can just apply the rotation to
> > that wheel and the instances will all rotate as well. This should
> > eliminate the need to move the centre of rotation for the DCS each time.
> > I do not think this is possible though. Can the loader for MultiGen
> > flight files correctly interpret instanced beads?
> >
> > I have tried this approach, by having one wheel at the centre of the car
> > model rotating accurately, however the instances are stationary, or
> > still rotating about the wrong point. I do not really want to have to
> > move the centre of rotation for each wheel.
> >
> > Any ideas?
> > thanks,
> > Andrew
>
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