Flight model used by Skytrak vs sim software

[butette]

Is the flight model used in Skytrak software the same as the one used in the various simulators (TGC, PG, CG3D). The reason I asked is because when I play the CG3D one hole demo I find CG3D left/right spin even worse than Skytrak range, and carry yardage is consistently a little less as well. Just curious.

[skytrakali]

ST actually measures five things: ball speed, vertical launch angle, horizontal launch angle, spin axis and spin rate. Everything else is calculated. So I assume that TGC, PG etc. just take these 5 inputs and then work out the rest themselves using their own patented internal models. For this reason my guess (and it's only a guess) is that CG3D may indeed be giving slightly different carry yardages to ST, but the spin is the spin is the spin.

There is one rider to this. I don't know the ST (or sim) algorithm for spin axis. In general spin axis is a 3-vector. But it'd be very tempting to assume that the spin axis of a golf ball passes through the centre of the ball (even though in reality it might not). Then it's only a two-vector. It's therefore not impossible that ST and the sims interpret the ST spin data differently. A definitive answer can only be provided by the developers who know the algorithms in detail. But my guess is that you are just seeing the spin that ST measures, even in a sim.

[clark55810]

Seems to me that Seth responded in another thread that ST just provides the readings to the simulator software, but I could be wrong. I agree with the 5 measurements that ST is collecting.

[Dan McWhirter]

If you look at the patents, there's a whole lotta math going on to compute the spin and spin axis, from what seems to be two laser shot pictures of the ball's dimples and markings differential movement. Is spin and axis computed within the box or within the app? I expect it comes from the box, given that so many sim programs have integrated with SkyTrak. However, I also suppose, since all these sims are programmed to integrate with their developers' respective devices (comprising pads with led emitter/receivers and cameras or radar emitter/receivers), the sim programs may be able to receive more basic data and do their own model calculations of spin and axis, in which case there could be differences in carry distance and curvature, if all else is equal.