SkyTrak Reproducible Misreads Making TGC 2019 Society Tours Unplayable?

[hankydysplasia]

Let me start by saying I have a lot of fun with the SkyTrak - using it daily since Christmas. I enjoy playing with family or the kids. However, I having a hard time believing it can be functional for competitive play.

I know about GungHoGolf's tips. The unit is 0 degrees level in both axes. It is on a flat surface off the mat. My ball is placed appropriately from the laser with drivers back and wedges up. I have a new ball every couple rounds with the logo facing the sensor. Alignment works great and is accurate. I have TGC settings optimized with straight putt, no boosts. When I hit shots in or out of doors, I know where the ball is going within a 5 yard radius in distance and direction 90% of the time. I trust the device on the other 10%. I don't know my swing speed, but my driver ball speed is up to 165 on a good drive. I have a natural draw, and my misses are big hooks or weak push blocks that go shorter. My peak IRL handicap was about a +3 in 2005.

The reproducible problem is with my mid irons. I first noticed it on the Torrey Pines tournament, the 8th hole my 7 iron went 235 yards and they informed me from data on the Discord that it was a misread on the backspin. Unfortunately, at Pebble Beach this week, this happened more 7 irons than not as 3 of the 4 par 3's were 7i distance for me. (FWIW, the 7i is a newish club and clean.) Here is #17 in the first round, which was the epitome of 7i for me that was about 5 feet from intended target:

BS

HA

LA

SA

SS

BS

CA

127.1

1.1

17.5

-3.3

-370

6418

173.48

Here are all the other "correct" 7i's from the round.

128.2

3.9

18.5

-4.9

-581

6781

170.10

128.8

1.3

17.3

-5.7

-627

6288

176.41

129.5

1.3

16.7

-5.7

-626

6278

178.00

Here are a the 7i's that misread.

Hole PAR	1 4	2 5	3 4	4 4	5 3	6 5	7 3	8 4	9 4	10 4	11 4	12 3	13 4	14 5	15 4	16 4	17 3	18 5	72
ROUND 1	4	3	5	4	7	6	3	4	4	3	3	3	4	4	3	4	2	6	72

#3 - second shot from "heavy rough". Out of bounds, cost 2 shots.

131.8

4.9

17.3

7.4

616

4743

195.87

#5 - Shoots of to the right down the cliff, cost at least 2 shots (quad bogey)

131.2

4.3

17.5

-2.5

-216

4962

193.59

#12 - Long slice leaving 40 years back to the hole, saved par.

132.3

1.2

16.0

24.6

1586

3465

207.14

Again, the ball came of the clubhead the same as the "correct" shot. The ball flight is one that I have never once seen of my club in real life and I never have hit that club ~200 yards carry. This is a round where I had 5 birdies and an eagle and was hitting extremely consistently. I shot even par with 5 balls (3 from misreads, 2 due to taking an aggressive line) that had to be rehit. I'm confident that the ball flight was not how the ball was struck in each of these cases.

The second round these were my 7i's:
#12 - Deja vu from round 1. Same spot. Not as lucky and got bogey.

130.3

1.2

16.1

7.4

567

4368

195.18

#17 - Birdied first round, put same swing second round and went 30 yards past.

135.8

0.0

16.1

2.5

218

4995

202.01

And here are 2 driver misreads for good measure
Baseline "normal" drive -

162.5

1.9

11.9

-1.6

-89

3193

270.88

#6 - went into the water with 314y carry - cost 2 shots

176.9

4.9

12.8

3.1

112

2080

314.04

#9 - went 340y in game in fairway on flat but I didn't capitalize on it.

182.1

0.0

11.4

1.6

81

2915

311.51

It is not physically possible for me to hit the ball that hard.

All-in-all, with Guest (probably rightfully) shutting off rewinds, I don't really have the ability to be competitive. Assuming I don't make a single birdie with those swings, it's 9 shots, or the difference between T19 and 4th. At least 8 misreads in 2 rounds. I know it's just internet points, but part of the fun is competing and instead I finish a round frustrated.

The SkyTrak seems to be reading too much ball speed and not enough spin. It also seems to be converting backspin to sidespin. The users that reviewed the shot data on discord suggested that this was a known high speed swing data problem. I'm looking for any recommendations or options. Since this is reproducible, I would think that it could be fixed.

[hankydysplasia]

Hi hankysyplasia,

I assume you have not had any updates on this. Just to confirm, these reads happen in both TGC2019 and in Skytrak range?

I played real golf this summer and haven't played TGC since spring. (First year after having a simulator, and actually came away with several rounds under par for the first time in more than a decade.)
Started back up with the wizardofcoz league yesterday. Had a misread 6i that was around 3200 rpm and a good 7i, so still happening. Honestly don't use the skytrak range software much.

If they're doubling at that launch angle as well, maybe its a camera blind spot. No idea why it would do that.

Thanks for keeping up on this. Glad to see someone cares in investigating it. Skytrak has continued to ignore emails.

[Morini]

In the facebook group, frequent GSF poster Mirek said that he had the same problem, and identified the FMJ as a cause.

I have always felt that FMJ can cause issues. This makes a lot of sense. In order to get reads over a wider range of launch angles, I think the unit has an algorithm that can read partially captured balls. This would typically be the case for very low (going below field of view of first imager) and also very high (going above field of view of second imager). I wonder if for some reason 20 degrees in an FMJ somehow causes a blind spot of sorts, partially obscuring the ball for either of the imagers.

If the unit does attempt to read partially obscured balls, there could be a situations where there are two possible ball rotations due to the limited overlap of ball markings between images. If so, it is possible that that the system uses ball speed for disambiguation. Or maybe it merely calculates/guesses at spin if it can't find overlap. That is not as far fetched as it sounds ... the R10 does a decent job guessing spin for ALL shots. It does have the benefit of measured club head speed of course.

Hanky, you may want to try without the FMJ to see if the error persists. There will be a small risk of course. I have never hit the unit in tens of thousands of shots, but it is greater than zero.

Seth himself said that he had similar ball speeds, but who knows, maybe seth doesn't use FMJ ... because the risk is low, and it saves him time, and of course, the repair shop isn't far away.

[Morini]

I should add that I don't own an FMJ, but it would be interesting to hold an alignment rod or similar at a 20 degree angle from the red ball placement dot to check whether the FMJ cut-outs cause problems at that angle.

Since the timing between the strobes is fixed (4.12 milliseconds), the horizontal ball position relative to imager is unique (and fixed) for a given ball speed... which would explain why some ball speeds trigger this bug more than others.

For example, for every single 130 mph 20 degree shot, the ball is in a specific position relative to imager. Only at that speed and that trajectory will it be found exactly there (within laser curtain margin of error). This would totally explain it.

[Morini]

Hankydisplasia, if you happen to see this, please try with case off. There is more and more anecdotal evidence that specific ball speed and trajectory combinations causes either high or low spin. The FMJ could definitely be the cause of that. Easy test.

[Morini]

Nevermind. It is not the FMJ. I am now getting the same bug, almost exactly like Hankydisplasia. It makes TGC2019 very difficult to enjoy, because it is a common distance on the courses we play. And we can probably rule out the FMJ, because I don't use one, and still have the issue.

[Morini]

Any news or updates on this. It is most certainly a thing. My son can't use 7 iron on TGC2019 any longer, or he will sail the green by 20 yards most of the time. There is something special about this combination. I am guessing that this exact ball speed & trajectory combo puts the ball in a blind spot of some sort. But partially ball imaged ball usually results in random whacked HLA, but this bug only affects total spin, so maybe it is something else, like flawed logic in the image engine. I hope it is because then there is hope it can be fixed.

If you don't know what I am talking about, check out the TXG video with the skytrak. Halved or quartered spin for 7 iron time and time again. Made skytrak look much worse than it is. This bug only shows up for people with tour speed or higher, which is probably less than 5% of Skytrak owners.

[ProTee Max]

Any news or updates on this. It is most certainly a thing. My son can't use 7 iron on TGC2019 any longer, or he will sail the green by 20 yards most of the time. There is something special about this combination. I am guessing that this exact ball speed & trajectory combo puts the ball in a blind spot of some sort. But partially ball imaged ball usually results in random whacked HLA, but this bug only affects total spin, so maybe it is something else, like flawed logic in the image engine. I hope it is because then there is hope it can be fixed.

If you don't know what I am talking about, check out the TXG video with the skytrak. Halved or quartered spin for 7 iron time and time again. Made skytrak look much worse than it is. This bug only shows up for people with tour speed or higher, which is probably less than 5% of Skytrak owners.

Hi Morini,

Could you have a try playing with the " High BackSpin Correction" turned OFF in the SkyTrak TGC Settings?
Open the txt file and change it to OFF; Save the file and restart the computer.


Thank you

[Morini]

Could you have a try playing with the " High BackSpin Correction" turned OFF in the SkyTrak TGC Settings?
Open the txt file and change it to OFF; Save the file and restart the computer.

Thanks, I will give it a shot ... but I don't think it is TGC2019 specific, and exists for Skytrak range as well. It is just that it is much more frustrating to sail a green in a sim than on Skytrak range.

[Morini]

Well almost 3 years on since Hankydisplasia and myself posted about it, it appears to fix is in. 4.4.6 has the following:

• Fixed High-Speed 7/8 Iron Spin Bug

I believe Hankydisplasia has long since moved on, and my son is off to college. I don't hit fast enough to trigger this issue so I can't test it. I hope the small percentage of Skytrak OG users with 130+ ball speed 7 iron sim golfers will appreciate having this bug finally squashed.

TXG should re-visit their review, but given that the OG is now in death spiral, I doubt they will bother. Here is a link the the review where this issue is glaringly obvious:

https://www.youtube.com/watch?v=17ICvO80dFQ

[hankydysplasia]

I believe Hankydisplasia has long since moved on, and my son is off to college. I don't hit fast enough to trigger this issue so I can't test it. I hope the small percentage of Skytrak OG users with 130+ ball speed 7 iron sim golfers will appreciate having this bug finally squashed.

I have played about 6-8 rounds since this, and have not had a single misread with my 7 iron. This seems to have worked! I'm still on the OG Skytrak.

[Morini]

That is great news. Your diligence got the ball rolling. I don't think they ever acknowledged it. Did Rodgeric ever get back to you? We will probably never know, but I wonder what the cause is. I am curious whether there are "blindspots" in the images and if the fix simply used logic as a kludge ... basically override results when these ball speeds and VLA show up. Or maybe the images were fine, and there was a small window where the image engine had a flaw that could be easily fixed.

I am also curious to what degree Skytrak spin calculations rely on calculations vs measurment. I had always assumed 100% the latter, but maybe it relies at least in part on (very good) guessing.

I also wonder if the opposite issue is also fixed ... or maybe more common now. The one where high slow drives get tripled spin.