While scanning something on the turntable this evening, I got an error (can't write to file). No big deal just cancel and re-try. It worked, with a catch - the turntable lost it's 0 point.
My understanding of it's performance so far is that whatever position it's in when calibrated, that becomes 0° of rotation. If you have more than 1 scan, the selected rotation distance is divided by the number of scans which are divided equally in either direction of the 0, IE if you want to make 5 scans over 180°, you will get one at the position the turntable is in "at rest" and 2 equally spaced on either side of that.
In my case, it had rotated into position to take the first picture at the furthest point (say +90°), came up with the write error but then failed to return to 0. From that point on, everything was 90° out. Now I'm lazy and didn't want to go through the whole card calibration process again so I pushed forward. But what you can't do is define the start and end of the sweep. For example, if you want a 190° sweep, you will get a sweep from 265° to 95° and there's no means to make that 95° to 190°.
I might be over-thinking the whole thing, but it would be nice, in a case like this and I imagine in other scenarios, where you want multiple scans but away from the range that includes the at-rest point. It would be nice to have a little gauge or text box that indicates where in it's rotation it believes it is too.
Hey Andrew,
Thanks for the insight and request.
First, let me say that the turntable error is common and due to a problem on the actual silicon on the processor. We found a fix and are working to get it implemented. Hang tight, thank you, and apologies, we’ll fix this soon.
One other small piece of info, is when the turntable gets an error, it will lose its global position, as you've discovered. However this shouldn't affect calibration. Calibration only determines where the turntable is with respect to the cameras, not its rotation.
Finally getting to your actual request:
The turntable gets its zero position on reset. This can be via software after an error, or just simply when plugging in the turntable. The manual rotate buttons on the scan settings screen should let you set the center position of the scan before the scan starts. However there is currently a bug that doesn’t respect this, that we’re fixing right now. This will be available in the next patch. In the meantime, to get around this simply rotate your turntable with these buttons to where you want it to be centered, then unplug and plug your turntable, then press Scan. Calibration should be saved. If not please let us know.
@Drew Shark Thanks, Andrew and Drew.
Great question and very helpful reply!
Thanks @Drew Shark, that's helpful information. I was part way to success using the buttons to rotate it to what I thought would be a new 0 but it immediately spin 90° upon scanning. Not sure why it didn't cross my mind to unplug it.
On that note, would it be possible for a user to build an externally-powered, larger (both diameter and weight capacity) turntable that the THREE could still operate? I suppose the question really is "how much support is available to users wanting to interface with the turntable port?"
