Cloud to Cloud - Register based on multiple non-planer points

[Anonymous]

It is my understanding that recap cannot cloud to cloud register from multiple non-planer points.  This is very much desired.  Leica's Cyclone does this very well.

[ryan.frenz]

What do you mean by 'non-planar'? As far as I know you can choose any 3 point pairs to manually register in ReCap.

Some more details would be helpful.

Thanks,
Ryan

[Anonymous]

That is a great question because 3 points make up a plane. Sorry for the confusion.

It is my understanding that the 3 points that you pick in recap need to be "on a plane" like a wall, table top, face is a cabinet, front of a flat door, etc. Alternative, I understand that you cannot pick the tops of three different fence posts that are at different heights; or 1. top of a pole, corner of a building, crack in the asphalt;
Or 3 different corners of different buildings or columns; things that may not represent a plane object.
But, in recap, one needs to pick 3 points on a plane shape, not arbitrary points or endpoints. It is my understanding that corners or endpoints are not acceptable in recap. Therefore the comment about "non-planer". Let me know if this helps. It if my understanding is incorrect.

Cyclone registers with common end or arbitrary points very well.

[ryan.frenz]

Ah, I understand, thank you for the clarification.

This is a misunderstanding.  ReCap doesn't care where the points are, as long as they roughly correspond to the same point in each scan ('roughly' meaning a foot or so).  The points can be corners, posts, or whatever you want.

When we train new users, we recommend that they select points on flat, even surfaces.  We say this because most users do manual registration using RealView, which renders like a panorama (aligned to the point cloud 'behind' it).  In this type of view (and on high-DPI monitors) it is very easy to 'miss' the exact point you want.  If you're clicking a flat surface, this doesn't change the actual point very much.  But if you're clicking on a corner or edge, etc, the point you get could be quite different.

One more note: ReCap only uses your point pairs as an initial hint for the registration.  Once it has the hint, it looks at the whole scan to find features that overlap with the registered group.  You really don't need to be over-precise when providing the point pairs.

-Ryan

[Anonymous]

Ryan, I picked arbitrary points yesterday in the field with the ipad pro & recap app, and it worked great.  It worked great 90% of the time, then on one scan through the registration became corrupt ... an error on in the recap pro app (on the ipad).  I don't remember the exact wording but it is the 2nd or 3rd time I have received that message.  Back in the office after transferring to the desktop recap pro app and I had 26 scans.  22 registered perfectly and 3 needed a couple manual pics to registered, and one scan seemed to be dropped.  I'm going to go back to the ipad app to see if that scan (which I know I did) is still there.  I was thrilled how well it worked inspite of the 'corrupt' error in the field.  Also, in the field I was getting high 80s and low 90s with the registration.  Back in the office, on the desktop app the registrations were hi 90s mostly and some low 90s.  

I'm very satisfied with the registration in the office.  Not as much on the ipad.  Knowing that I can pick arbitrary common points it great.

[ryan.frenz]

Interesting.  You really shouldn't get different results on the iPad vs. Desktop, in general.  It's possible the discrepancy you saw was related to the corrupt scan you encountered.  If you can provide any more info on that, or see it again, let us know.

Please feel free to use the forum for further questions.

Thanks,

-Ryan