I posted previously about the difficulty making adjustments to a registered set of scans. To get a handle on how the program works, I ran an exhaustive test project. Here's is what I learned and where the obvious roadblocks to flexibility are. But first, let me say that I LOVE this product and it is miles better at processing scans than the competition's Scene software. Scene can do some things that Recap Pro cannot, but I'll bet more features are forthcoming.
My projects involve smashed up vehicles, un-smashed vehicles and the roadways where all that happened. When you are registering a room or a building, it's very easy to see if your scans are tight in the preview plan view as you keep adding scans to the registered list. When you are in the woods off of a roadside, you get poor (red) feedback from the program's statistical analysis because at least one of the three metrics isn't happy. Trees are so spacially chaotic, that scan overlap isn't great and the result may indicate poor, even though the registration is good. That's fine. To be expected. In some cases, I will never get anything but a red/poor indication yet I must except it and proceed. The only intermediate review of the scans registered thus far is a plan view, color coded cloud. It is easy to see that a room, for example, a scan dosen't line up. Not so easy to tell if a scan in the woods is rotated 10 degrees off from the ground plane (which is what I had). If there was a good way to inspect the interm cloud in full 3D, I could see potential problems. More on that later.
The workflow is generally very good. Import scans. Check. Start registration and pick a base scan. Check. You get a split screen view. Registered scans on the left, unregistered on the right. Like I said above, you get some useful feedback, but it is not always possible to tell if a newly registered scan is really acceptable and the previews are top view only, which give you limited visual feedback. So I finish registering all the scans. There were 17 scans in the project that prompted this investigation. 5 scans were aligned fine, but off from the other 12 scans, which were aligned together. The base scan was in the group of 5. It wasn't possible for me to tell that things went askew during registration. You learn the truth about your project when registration is complete and you Index. When you Launch Project and see the Indexed scans, then you see the combined point cloud in all it's glory. Rotate, move around, get a good look-see. Now you see there are problems. Then what?
I really love the Project Navigator (stacked layer icon in the lower right). The mosty useful thing there is the Scan Locations. I see some of the scans are not properly aligned. Which ones are they? Going through the list under Scan Locations and toggling the view icon makes that scan disappear from the point cloud, easily identifying which scans are out of alignment. With the 5 bad scans identified, I now want to pull them out and re-register them to the 12 that I'm keeping. That's where things get messy.
There are two ways to remove scans and one way to continue with the existing registration process. In the Project Navigator's Scan Locations, you can select the "X" for a scan and you are warned that it will be removed from the project. Gone for good. Bye, bye. You can go to the menu while in Project view and fly-out the Home icon (upper left) and select the Register icon. That takes you back to the Completed Registration view. You see the selected scan full screen and all the scans are currently registered and are listed on the left. There is NO menu at the top of the screen when you return to Registration after Indexing and Launching the project. The only way to kick the current registration into gear is to remove a scan from the registered list. Here's the gottchas with that: You cannot remove the base scan (the one at the top). I understand that the entire registered point cloud is using that scan as the relative coordinate system for the registered point cloud, so it seems obvious that that one needs to stay (more on that later). If you hover over the "X" on any of the other registered scans, you see a ghosty arrow over that scan and pointing down to the bottom most scan, indicating that all the scans from there down will be deleted. That sucks. So plucking out a scan, and only that scan, is not possible here. You might think, well it has to be that way for some reason. Ah but what about.....
When you are back in the Project Navigator's Scan Locations you can delete ANY scan, even the base scan. If you go back to the Registration View, the scans you deleted in Scan Locations are not there any more. So it was possible to pluck out any scans necessary, just not it Registration View. And true, the scans were removed from the project all together, but better that, than loose the 12 scans that are fine. I can even delete the base scan in Scan Locations and when you go to Registration View, the next scan in line is the new Base Scan. I suppose the registration coordinate system had to be re-calculated to base off the new base scan's relative coordinate space, but it happened, you just can't do it while in Registration View.
Okay, those are some inconveniences, however Scan Locations gives you good investigative feedback from a fully functional point cloud and you can remove any scan necessary. Now to re-register the removed scans. Going back to Registration View show a list of registered scans on the left, minus the removed scans. There is no way on this interface to re-import the deleted scans (no menu bar exists at the top), making them appear in a right pane and pick up registration from the currently completed registration. You can though, if you remove a scan from the registered list. Since everything below your selected scan will get removed to the Unregistered Pane, it only makes sense to remove the last scan. If the scan at the bottom happens to be one of the offending scans and you needed to remove it anyway, then great, no harm no foul. Of course it wasn't in my case. So I had to remove a prefectly fine scan from the 12 good scans just to reboot the process. Removing the last scan re-launches the registration process. The removed scan now shows up on a right pane of unregistered scans. The menu bar reappears (yea!) and you can now access an Import Files/Folders icon and re-import the scans you deleted in Scan Locations. When you do that, two things happen: it warns you that the file you selected will be overwritten, meaning even though I was warned the scan will be removed from the project, it knows it was in the project (so re-access the removed out scan then). Instead, you have to select "Okay" (yeah, right, whatever) and let it re-import the files as if from scratch. When you go to the Registration View, the imported scans, along with the one you removed to re-launch the registration, all show up in the Unregistered Panel on the right. Continue registration and hope for the best next time around. (I got all 17 tight on the second pass).
So, there is a work around, but it's obvious that all the tools are there for greater flexibility, they're just not available where it counts. These suggustions would make Registration, Indexing and Project View a rock-star of ultimate flexibility.
1. Allow any scan, and only that scan, to be removed from the registration list. If you can do it in Scan Locations, you can do it here.
2. Allow registration to continue from a completed state by assigning new scans to the unregistered list (keep the menu visible) and/or by the removal of scans as executed in #1.
Those two things would add greatly to project flexibility. The next improvements would take it to eleven:
1. Index at any time from the currently registered scans. Ignore the ones left unregistered. Who cares? I want to see the full point cloud when I want to see it.
2. If scans are removed from Scan Locations, they can show up as unregistered, thereby not requiring re-importation.
Please consider these implementations. You have a great product. These tweaks would make it very flexible.
Best regards,
Buck Wyckoff
Buckward Digital
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