component orientation flippedAnswered
Im working on a reconstruction for a few days on and off now. Everytime I go back to my desk and try to align again the whole component gets flipped on the Y axis for no reason.
Usually I would export my imagelist and control points and start from scratch again which is by far not ideal. But since this happened a few times already I would love to go to the bottom of this now.
This what I did so far until the point it breaks:
- imported my lidar files and set Absolute Pose to "fixed" and run a alignment which turns out oriented correctly and kept this component for later comparison
- set the lidar files Lock Pose For Continue = True
- added bulks of images and re-run alignment which was fine in terms of orientation until I ran into alignment issues
- deleted the last component, added control points and re-run the alignment to fix alignment issues, saved new version file
- repeted the last two steps until I shut down my PC
- get back to my PC opened the last RC file and every following component will be flipped
This is what I tried to fix the orientation but with no success:
- delete the cache folder
- delete some of my previous alignments and re-run the alignment
- turned off several control points
- set the lidar files Lock Pose For Continue = False
- deleted all components, cleared cache and re-run just the lidar files but still turns out flipped, which is odd because they have a locked posed
- reset the view
- I compared a few control points from the lidar component and the last messed up component and the last working component are pretty close. Interesting is that the CPs despite having pretty much the same numeric values, are visually somewhere else in the 3D view because of the flip.
Some bits I want to mention:
- if I compare the position of my Lidar-Only-Component with any other which also has images, it seems that the position in the 3D view is shifting slightly which doesnt make much sense to me because the lidar files are locked.
- some of my control points are still with a yellow triangle because these are the areas I am trying to glue together. to all previous component this didnt seem to be an issue.
Some question which might or might not have to do with this issue:
1. Why does it flip in the first place?
2. How is it even possble that the component is flipped when the control points end up at pretty much the same position in terms of numeric values?
Xeon 2665 2x8Core 2.4Ghz
GTX 1080ti 11Gb
RC cache: 2TB SSD (970GB free)
systen: 500GB SSD (180GB free)
I've never experienced anything like this, although I only rarely use lidar in combination with photos.
This seems quite buggy to me.
The only thing I can contribute is that the visual representation in 3D, including the grid, have nothing to do with the coordinates in real space and will change arbitrarily. So I guess the bug is somewhere in the display area.
I think there is a feature request somewhere from years ago - or at least some discussion - but so far nothing has changed afaik.
Flipping of the scene can be caused by wrong placement of control points.
Is your laser scan georeferenced ?
Does the scene flips when you set prior pose - absolute pose to - position ?
let me comment to your suggestions
''Flipping of the scene can be caused by wrong placement of control points.''
As above mentioned I already tried turning all control points off, but the alignment still turns out upside down.
"Is your laser scan georeferenced ?"
I am not 100% sure if we mean the same when we talk about georeferenced but every single lidar scan has a unique position in space. This point dont refer to an acutal position on earth but they are aligned to each other.
"Does the scene flips when you set prior pose - absolute pose to - position ?"
Setting the prior pose to position actually helps.
Setting the lidar prior = position, which according to the manual will tell RC that the position is an approximation, will defeat the whole point of importing a set of lidar which are carefully aligned to each other right? Or in other words: doesnt it break the relationship of the lidar within itself?
At the moment I am using my lidars as a base-truth. I am having indoor DSLR, outdoor DSLR and Drone images which are all aligned in a seperate component alongside with some of the lidars. My thinking was having a set of Lidar which covers indoor and outdoor will help glueing everything together and avoids errors. Setting my lidars now to prior pose = position, kind of defeats the main idea I was after. Please correct me if I am wrong on this.
All of this leads me to a few more questions:
1. Why does RC sets the orientation correctly when changing the priors to position even though it worked a plenty of times before?
2. Is there a way to see the position of a lidar after alignment? I can just see the prior position but not the final position in space.
I just noticed that my post was set to answered. I kind of still think that there are some open questions here and would love to truly understand the problem why my components flip. Sorry if I come across pushy.
I think the Answered symbol is semi or filly automated.
I've been trying to make this point many times but unfortunately to no avail... :-(
And you didn't come across as pushy imho. :-)
Please apologize my late reply.
Yes you are right, if you want to keep absolute position of your laser scan you have to set prior pose to locked.
When you changed priors to position your laser scans were recalculated along with the images and control points and that why result was "correct". This tells us that something is wrong with overall coordinates in your project.
There can be few things happening:
1.Does your images have coordinates (gps data) please check if they are switched on, as this may interfere.
2. Please check in project settings if coordinate system is set to local or one that you intend to use?
3. On the print screen that you posted before of flipped component properties Absolute coordinates are listed - Undefined. there should be - Local or coordinates system that you use for your project.
Please try to export your project - does the result is flipped to ? If not then this is a display issue as Götz mentioned.
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