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Bug with saving large clouds in BIN format
Posted: Mon Aug 08, 2016 4:56 pm
by deepminder
Hello,
today I was working with large point clouds (about 1 billion points).
Point cloud was imported from PTS. And when I tried to save it in BIN format and then open in CloudCompare again, the point cloud gets "corrupted":
After opening I don't see point cloud, scale bar shows something like "2e+38"(normally scale should be 200 meters), and in "Properties" panel I see "Box dimensions: X=2e+38, Y=1.5e+35..." (Instead of X= 415 m, Y=225 m).
CloudCompare 2.8.beta (64bits)
Windows 10x64
Re: Bug with saving large clouds in BIN format
Posted: Mon Aug 08, 2016 7:12 pm
by daniel
Oh, I heard about a similar problem once! Sadly I really don't know why it happens. And it doesn't seem 100% reproducible... Can you try it again and see if you get the corrupted file again?
Re: Bug with saving large clouds in BIN format
Posted: Mon Aug 08, 2016 9:55 pm
by deepminder
I tried it today five times. With original point cloud, with transformed. With small point clouds (few millions points) everything is OK, but with big one - always problems.
Also I noticed one more thing. If I make a transformation of point cloud and save it in PTS, the resulting PTS has the same number of points but the size is different a bit (few bytes). With BIN if I save original cloud - I get corrupted cloud, and if I save transformed cloud - I get corrupted cloud of the same (byte to byte) size.
And one more thing I noticed during play with this point cloud. When I import PTS I'm asked about global shift, and I see something like (sorry, can't take screenshot now):
Original coordinates: X=46327932.123456, Y=3256713.654321, Z=7.456789
Global shift: X=-46327900.00, Y=-3256700.00, Z=0.00
Local coordinates: X=32.123456, Y=13.654321, Z=7.456789
But if manually change global shift to X=-4932790.00 I will receive in local coordinates some very huge number like X=35269885214752366588442698844266998552
Re: Bug with saving large clouds in BIN format
Posted: Tue Aug 09, 2016 6:20 pm
by daniel
Interesting. I should try to reproduce the bug on big files on my side then.
Regarding PTS files: as they are ASCII files (i.e. the numbers are written as text), the size of the file changes slightly when the numbers change. On the contrary BIN files are binary files. They use a constant number of bytes for all numbers.
And last but not least the Global Shift bug is also very weird?!