Global shift/scale adjustment

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abrownperth
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Joined: Thu Jan 25, 2018 1:41 am

Global shift/scale adjustment

Post by abrownperth »

Hello,

I was hoping it would be possible to as a stop gap measure add the ability to override the import so it always uses the previous input without flashing up the warning "Warning: previously used shift and/or scale don't seem adapted to this entity". This slows down the import process when dealing with point clouds that span a large area.
global shift2.PNG
global shift2.PNG (30.32 KiB) Viewed 10112 times
Would it be beneficial to run the global shift/scale adjustment at the end of importing all your files so that the global shift used it optimized for all of the files not just the first file loaded in?

kind regards,

Andrew
daniel
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Re: Global shift/scale adjustment

Post by daniel »

Hum, that would kill a bit the purpose of this warning... Another way to do that, if you know what you are doing and measure the consequences, is to change the thresholds for this warning to appear (via 'File > Global Shift settings'). I would recommend only changing them while you are importing clouds from large areas, and then turning them back to their default parameters.

And sadly, no, we can't wait to apply this shift, as the whole purpose is to store the coordinates in twice as less memory (32 bits instead of 64 bits). Waiting for all the points to be loaded to then compress them in memory would be too late.
Daniel, CloudCompare admin
abrownperth
Posts: 6
Joined: Thu Jan 25, 2018 1:41 am

Re: Global shift/scale adjustment

Post by abrownperth »

Hi Daniel,

cheers for the tip. i had played with adjusting the threshold by an order of magnitude.

Okay that makes sense as to why it couldn't be done after loading the data in. However what if we approached it differently?

Cloud compare clearly checks the file it loads and determines the minimum and maximum X,Y,Z values before suggesting a shift. Would it be possible to have cloud compare check all of the datasets to find the maximum and minimum X and Y values of the full dataset before then recommending a shift to use when importing the data?
daniel
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Joined: Wed Oct 13, 2010 7:34 am
Location: Grenoble, France
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Re: Global shift/scale adjustment

Post by daniel »

Ah ah, no, CloudCompare only deduces the shift from the first point. It would be very long to read the whole file once (without storing the data in memory), and then parse it a second time (especially with compressed LAZ files for instance).
Daniel, CloudCompare admin
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