LAS intensity issue

[max72]

I have some issues with a 2.6.1 and win7x64.
I have an intensity only cloud, and if I export it to E57 everything is ok, while with LAS the intensity is lost.
In the test I did the following:
Segmented a small subset and saved to bin (attached).
Opened the bin and saved as E57 and LAS.
The LAS looses the intensity.
With my laptop I have not this issue.
In the past it worked fine also on this PC. Only thing is I modified (before starting using CC) the language setup to allow the "." as a decimal separator in place of the "," we are supposed to use in Italy..

Massimo

[daniel]

The problem is simpler: according to the specifications, LAS intensity is an integer value (16 bits - i.e. between -32K and 32K).

Therefore, if you try to save intensities between 0 and 1 they will be 'rounded' to 0 (and then ignored at loading time by CC).

Simply multiply the intensity field by a big value (10 000 for instance). You can use the 'Edit > Scalar fields > Add constant SF' and the 'Edit > Scalar fields > Arithmetic' tool (http://www.cloudcompare.org/doc/wiki/in ... Arithmetic).

[max72]

Thanks!
You are right.. I was looking for complex solutions, while the answer was so simple..
I also made the mistake to not use the same cloud on both computers.. that would have been a more sensible approach..
Cheers,
Massimo

[jansawicki]

Hi,
Multiplying the intensity field by a value of 10 000 works great, although is there any way to apply this operation using command line? It seems to me that neither of * - + / operations are available with command line mode. Thank you in advance :)

[daniel]

Right now you can only apply such arithmetic operations between two scalar fields. We should add the option to use this with a single value to the TODO list.

[daniel]

Ok ,the latest online 2.6.3 version has a new 'SF_OP' option to apply simple arithmetic operations to a scalar field (+,-,*,/). See the wiki here: http://www.cloudcompare.org/doc/wiki/in ... _line_mode.

[jansawicki]

Hello, same problem again...
I don't know, multiplying by 10k worked before, but now (CloudCompare v. 2.6.3 and 2.7.0) I get an error message:

[LAS] Found a 'Scalar field' scalar field, but it doesn't match with any of the official LAS fields... we will ignore it!

I'm trying with different scalar field ranges (using arithmetic functions), <-32K;32K>, <0; 64K>, <0;1>, <-1000;1000>, <0;1000>...
How do I make intensity values match "official LAS fields"? Any suggestions?

(The reason I want to convert my PTS files to LAS with color/intensity is that I want to Potree viewer, maybe there is an easier workflow for that?)

Thanks again

[daniel]

In fact it's mostly the name that should match ('Intensity'). And then I believe intensity values should be between 0 and 65535 (16 bits).

[jansawicki]

Thank you so much Daniel, it solved the issue!

[tallan34]

Hi All,

I was wondering if people could help me solve a similar issue.
I have imported some merged scans as .las and .laz files from GeoSLAM Hub, hvaing used a Zeb Revo the device for a small building survey. The data was processed in GeoSLAM Hub.

When I import the data into Cloud Compare, there is no option within the property section to add the colour or change it. I ideally want to display the data in a RGB format with multiple colours shown by intensity of the scan data.

Hope to get some help soon!
Thank you