CloudCompare forum

Hello,

for quite a while I have been looking for a free point cloud viewer for our extensive library of free and open AIRBORNE lidar data. You can download over 72,000 km2 of free lidar data here - http://geonb.snb.ca/li/

All of our data is stored in the LAZ compressed format. I am quite impressed with how simple it is to open an LAZ file and manipulate the viewing angle with ccviewer. However, I am not impressed with the options for changing the appearance of the point cloud. I see there are two shader options but I really want to be able to colour the point cloud by:

• point class (ground, building, low vegetation, medium vegetation, high vegetation, water, etc)

• intensity

• elevation

Is this possible with ccviewer?

Thanks,
Bernie.

Hi,

With ccViewer, you can change the current displayed scalar field: This lets you virtually look at any standard LAS filed (classification included).

However you can't change the color ramp (you'll always get the default one that automatically spans between the minimum and maximum values in the scalar field). And since the elevation is not a standard field you see it that way as well.

You would have more control with CloudCompare, but of course this is more complicated to use, and heavier to download.

Daniel,

Thanks for the reply but the "Selected entity" menu item is inactive. How do I activate it?

Can you (left) click on the entity in the 3D view?

Daniel,

I cannot reliably select the point cloud by clicking on it in the 3D view. I managed it once or twice. Why would that be? Perhaps you could give it a try with the same airborne data that I am using? It is compressed in the LAZ format. It is a 1 km x 1km tile with about 10 million points. The buildings along the north edge of the tile are a nuclear power plant:
https://geonb.snb.ca/downloads2/lidar/2 ... 340000.laz

If I only have one entity in ccviewer why do I have to select it to change parameters? Why isn't it selected be default?

Bernie.

It's not selected by default because:
- the bounding-box is not very nice (and the viewer is mostly here to show nice things ;)
- some file formats contain multiple entities

I can pick your cloud without any issue: The picking mechanism relies on a dedicated OpenGL feature. It happens (more and more) that some drivers don't handle this feature. However if it was the case, you wouldn't be able to pick the cloud at all... I'm not sure what happens exactly on your side...

Which version are you using by the way?

Oh, and for the records, here is what this cloud looks like with Classification + EDL shader:

One more thing if just left clicking on the cloud doesn't work for you holding down ALT key while dragging a box around some part of the cloud seems to work still even when the left clicking by itself does not.
I assume we are doing CPU based picking for regions