Potree Generation Information

[s093294]

I was not 100% sure where to post this question. Might not be directly related to python scripting but more general scripting.

I was amazed by the potree exports of photoscan and I have been trying to generate potree files myself (https://github.com/potree/potree) but have not been able to get similar details from my exported point clouds from photoscan.

Are you using the same tools to generate them as on the github? Would you be able to share alittle input on what kind of arguments is needed to get similar detailed results as coming out of photoscan directly.

Can we extract them from python also?

[BarryReid]

I would also like to know how to export potree in python

[Dmitry Semyonov]

PhotoScan potree exporter is based on the following paper:
http://potree.org/downloads/converter_documentation.pdf
It is a built in PhotoScan feature, and not just a Python extension.

While the general tree construction approach is the same as suggested by original author, some implementation details might be different. Still I believe that PotreeConverter should provide similar outputs to the ones obtained in PhotoScan if octree depth and spacing are properly specified.

For dense point clouds exports we recommend to set spacing to the ground sampling resolution multiplied by the quality factor (1 for Ultra High, 2 for High, 4 for Medium, etc). Octree depth should be set to a minimum value, which provides specified spacing on the finest octree level.

[BarryReid]

I am hitting the problem where the export from the GUI and the export from the Python API are not at all the same.

The GUI export has a folder in the zip file called "data" and is full of files that are then referenced in the JS file. However when you do an export using the Python API, you get no "data" folder in the zip file and the JS file has completely different data in it, only the structure is the same.

My Steps:
1. Open project file
2. Click "File", "Export Points", Type name and select "Potree" as file type, Click "Save"
3. Make sure "Dense cloud" is selected, Click "OK"
4. Export should start

5. Run the following line in the CLI "PhotoScan.app.document.chunk.exportPoints("/location/to/my/export/potree.zip", format="potree", source=PhotoScan.PointsSource.DensePoints)"

6. Compare outputs and they are not the same.

It seems that the script output is not generating any data, its kind of just a blank JS potree file.

Can anyone tell me what I might be missing or why this is happening.

[Dmitry Semyonov]

Hello Barry,

We just tried to export potree from Python and it worked fine.

Are you using the latest PhotoScan version (1.1.6)?
What operating system are you using?

[BarryReid]

Hi, I'm using version 1.1.6 on Ubuntu 15.04

[BarryReid]

Any Ideas? Still cat get it to work.

PhotoScan.app.document.chunk.exportPoints(location + projectName + "_potree.zip", format="potree", source=PhotoScan.DensePoints)

Exports pretty much a blank potree zip file with one js file in it and no data.

[Alexey Pasumansky]

Hello Barry,

We've checked and compared GUI and Python based exports to potree on several OS variations and have not yet encountered any difference.

We've managed to get empty zip with a single js file, but only after removing all of the dense cloud points.