Forum

Author Topic: Subsampling the dense pointcloud  (Read 4307 times)

Ingsayyad

  • Jr. Member
  • **
  • Posts: 89
    • View Profile
Subsampling the dense pointcloud
« on: September 13, 2017, 11:01:29 AM »
Is there any way to subsample the dense point cloud. e.g., 1cm/1mm, etc.

SAV

  • Hero Member
  • *****
  • Posts: 710
    • View Profile
Re: Subsampling the dense pointcloud
« Reply #1 on: September 13, 2017, 12:42:41 PM »
Hi Ingsayyad,

Unfortunately it is not possible in PhotoScan. You can only 'subsample' a mesh using TOOLS > MESH > DECIMATE MESH.

However, you could build your dense point cloud at a lower quality which would result in less points.

Alternatively, you could export your dense point cloud as *.las or *.laz file, open it in CloudCompare (free, open-source) and perform the subsampling there. Here are the details: http://www.cloudcompare.org/doc/wiki/index.php?title=Edit%5CSubsample
This is probably the best option. Note that CloudCompare allows you to subsample your point cloud in a smart way by changing the point density based on the curvature, which means that in highly curved areas which are geometrically complex there will be more points preserved in comparison to flat areas with a low curvature.

I hope that helps.

Regards,
SAV

« Last Edit: September 13, 2017, 12:46:35 PM by SAV »

toxicmag

  • Jr. Member
  • **
  • Posts: 88
    • View Profile
Re: Subsampling the dense pointcloud
« Reply #2 on: September 18, 2017, 12:56:04 PM »
Hey SAV,

i totally agree on that subsampling issue based on curvatures. It's great feature.

But - once you leave PS there's no coming back with regard to texturizing the model, right?

Greetings

Alex
#multirotor #VTOL #Trinity #Quantum-Systems #a6000 #a7R #RedEdge #ALTUM #RX1II

SAV

  • Hero Member
  • *****
  • Posts: 710
    • View Profile
Re: Subsampling the dense pointcloud
« Reply #3 on: September 18, 2017, 04:57:04 PM »
Hi Alex,

Yep, you are right. PhotoScan does not allow to import dense point clouds. However, you can import meshes.

Therefore, you could generate a mesh in CloudCompare from your filtered/subsampled point cloud and then import it into PhotoScan to generate a texture.

Note that CloudCompare is not really designed to handle meshes, but it has some (limited) meshing functionality. Here are the details: http://www.cloudcompare.org/doc/wiki/index.php?title=Poisson_Surface_Reconstruction_(plugin)

Let me/us know if it worked for you.

Regards,
SAV

Hey SAV,

i totally agree on that subsampling issue based on curvatures. It's great feature.

But - once you leave PS there's no coming back with regard to texturizing the model, right?

Greetings

Alex