Conversion from point cloud to mesh not working

[markKs]

Hello everyone,
I struggle with a simple conversion :-(
So I have imported my las drone laser scan file of a forrest. In the Workflow there is no "build dense cloud" function, so I say "build mesh" > works. But the generated mesh is very blob-like. Very rough. If I increase the face count, that does not help.

Should be a simple thing I guess. Do I need to build a dense cloud first?

I attach the image. In the front you see the region, that was already converted to mesh and is very rough. Also some colors are lost during the conversion to mesh (you can see some cyan points that were a house and are not in the mesh).

Thank you very much

best from Berlin,
Mark

[JMR]

Hi, Mark:
It looks like you are building the mesh from the sparse point cloud (tie points), you should rather use either "from depth maps" or "from dense point cloud" methods.
The latter will take longer, and the results may be slightly different but also in return you will have the opportunity to classify the dense cloud prior to mesh and filter by class the points you want to use for meshing.

Regards,
José Martínez
Accupixel & Geobit
Metashape training

[markKs]

Dear José Martínez,
thank you very much for the fast answer. However I cannot find "from depth maps" or "from dense point cloud"  under the "workflow" tab. Does this only exist in the professional version?
Or is it missing because I started with the import of a .las file? And not with dragging in photos.
A hint would be great.
best
m

[JMR]

Sorry, Mark, I missed that you are trying to build a mesh from lidar points and not from photos. Yes, mesh form depth maps or mesh from dense cloud requires aligned set of photo to be available as the source options in the mesh dialog.
If your las is classified you might use ground class to get a DTM if it's not then you can try the ground classification tool and later do the same. Normally you cannot expect to have a nice mesh from forestry lidar data because the points are everywhere into the canopy structure and form a scattered "fog" inside, making it hard for the program to estimate point normals and thus deliver a detailed and accurate mesh. If you are lucky enough and have enough points hitting the ground, you can at least create a good terrain model... but yes, all are pro features.

 
José Martínez
Accupixel & Geobit
Metashape training

[markKs]

Thank you very much. If you mention, that there will probably no high quality mesh anyways, then I will directly use the point could in three.js by converting it to a PCD file using CloudCompare. Thank you!

[Alexey Pasumansky]

Hello Mark,

Does it give you a better result, if you uncheck Use as Laser Scan option from the context menu of the imported point cloud and then run Build Mesh operation using point cloud as a source option (using either extrapolation or disabled interpolation)?

[markKs]

Hey Alexey,
If I import without "laser scan" then I don't see the point cloud in the beginning. And if I build the mesh with extrapolation, then it appears. But quality wise it looks like before. Same with "disabled interpolation". I attach an image.

Do you think there is a way to get a better mesh result than the above posted screenshots? Because I realized that displaying a cloud in webGL is quite slow and a mesh would be way better I guess?

Thank you very much!
best,
Mark

[markKs]

I think I can create a good mesh quality if I import a higher quality point cloud file. However I still loose colors during mesh creation process. All is green and some cyan roof tops are also green. Any ideas on how to improve this? Turning off interpolation during mesh creation did not help.
thank you!

[Alexey Pasumansky]

I think I can create a good mesh quality if I import a higher quality point cloud file. However I still loose colors during mesh creation process. All is green and some cyan roof tops are also green. Any ideas on how to improve this? Turning off interpolation during mesh creation did not help.

Hello Mark,

Are you facing this problem in latest 2.0.2 version (build 16334)?

[markKs]

Dear Alexey,
I am using Version 2.0.1 (64 Bit) on a Mac M1.
thank you

[LRP]

I seem to be having similar issue. I imported laser scans to Metashape and manually added masks around the area I want meshed. I also classified various points of the laser scans. I then created a mesh using strict volumetric masks but the resulting mesh is unexpectedly blobby although I have interpolation disabled. I would have thought that there should be no mesh where I have applied the masks. It's almost like both the masks and disabled interpolation are being ignored. This is with 2.0.3 on PC.

[olihar]

Dear Alexey,
I am using Version 2.0.1 (64 Bit) on a Mac M1.
thank you

Can you please update to the newer build.

[Alexey Pasumansky]

I seem to be having similar issue. I imported laser scans to Metashape and manually added masks around the area I want meshed. I also classified various points of the laser scans. I then created a mesh using strict volumetric masks but the resulting mesh is unexpectedly blobby although I have interpolation disabled. I would have thought that there should be no mesh where I have applied the masks. It's almost like both the masks and disabled interpolation are being ignored. This is with 2.0.3 on PC.

Hello LRP,

Are you able to reproduce the problem with masks being ignored, if you use only single laser scan in the project and apply the mask over the corresponding spherical panorama?