File sizes Metashape vs Photoscan

[paulwright]

Apologies, I could not find anything that answered my query...

I am trying to reproduce a tiled model generated by a colleague with the 'last' version of Photoscan. According to him, he ran this at Ultra High settings for generating the point cloud, and High face count for the mesh.

I have done the same, but in Metashape, and my resultant files are significantly larger than the ones he generated (and thus the final product is either unmanageable, or, in one model, I run out of memory when it was original done on a relatively old, under powered PC at work!).

In the upgrade, has anything changed in the way these quality parameters work. I would have hoped similar quality files would have got smaller not larger!

Thanks

Paul

[Alexey Pasumansky]

Hello Paul,

Can you please specify the parameters of the Tiled Model generation procedure used in Metashape and, if possible, the tiled model parameters section from the Chunk Info dialog of the old PhotoScan project?

[paulwright]

Hi Alexey

Sorry, it has taken me some time to get the comparison data. The file attached shows a comparison of the same images run on a low powered machine on Photoscan 1.4.3 and on my own higher spec PC via Metashape 1.6

To my untutored eye, the major issue is in the tiled model generation. This version of PS only seems to have mesh and depth maps as source, whereas, at home, I used densified point cloud. The time to generate a model has increased. The final exported Agisoft zip file of OBJ, MTL, and JPGs is SIGNIFICANTLY bigger with Metashape.

Hope that helps diagnose the issue.

Cheers

Paul

[Alexey Pasumansky]

Hello Paul,

I see that in Metashape the tiled model has been generated from the dense cloud, whereas in PhotoScan already reconstructed mesh has been used as a source.

[paulwright]

OK...when I am at home I will rerun my models using this data source....will that make a serious difference?

[Alexey Pasumansky]

Hello Paul,

When you are using the dense cloud as a source, the mesh blocks on the most detailed level are generated using Poisson reconstruction, then lower level tiles are generated from them. In case the mesh is already present and used as a source, you almost have the most detailed tile level.

So I can suggest to try using mesh as a source in Metashape and then compare the timing and tiled model size with PhotoScan. The default resolution for the dense cloud based tiled model may be higher than the resolution for the mesh source, therefore additional LOD levels could be generated, which result in bigger size of the model.

[paulwright]

Hi Alexey

So running the tiling off mesh did save some time and memory...3h45m went down to 2h22m, and 1.9GB fell to 1.4GB, but that is still much higher than the 1h38m, 392MB effort on Photoscan.

I have tweaked the face count parameter (which PD does not have) to Medium....final result is 1h 36m at 706MB, which is much more useable. The issue was getting usch a large tiled model into the Unity games engine...it just took forever (And frequently crashed)

Thanks for your help

Paul

[Alexey Pasumansky]

Hello Paul,

The default face count value for the tiled model is Low, which corresponds to 4000 faces in the older versions as well.

[paulwright]

Excellent...that will be it then, as I know they never changed that value.

Thanks for your input, it has really helped our workflow.