Metashape 1.6.5/1.7.2 observation on memory limit to alignment size

[andyroo]

I haven't seen updated alignment ram usage numbers lately so I figured I'd share my latest learnings. I processed two collections of 36 MPix aerial images with roughly the same geometry. The first was processed in Metashape 1.6.5 and the second in 1.7.2.

Working on a cluster with 384 GB of RAM, the alignment limit (on high) appears to be between 82,000 and 139,000 images, with the final step of alignment being the limiting factor (performed on a single node).

Maximum RAM usage to align 82,129 images was 173.18GB in 1.6.5.11249. If this scaled linearly, 139,152 images should take ~293GB of RAM. But we ran out of RAM on a 384GB node trying to complete the alignment stage in 1.7.2. with that number of images.

Obviously these are different versions, but wanted to share what I know.

Andy

[Alexey Pasumansky]

Hello Andy,

Usually we do not recommend to align more than 70 - 90 thousands of images in the single block (assuming that almost default parameters are used), as memory consumption and expected processing time rise dramatically at some point, due to the algorithm specifics.
I would expect more reasonable memory consumption for 10 000, 30 000, 50 000 image projects.

Instead of the outdated PDF that you are referring to, we have published the article in the Knowledge base which represent some information about memory consumption and processing time for common workflow operations for aerial and close range project examples: https://agisoft.freshdesk.com/support/solutions/articles/31000157329-memory-requirements-for-processing-operations