[Question] about Agisoft Metashape data conversion

[sanskar107]

I believe that agisoft follows colmap camera convention (right, down, forward), whereas nerfstudio follows right, up, backwards. So while data conversion, we just need to negate the second and third row of transform matrix ([x,y,z] -> [x,-y,-z]). But there's an extra axis rotation in the conversion script here... https://github.com/nerfstudio-project/nerfstudio/blob/main/nerfstudio/process_data/metashape_utils.py#L183

Why convert [x,y,z] to [z, x, y], and then change the sign to [z, -x, -y] ?

[kkodamakazusa]

As you mention, I also think some edit in metashape_utils.py make good result.

at line 142 and 143, m[:3, :3] = r, m[:3, 3] = t/s --> m[:3, :3] = r*s, m[:3, 3] = t. and comment out the line at182, transform = transform[[2, 0, 1, 3], :]. by this change, I obtain pcd model with same coordinate in metashape. (I also use "--pipeline.datamanager.camera-optimizer.mode off nerfstudio-data --orientation-method none --center-method none --auto-scale-poses False" option when training)

[Yaodizhao]

May I ask if I can convert the generated point cloud back to the original data, but there is a significant difference when I perform calculations. May I ask if you can give me some help