Default box size for ab-initio jobs

3D Reconstruction
1

Hi cryosparc experts,
I did the motion correction, CTF estimation, auto picking, and particle extraction in relion 3.0, the box size I set is 256 pix. After the particle extraction, I tried to import particles.star file to cryosparc, the importing and 2D classification jobs worked well. However, when I carried out Ab initial reconstruction， the output mrc file showed the box size is 128 pix, I don’t know why. Does anyone know what happened to the box size? And how to keep it the same 256？
Yours sincerely，
Lingting

2

Hi Lingting,

128px is the default box size used for ab initio reconstruction (at the default start/final resolution values). This is for speed, to reduce computational cost - there is no need to run in a box size of 256 if you are using a maximum resolution of 12 Å, and the resulting volume will be automatically resampled in subsequent refinement jobs.

Cheers
Oli

3

Hi Oli,

Thanks for your reply. I got it.

Best,
Lingting