About the sead calculation by lammps code

I used the compute saed command in the lammps code to calculate the saed image of polycrystalline ortho-hexagonal polycrystalline SiC under different operating conditions. According to the criterion of tem diffraction image for polycrystalline, there should be circles in the diffraction spectrum, however, my calculation results show only diffraction points for single crystal. I checked the manual and found that inside, for Kmax (Maximum distance explored from reciprocal space origin) values only up to 6Å, while my grains have more than 6nm, I would like to know if lammps can implement saed calculations for polycrystalline materials?

The compute saed command does what its documentation says it does. Nothing more, nothing less. From the documentation it does not look as if it pays any attention to the content of the simulation cell, however, its output is determined by the various settings applied.