too many groups


As i study metallic foam structure so to introduce pours in a crystal block, i’m using “group” and “delete_atom” commands, but unfortunately # of group including other groups in my input script exceeds 32. Normally lammps gives error “too many groups”.
As each group assign one pour in my input so obviously it will greater than 32.
is there any way to create such geometry which contain pours ( with different shape and size ) i.e looks like a foam without using group and delete_atom command ?
I saw porosity command but as i wish the pour dimension and size would be user defined so the porosity style would be not suitable.

can you suggest another software package which helps me to create this type of model geometry?
please make some comment.

best rgds


if you don't need a group after you used it to create atoms,
you can delete it and then create a new group. that should
get you past the 32 group limit.


Hi axel
thanks but axel how can i delete a group by command after use ?

Is there any other software package or technique by which i can make such model with many pours.


read the documentation and check your spelling. There is a group delete command and you are talking about pores, right.

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Hi axel

sorry ,no wait…sighs i have found “group” command with style “delete”.Thanks it really works fine.

Beside this i have another question-
as i wish to make a nano porous foam model so in lammps input script i’m invoking pores by delete_atoms command but it really a worst job to define individual pore center and radius(if i consider spherical pore).So is there other way to make this type of foam model with required porosity.
I have visited your web-page, i saw topotools. Is this topotools can help me to make such geometry?

thanks in advance.



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