forces on the walls

Hi all,

According to the doc pages for dumping the forces on the walls the command "fix mesh/gran/stressanalysis" should be used.

My problem is that I have imported the walls by "fix mesh/surface" and changing it to "mesh/gran" didn't work (got the error: invalid fix style)

It seems to me that "fix mesh/gran/stressanalysis" works only if you have used the "mesh/gran". So I was wondering what do you suggest for dumping the forces on the walls without changing the importating command?

Thanks in advance,
Danial