How to mesh the model into elements

[xl539@cam.ac.uk]

I built a sand ground model where it suffers from three-dimensional movement. And when I tried to calculate the difference between two DEMs, it appears many noises as I can't match the same sand particals.

Can I mesh the model into many square areas and get the elevation in each meshed element instead of pixel?

[olihar]

Decimate before comparing.