Parametric, Ok understand that if you scale the trerrain the mat will keep the same ratio.

Still confused, about the material 'scale'.  If i apply a mat to the terrain and the mat is scaled at 0.7, how do i know that is the correct scale for the terrain that it is applied to?. If then i change the mapping to 'Pararmetric', yes i think i understand that the mat will scale at the same ratio as the resized terrain, BUT the mat could have been at the wrong size, before that So if i have a terrain that is say, 5km by 5km i then apply a grass mat who's scale is say 1.0. IF i then creae a terrain that is 50m by 50m and apply the same grass mat who's scale is 1.0, somewhere the grass is at the wrong scale for one of those terrains, I assume???

Regards