Hi,
For ezsurf, it is unable to specify external variable. The workaround is that
1. Hardcode the variable with the actual value, e.g.
f = 'x+y*100'
ezsurf(f)
2. Format the input string for ezsurf, e.g.
scale = 100
f = sprintf('x+y*%f', scale)
ezsurf(f)
Let me know your special requirement.