Surface error when I create in grasshopper

anyone can explain why my surface got like this

Assigned to Grasshopper category

Hi Jeftli -

You are looking at two surfaces right on top of each other. That causes Z-fighting where one surfaces is drawn over the other in some places and the other in other places.
You can either hide the Grasshopper surface or the Rhino surface.

But how the surface have grid, i do imitate like this photo, grid not showing, just flat surface(red), i do, Set 1 curve to my rectangle, and i connect to surface mesh, and i put number slider, but grid not show

(This photo not my project)

Use Ctrl+M to turn on mesh edges.

1 Like

Nailed it, thanks for your advice