Orient on surface - how to perpendicular on z axis?

Hi I am trying to put trees on a sloping surface, but I can’t do perpendicular on z axis for trees.

Use the elevator mode.

rhino elevator mode - Suchen (bing.com)

Hi @Osman2
You can also use the ordinary Copy command and the the one-shot OnSrf Osnap when asked for “Point to copy to” (by either typing OnSrf in the command prompt or by holding down Ctrl over the Osnap panel). Note that Rhino will then prompt you to select the surface you want to orient on.

If you are looking to place multiple trees, there’s a bunch of scripts floating around for both Rhino and Grasshopper that will distribute geometry on a surface (either randomly or to specific points). Here’s CopyObjectToPoints (Python, so use RunPythonScript) and Sprinkler (which is a rvb, so drag’n’drop the file on Rhino and now you have a new command called Sprinkler).
HTH, Jakob
CopyObjectToPoints.py (515 Bytes)
Sprinkler.rvb (3.3 KB)