How to select all surfaces in the same direction in Rhino

Rhino Rhino for Windows
1

Hello
I have an urban neighborhood and I need to select all the surfaces in the same direction in one click, how this can be done in Rhino?
Thank you

2

Is it to (temporarily) remove or hide the surfaces? 2 ways
1- select all the wanted surfaces and put them on a layer. when selecting the layer you select them all.
2- select all the wanted surfaces and group them. when selecting one, you select them all.

3

Hello - So, select one surface (planar?) and find all the ones that are parallel?
SelParallelPlanes.py (1.1 KB)

To use the Python script use RunPythonScript, or a macro:

_-RunPythonScript "Full path to py file inside double-quotes"

This does not ask whether the plane normals are facing the same way, but it can easily do so.

-Pascal