The normal vector of a surface indicates it

but the result is same value (0,0,-1)

i use the node " vector dot " to find a plane that is not parallel to the x-axis…

but is this right approach?

and is there a way to seperate a list with the same value …

hlep me ㅠㅠ please…

@RubenVivancos is correct as far as I know - the normal at parameter 0.5/0.5 (middle) for a planar surface not at the XY plane should have a Z component less than 1 in the absolute form when in unit format.

sample.dyn (17.6 KB)

i want to find a

diagonal plane… ㅠㅠ

how can i do

If all your faces are returning that vector then they must be pointing downwards at the sampled point from a normal perspective I think. Can’t really help beyond that, the script I attached works with the basic sample project so try it there as a sample of the logic.

I agree with @GavinCrump - by the looks of it you are not getting the desired results because os some other aspect of the graph. Likely best to share a data set.