GH Python : Friction - syntax error on Normal Vector

[wim (Wim Dekeyser)]

Hi - please don’t double-post…

GH Python : simple gravity problem

Dear All, I have been following a tutorial from Jake Hebbert’s channel on Youtube and trying to make a simulation of a bouncing ball with friction and gravity constraint but the animation (simulation) was moving very slow and I have a syntax error to define “normal”. I hope anyone can help me. Thank you[simple gravity and fraction.gh|attachment] (15.3 KB)

-wim