Hi everyone
I’m working on a vase script it works but I have a problem
I want it to always select the top surface of the vase, for the shell polysurface. this is the always the first trimmed surface in the list. the way it works now, you have to manually change the top surface (changing the number in the lower panel).
can some one help me out?
Grasshopper help top surface.gh (17.0 KB)
You can compare the surface normals to the Z vector. The dot product of the top surface normal and Z vector should be 1.
Thanks for the reply
How would you make this? I’m still new to grasshopper
thank you 
Shelling maybe?
I’m not a Pufferfisher… 
I guess I haven’t followed this thread. How did you solve it? 
Why is the selection of horizontal surfaces ignored?
I don’t understand.
I think the user wanted to get the index of the top surface. I did not look at the rest
I’ve made many vase shapes like this and I too was confused by the OP. A real vase will not have a closed top, right? So the question about establishing a top surface did seem odd.
A vase shape needs an inside, an outside, and a bottom that has some thickness - typically equal in thickness to the sides of the vase. Once the outside shape is established the rest is easy. In this case making this:
In general I try to avoid SDiff, but in this simple case it is not a problem.
Grasshopper_help_top-surface_dot-product_mrtn-bb1.gh (23.3 KB)
I think the Pufferfish shelling component might require you to provide the face index where the opening will be.
