I want to get the centroid xyz and normal xyz of a series of polygon.

I used the following in a python node but it didn't work…

prims = hou.pwd().geometry().prims()

for prim in prims:
x = prim.attribValue(“P”)
print x

advise is appreciated!

- Ji

position = sum((vert.point().position() for vert in primitive.vertices()),
hou.Vector3()) * (1.0 / primitive.numVertices())

normal = primitive.normal()

Thank you very much, graham!

learned new trick, again!

- Ji

the use of the sum() function as explained in:
Code Like a Pythonista: Idiomatic Python

http://python.net/~goodger/projects/pycon/2007/idiomatic/handout.html [python.net]

- Ji

Keep in mind that for polygons other than triangles and parallelograms, that gets you the centroid if the mass is equally distributed among the vertices, not the centroid if the mass is equally distributed over the area, which is a lot harder to compute. Of course, for many purposes, it doesn't matter which you use; just thought I'd let ya know!

noted with thanks, ndickson! - Ji