findVertexAttrib return

[majikal]

Hi!

if geo.findVertexAttrib("uv") == ():
    uv_attrib = geo.addAttrib(hou.attribType.Vertex, "uv" , vertPos )
else:
    uv_attrib = geo.findVertexAttrib("uv")

It say that findVertexAttrib return None if attribute doesnt exist. I tried to compare it to () and "None" but nothing works.

To what should i compare return of findVertexAttrib to see if it exist. What is None? Empty touple?

ty

[graham]

Comparing to () will definitely not give you the correct result because an empty tuple is not equal to None. Comparing to None should work no problem; it always has for me.

>>> geo.findVertexAttrib("asdf") is None
True
>>> geo.findVertexAttrib("asdf") == None
True
>>> geo.findVertexAttrib("asdf") == ()
False
>>> geo.findVertexAttrib("uv")
<hou.Attrib Vertex 'uv' (3 Floats) of geometry in /obj/geo1/texture1>

If you want to test for an attribute and if not create it then your code should work fine. I personally always use this since it's slightly less work.

uv_attr = geo.findVertexAttrib("uv")
if uv_attr is None:
    geo.addAttrib(hou.attribType.Vertex, "uv", (0.0, 0.0, 0.0))

Edited January 25, 2010 by graham

[majikal]

thank you... it works..

i looked it up and saw that none is type.

is it possible to solve the same problem with try except

something like this:

try:
    uv_attrib = geo.addAttrib(hou.attribType.Vertex, "uv" , vertPos )
except hou.OperationFailed:
    uv_attrib = geo.findVertexAttrib("uv")