Simple (I hope) Procedural UV question

[stevegh]

So I have a circle I am sweeping along a curve, and I am assigning UVs to points with a simple attribWrangle with

f@u = float(@ptnum)/float(@numpt-1); 

 on the circle and

f@v = float(@ptnum)/float(@numpt-1)

on the curve and then a

v@uv.x = @u;
v@uv.y = @v;

and this works great except for the seam 1>0. Obviously I want to be using vertex attributes for UVs, and when I throw a UVProject on a tube I see that verts are indexed by prim # then vert #. How could I go about assigning UVs in a similarly simple matter but to vertices where for example my 0:0 vertex @uv.x = 1.0 and 7:1 @uv.x = 0.0, which are both point 0? Am I doing it wrong?

 

Thanks!

Edited June 29, 2015 by stevegh

[fathom]

use "vtxnum" instead of "ptnum" (and iterate over vertices and not points in your attribWrangle).

 

edit: hmm... rethinking this.

 

edit again: okay, well, "vtxnum" and "numvtx" would work for a single primitive, but i dunno a good way if you have multiple prims using vex.

Edited June 30, 2015 by fathom

[stevegh]

Heh, yea I just ended up doing it in a python SOP in a very non pythonic way. Set xsec and ysec on the cross section and backbone of the sweep, attribTransfer the ysec over to the result and chuck this in a python SOP:

node = hou.pwd()
geo = node.geometry()

xsec = geo.attribValue("xsec")
ysec = geo.attribValue("ysec")

for y in range(ysec-1):
    for x in range(xsec):
        prim = x + (y*(xsec))
        xinc = 1.0 / (xsec)
        yinc = 1.0 / (ysec-1)
        geo.globPrims(str(prim))[0].vertices()[0].setAttribValue("uv", (x*xinc, y*yinc, 0))
        geo.globPrims(str(prim))[0].vertices()[1].setAttribValue("uv", ((x+1)*xinc, y*yinc, 0))
        geo.globPrims(str(prim))[0].vertices()[2].setAttribValue("uv", ((x+1)*xinc, (y+1)*yinc, 0))
        geo.globPrims(str(prim))[0].vertices()[3].setAttribValue("uv", (x*xinc, (y+1)*yinc, 0))

Not pretty but works for me. Thanks anyways!

[kgoossens]

Another workaround you can do is

1. Unroll the circle before sweeping using the ends node.
2. Then after applying your uv's you can promote the uv point attribute to a uv vertex attribute using the attribute promote node
3. then fuse the points together.

[stevegh]

@Kim yup that works as well! Thanks!

[kgoossens]

And yet another method

 

 

Sweep-02.hipnc