Revolve SOP and procedural UV

[deliriumtrip]

Hey guys,

How do you go about UV ing revolved surfaces procedurally?

[edward]

If a NURBS surface, then UVTexture set to Rows and Columns.

[3__]

try these via point SOP:

 

pre revolve mapv =

$PT/($NPT-1)

post revolve mapu = 

($PT % (ch("../revolve1/divs")+1)) / ch("../revolve1/divs") 

[deliriumtrip]

Thanks a lot!
Both methods seems to work, one for NURBS, another for Polygon
 
But than I use point SOPs with Polygon curve (and Revolve set to Open Arc to avoid issues with UV overlapping), I see some distortions

Maybe somebody knows, what's going on?

 

By the way, how can I attach a hip file to my post?

 

Edited March 30, 2015 by deliriumtrip

[3__]

see attached...

for polys use refine SOP to avoid stretching,

for nurbs you can eyeball it with a refine SOP... there might be a more procedural way to do this.

 

also the distortions in your screenies should only appear in the viewport, adding more revolve divs will get rid of them.

 

to attach files, click on more options button next to 'Post'

mapped_revolve.hipnc

Edited March 31, 2015 by cpb

[deliriumtrip]

cpb, thanks a lot!
It's really helpful.

Regarding distortion- I guess it's a very basic stuff, I was not aware of.
it appears only on very low poly with low Revolve devisions and curve set to Polygonal and has the same nature as one described here http://blender.stackexchange.com/questions/3156/how-to-map-a-texture-to-a-distorted-quad
it comes from the fact, that any standard renderer ( like Houdini viewport) triangulate the quad first, and only after that interpolate UV coords to these 2 separate tris.
It looks like UV coords should be distorted just like a geometry quad, they are applying to

 

Update: the distortions are quite simple to remove by using custom shader, like described here http://www.reedbeta.com/blog/2012/05/26/quadrilateral-interpolation-part-1/

Edited April 17, 2015 by deliriumtrip