Hi
Let me describe what I mean on an example

I have a window procedural asset with kind of complicated frame geometry profile wise.
The core aspect of window HDA is ability to change its size.

How to force frame UVs to align all horizontally or vertically?
When the window is high and narrow some uv islands reorient themselves, while I need them all to point the same direction i.e. to assign wood texture.

Basically such consistency in UV alignment is needed to any furniture made of wood like chairs, cabinets, shelves etc.

What is the best way to achieve that if the shape of geometry is not simple as box and manual pre-UVing is required?
Essentially how to procedurally relax and repack geometry without destroying initial orientation of UV islands.

Thank you Guys for ideas, I'm new to Houdini and still discovering it.

Hi
this is actually quite tricky.
One tip here is to use the http://www.sidefx.com/docs/houdini/nodes/sop/uvlayout.html [www.sidefx.com] node
and set Orientations to 1 .
This will help, but probably not fully solve your issue.

You will need specify while modelling the general UV direction of each piece you build…
How to do that not that straight forward and very depending on what and how you model..

greetings

Olaf

I was thinking of having one edge per uv island being grouped and then use that edge as uv direction of piece.

Can anyone provide idea how to:
- set uv orientation of defined edge
- orient uv island to the uvorientation of defined edge?

On the other hand I think it will be very useful if houdini has individual nodes for: just relaxing (in place) and packing (without orient)
I used modo for quite a bit of time and modo has Pack UVs tool with check-boxes (pack, strech (relax), orient uv shells) it would be great to have such flexibility in Houdini - to limit on demand functionality of nodes.

The uvflatten sop has an Axis-Aligned Vertex Groups section where you can enable axis alignment. The aligned groups expects vertex groups but if you can define an edge group then promote to a vertex group and use that as the aligned group, it will align the UVs parallel to either the U or V axis, whichever you select. It doesn't work across multiple UV islands but you can throw the uvflatten into a for-each loop to process each UV island separately.