Forums Houdini Indie and Apprentice How to manage the unwrap direction based on geometry position in 3d space?

How to manage the unwrap direction based on geometry position in 3d space?

   1915   5   1
User Avatar
Flatland
Member
43 posts
Joined: Dec. 2017
Offline
 
Hi guys
i have a very simple geo which is need to unwrap. I'd love all the faces to have the same orientation towards the vertical direction (as you can see, that's a roof, it's very useful for roof tiles!). obj in attached for those who want to try

Image Not Found



All i need is something like this, but done procedurally




How would you do that?

Attachments:
roof geo.obj (3.2 KB)
roof.JPG (92.8 KB)
roof unwrap.JPG (43.8 KB)

 Report
User Avatar
Konstantin Magnus
Member
670 posts
Joined: Sept. 2013
Offline
 
You can orient the polygons by the direction from vertex 0 to vertex 1.

Attachments:
roof_uv_winding.jpg (26.3 KB)
roof_uv_raised.jpg (32.0 KB)
roof_uv.hipnc (184.5 KB)

https://procegen.konstantinmagnus.de/ [procegen.konstantinmagnus.de]
 Report
User Avatar
Konstantin Magnus
Member
670 posts
Joined: Sept. 2013
Offline
 
In case of randomly shifted vertex orders or if you want to keep it more generic you could also build rotation matrices based on the primitive normals:

vector nml = prim_normal(0, @primnum, vector(0.0));
vector up = set(0, 1, 0);
vector x = cross(nml, up);
vector z = cross(nml, x);

3@r = set(x, nml, z);

Which gives a visually similar result:

Attachments:
roof_uv2.hipnc (185.9 KB)
roof_uv_prim_normals.jpg (31.6 KB)

https://procegen.konstantinmagnus.de/ [procegen.konstantinmagnus.de]
 Report
User Avatar
Flatland
Member
43 posts
Joined: Dec. 2017
Offline
 
Hi Konstantin
that looks awesome, does exactly what i need. I'm going to have a better look at it, as i'm not into matrices as i should.

Thanks heaps
 Report
User Avatar
Andr
Member
900 posts
Joined: Feb. 2016
Offline
 
just stopping by to say thanks for sharing this nice technique
cheers
 Report
User Avatar
Konstantin Magnus
Member
670 posts
Joined: Sept. 2013
Offline
 
I made another variant that keeps the surface geometry intact at all times (no faceting and fusing needed), and also makes the tiles match.
Edited by Konstantin Magnus - June 2, 2019 11:39:37

Attachments:
UV_roof_tiles.jpg (33.3 KB)
roof_uv3.hipnc (185.5 KB)

https://procegen.konstantinmagnus.de/ [procegen.konstantinmagnus.de]
 Report
  • Quick Links