Feather template on Hairgen

   596   3   1
User Avatar
Member
3 posts
Joined: Dec. 2021
Offline
Hi there,
I have been following this feather tutorial series:

https://www.youtube.com/watch?v=pOjHpX0NOi4&t=65s [www.youtube.com]

I'm at the point where I have one feather distributed on a hairgen but the feathers are spawning from halfway along the feather, inverted in shape and also stretched in shape.

Did I miss something obvious?

Houdini 20.0.648

Attachments:
Feather.jpg (117.2 KB)

User Avatar
Member
3 posts
Joined: Dec. 2021
Offline
To follow up, here is a default feather template attached to a hairgen on a grid - the shape of the barbs is errored (bottom image) in the default orientation.

They look as expected if using a guide process direction to lay them flat to the grid

Also interesting note.. in the tutorial series linked above, he seems to have an unnoticed issue where the feathers have a different shape when being created on the guide groom
Edited by markusAkino - Oct. 1, 2024 17:10:16

Attachments:
BarbFine.jpg (95.2 KB)
BarbsErrored.jpg (62.6 KB)

User Avatar
Member
123 posts
Joined: Dec. 2019
Offline
Hello,

This behaviour is due to an incorrect configuration of barborientattribute.

The Orientation Along Curve SOPis not appropriate for setting up barborient, as it builds orient quaternion using a Z-axis going in the curve direction.

Feather tools in Houdini treat barborientlike if it's built in the opposite direction of Z-axis (negative Z direction).

You can use the Guide Tangent Space SOPas it's more appropriate for Groom/Feather tools. For example, using the "Skin Tangent Attribute" mode over skin's N(normal) attribute gives an orientation that feels more "natural".





Edited by ObeidaZakzak - Oct. 2, 2024 13:25:09

Attachments:
GuideTangentSpaceBarbOrient.png (2.5 MB)
GuideTangentSpaceBarbOrientAttribViz.png (2.0 MB)
OrientationAlongCurveBarbOrientAttribViz.png (1.9 MB)

Houdini Pipeline Supervisor @ TAT Studio
User Avatar
Member
3 posts
Joined: Dec. 2021
Offline
Amazing,
Thanks very much ObeidaZakzak
I really appreciate the detailed response
  • Quick Links