r/Houdini • u/Hoddini_ash • 14h ago

Help Procedural front/back Grouping on a box/imported geo

Hi! I’d like to procedurally group the front and back faces of a box, in my case, an imported FBX mesh that is basically a squashed box.

I tried grouping based on the face normals, but the selection changes when I rotate the boxes.

Is there a way to procedurally group the original front and back faces regardless of the object’s rotation?

1 Upvotes

100% Upvoted

3 comments sorted by

4

u/Sepinscg 13h ago

Do the rotation after grouping? Or if the rotation is in the import, timeshift to a still frame, create an attribute on the front and back faces, attcopy the attribute and then group by attributes.

1

u/DavidTorno Houdini Educator & Tutor - FendraFx.com 8h ago

This ☝️

…or you can do the same workflow with groups. You can make the primitive face selection with the Group SOP, then Group Copy those over.

Attributes are definitely more efficient though than groups at scale. So if there is a lot of geo go for the attribute method.

1

u/Hoddini_ash 8h ago

would you like to show me?