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Dear Blender Community,

Working on following Idea, I had a few problems:

The original Idea:

So I was trying to create an Extrusion Plus Nodegroup, where I can easily control the Extrusion Length, the Rotation (really the Rotation Offset from the original Normal) and the Scale. Also this Nodegroup should be compatible with Repeat Zones.

Right now it only works with extruding single faces, since I haven’t figured out how to separate the calculations for every Mesh Island. If someone could give me a hint that would be great!

To control the Rotation from the Extrusion Center, I set the position to Origin and afterwards back to the original Position, if there is a more elegant solution to this I would be glad to learn.

Here is my cureent Node Setup: Node Setup

The Setup repeated

The advanced Idea:

It would be great to be able to find the nearest point of a target geometry (i.e. a curve) from the extrusion, snap to that position, read the tangent of the point and align the extrusion normal to the tangent.

Resetting the Extrusion to an arbitrary Position other than the Original one should be easy, but aligning the Rotation seems like I bit off more than I can chew.

First I would need to reset the Extrusion so its Normal faces Z, which I can’t make work.

Would I need to sample the Target’s Tangent AND Normal?

If you have any Ideas regarding one of these problems or can point me to ressources for me to further learn I would be very grateful. I am still on the low intermediate side of expertise regarding Geometry Nodes, because my Math skills and Computer Logic Knowledge are bad.

Thanks in advance! Best wishes, todesdigga

Todes Digga
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    i think adding some images with annotations to show us how it should look like would help a lot! – Chris Jan 10 '24 at 12:03
  • @Chris Oh sorry I totally forgot to add the Screenshots, hope it makes more sense now :) – Todes Digga Jan 10 '24 at 14:44
  • btw you know you could use the center input of the rotation node. (it's the "more elegant" solution) – shmuel Jan 11 '24 at 01:05
  • Thanks shmuel, I did not get that to work, neither for single face extrusions nor multiple faces. I thought the process would be: Position > Vector Rotate > Set Position (with Top Selection), and for the Center also the Position but with an Evaluate on Domain set to Face. It wasn't. Do I need to set a Group ID per Face? And how would I feed that into Set Position? – Todes Digga Jan 11 '24 at 09:51
  • The reason I stopped trying to make the Vector Rotate Node work with anything other than zero at the Center Input was Markus von Broady's answer here: https://blender.stackexchange.com/questions/278367/what-is-the-center-in-vector-rotate-node It seemed the best option is to first Center my Extrusion at 0,0,0 and reapplying the original Position after rotating, since I did not really get the Implications of Robin Bett's explanation... – Todes Digga Jan 11 '24 at 12:10
  • This answer also did not work for me: https://blender.stackexchange.com/questions/268570/rotate-each-face-on-their-own-axis-in-geometry-nodes Set position with Top selected and Position evaluated on Face Domain for Center of the Vector Rotate still gives me a weird Pivot Point which is not the Center of the extruded Face. Is the problem that the Vertices of the extruded Face are also connected to the rest of the mesh? I understand that everything gets more complicated if its several Faces being extruded, but with just one face?? Rotating an extrusion around itself seems like a common idea? – Todes Digga Jan 12 '24 at 12:00

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