Geo Nodes : tangents

[Kevin Mather]

Simple question, Blender 3.1.2

With geometry nodes, there is a trivial way to instantiate planes on the surface of a sphere (for example):

#0 Geometry Input
#1 Distribute points on faces
#2 Object Info (plane)
#3 Instance on Points
#4 Rotate Instances

Connect Rotation output of #1 to Rotation input of #4, and all planes are tangent.

If I replace #1 with “Mesh to Points” (because I want to use the vertex positions in the input geometry), it has no Rotation output. So all planes are parallel. Obviously I need to calculate normals and rotate them somehow.

It seems basic, but I can’t seem to find any help in the documentation. I must be missing something obvious.

Can anyone help? Thanks.

[Martin Bergwerf]

Hi @techworker1 ,

I am no expert on GN, but this sort of works in 3.1:

The Faces are Tangent to the Vertices, but they still have rotational freedom and although you can restrict that, it is not obvious what that rotation should be (especially with Suzanne).

Not the only way to do this of course and in 3.3+ you have a lot more possibilities even.

Hope this can get you started.

[Kevin Mather]

UPDATE: after a lot of messing around, I sort of got additional rotation to work. At least everything points to north pole. I tried adjusting a lot of different vectors to get a local Z-rotation, but always got nonsense. (Instead I rotated the source object.) I guess lots more study and experimentation are required.

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