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Spin Copies

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peteski
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Joined: Dec. 2013
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Hi All!
Just a bit stuck with this. I was wondering, how could I rotate these copies with an attribute VOP?

At the moment what I'd do is create a spin attribute under the sphere node then stamp that onto a transform under the XYZ node but it feels like I should be able to avoid that and put it all into an orient attribute for the copy.
The problem is, the orientation is generated at the copy node so it doesn't really exist at the point where I have the attribute VOP.

Any ideas?
Thanks!
Pete




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mestela
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Joined: May 2006
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Try this in a wrangle:

vector aim;
matrix3 m;
float angle;
// calculate a matrix
// that rotates {0,0,1} down @N
aim = {0,0,1};
m = dihedral(aim,@N);
// create a random rotation angle per point
angle = @Time;
angle += rand(@ptnum,123);
angle *= fit(rand(@ptnum,456),0,1,-1,1);
// roate the matrix around @N by angle
rotate(m,angle,@N);
// define orient from that matrix
@orient = quaternion(m);

Attachments:
rotate_around_n.hipnc (88.3 KB)

http://www.tokeru.com/cgwiki [www.tokeru.com]
https://www.patreon.com/mattestela [www.patreon.com]
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peteski
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Joined: Dec. 2013
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Hey thanks mestela, that is ace but I was looking for something within VOPs. Menoz pointed me in the direction of this node - Make Instance Transform… [sidefx.com] (Make Instance Transform) and that is working great to grab the transform as the copy node would.

Thanks!
Pete
Edited by peteski - April 23, 2017 08:10:49
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Enivob
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2563 posts
Joined: June 2008
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Here is something similar but for instances.
http://forums.odforce.net/topic/29684-solvedvex-rotate-instances/ [forums.odforce.net]
Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.
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