spherical deformation

Forums Technical Discussion spherical deformation

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Manaskin: Member; 15 posts; Joined: Aug. 2010; Offline

Aug. 23, 2011 10:17 a.m.

Is there any way to project a geometry (not a texture!) eighter curves or polys on a sphere?
A normal projection won´t work, cos it´s flat.

I tried using a VOP SOP, but I´m not familiar enough with all those mathemetical parts.


edward: Member; 7718 posts; Joined: July 2005; Offline

Aug. 23, 2011 11:39 a.m.

Perhaps a Ray SOP will work?


brianBurke: Member; 192 posts; Joined: Nov. 2008; Offline

Aug. 23, 2011 12:07 p.m.

here's a way of doing this in a vop sop.

projecting on a unit sphere is as easy as normalizing point position, so if you have the radius and the center of the sphere to project on, you just need to scale and position that unit sphere to match the projection target.

Attachments:
project.jpg (178.9 KB)
project_to_sphere.hip (205.9 KB)


Manaskin: Member; 15 posts; Joined: Aug. 2010; Offline

Aug. 24, 2011 8:54 a.m.

Very Nice approach,
but my problem is that I need a full 360 ° that distribute equally based on their postions, your version is 180° and appears to bulge if I take an even structure like a grid.


aiworks: Member; 130 posts; Joined: April 2009; Offline

Aug. 25, 2011 5:55 a.m.

How about first using RAY to put your geometry on a flat plane, and then CREEP the result onto the sphere or any other object? Should work fine for 360 degs.

Cheers,
Greg

Attachments:
iopetus.png (30.4 KB)


Manaskin: Member; 15 posts; Joined: Aug. 2010; Offline

Aug. 25, 2011 12:03 p.m.

Thank you, that´s exactly what I need.

That´s the kind of things I love about houdini, there is a hidden node for everything, you just got to find it :-)

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