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Selecting alternating faces on sphere
Posted: 16 August 2012 07:20 PM   [ Ignore ]
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Is there a way to select every other face like a checkerboard pattern on a sphere primitive?
The “Select 1 over n” didn’t do exactly what I wanted, although setting it to ‘4’ was close.

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Posted: 17 August 2012 07:01 AM   [ Ignore ]   [ # 1 ]
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Unfortunately, it can’t be done.

A sphere (made of quads except for tris at the poles) in hexagon always has an even number of longitudinal sections (a sphere of “x” points has (x-1)*2 longitudinal sections).

Because this number is alway even, it means that any such sphere is ABLE to be checkerboarded the way you want, but you can only do it manually. The “problem” with hexagon’s “1 over n” algorithm is that it doesn’t have any kind of “offsetting” capability for adjacent layers.

Using the “1 over n” on a sphere means that n=0 always yields no faces selected, n=1 always yields all faces selected, n=2 always yields vertical stripes, and n=3 always yields diagonal stripes. Any n>3 yields some oddball pattern dependant on the ratio of n:x

And as intriguing as these “oddball patterns” may appear, you can’t even use any n>3 as a starting point in hopes of “filling in” the blank spaces, since checkerboarding it requires an even number for “n”, but offsetting adjacent rows of the sphere requires an odd numbered “n”.

I can post a tedious logical proof of that if necessary…  smile

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Posted: 17 August 2012 08:14 AM   [ Ignore ]   [ # 2 ]
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Thanks for the info!

I’m basically trying to make a spiked ball or turn everyother 4-sided face into a pyramid, but I’m having trouble making each one the same size.
Do you know of any tips or tutorials that may explain this?

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Posted: 17 August 2012 09:35 AM   [ Ignore ]   [ # 3 ]
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The easy ones I can answer grin

Use the geodesic sphere based on a cube, lower the number of segments what you want.  Then select the checker-board pattern manually - it can be done, but you need to be clever about it, otherwise you get adjoining faces.

Hit extrude surface, then be very patient while Hex thinks this out - otherwise it will freeze - it gives a funny sort of leap when its ready.

Then very carefully manoeuvre the mouse till you get what you want.

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Posted: 17 August 2012 10:35 AM   [ Ignore ]   [ # 4 ]
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Great I will give it a try!

 

 

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