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# Pattern On Surface, Repeating certain pattern on a given Surface.

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 Pattern On Surface, Repeating certain pattern on a given Surface. on Mar 23, 2008 at 1:00:24 pm

Hi, There!

I'm stuck with modeling a Sphere with frequently repeated patterned holes all over it.

Can someone please give me an advice, what would be the easiest way (automatically?) to model this, so the holes can be equally spread on the whole surface?

One of the problem is, that the Sphere is big and the patterns (holes) are small and doing this manually (one after another), would be a real waste of time.

I already tried with the following way: I made a pattern from PolyCube, and Duplicated it (function Duplicate Special, with rotating original pattern) so the patterns formed a shape of a Sphere. This caused a pattern overlaying/covering, which wasn't precisely. Then I combined this polygons. After this I made a Poly Sphere and wanted to make holes (with before mentioned combined patterns) with function booleans-difference.

The final outcome of duplicating was approx. 20.000 patterns (PolyCubes). Of course, this was a total blast for my poor system. And the other problem was, that after booleans-difference function everything disappeared.

After all the effort and time spent, I'm sure, there is a much clearer and simplier way of modeling this Sphere with holes all around.

Lea

 Re: Pattern On Surface, Repeating certain pattern on a given Surface.on Mar 24, 2008 at 4:54:25 am

What kind of pattern are you looking for? Could it be a gridlike pattern corresponding to the pattern of square faces making up your sphere? If so, you could just set the number of divisions on the sphere equal to the number of holes you want, then extrude faces (while keeping them separate) a couple of times to dig those holes.

If you're looking for a pattern that is more evenly spaced, without shrinking towards the poles, that's tougher. Your approach of duplicating objects and then boolean subtracting them is good--perhaps you just tried too many objects at once?

Do you use MEL at all? It is probably going to offer the most efficient solution to the problem.

The other crazy idea that comes to mind is: you could create a texture map which you use to displace the surface where the holes should be. Then convert displacement to polys and use a boolean operation to carve away those displaced parts, leaving holes behind... I don't know if that has any chance of success or not, but it might be worth a try if you're looking for randomly-spaced holes.

Good luck!

-Steve

 Re: Pattern On Surface, Repeating certain pattern on a given Surface.on Mar 24, 2008 at 9:51:28 pm

I'm looking for a rhomboid-like pattern. So this option with extruding grid fails.

I tried difference (booleans-difference operation) with one and several combined polygons (patterns). It's interesting, that when I difference with just one poly and Sphere it's working, but when I combine several polygons, and use boolean-difference option, everything disappear (sphere and combined polygons).

I didn't use MEL at all, I'll try with it. I'll also test your last idea. I hope something will work..

Thanks again for help.
Lea

 Re: Pattern On Surface, Repeating certain pattern on a given Surface.on Mar 25, 2008 at 8:42:44 pm

Do you delete history after combining the polygons for the subtraction, before attempting the Boolean? Sometimes history nodes can cause empty results like you're getting.

One other question is, do you want your final object to be hollow, like a whiffle ball, or solid, like a golf ball?

-Steve

 Re: Pattern On Surface, Repeating certain pattern on a given Surface.on Mar 27, 2008 at 7:40:30 am

I tried both ways, but I always get the same result.

I need hollow object.
Because of that, I was thinking if maybe a solution could be modeling with surfaces and curves?

 Re: Pattern On Surface, Repeating certain pattern on a given Surface.on Mar 28, 2008 at 2:35:43 am

Hmm. There's no reason in principle why the boolean difference shouldn't work. But do you really need 20,000 holes? That makes for a very complex object and that's probably what's causing the operation to fail.

One thing you could do is model only half (or a quarter, or an eighth) of your finished object to start with. That will help cut down on geometry. Another step might be to try only booleaning a smaller number of shapes at a time--again, I think 20,000 is probably far too many for the computer to handle at once.

All this being said, do you REALLY need to model this? Could a texture map for transparency not be used instead? You could use real geometry for any section that's going to be used in close-up, but rely on a texture map in the distance. That might be the most efficient way to do it.

-Steve