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 From:  Marc (TELLIER)
1808.1 
Hi,

I can't get to subtract the longitude and latitude lines from the sphere.
I have also tried union and it does not work.

Something I am doing Wrong or that I don't understand about the lore of nurbs?

Regards,

Marc

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 From:  Michael Gibson
1808.2 In reply to 1808.1 
Hi Marc, this seems to be a popular shape recently!

It can be pretty tough for the boolean code to handle shapes that criss-cross and barely graze each other, and the more added the more complex things get. It's especially a problem with curved type surfaces rather than straight ones, because the curved ones tend to end up with a lot of little tiny slivers where they cut though each other just barely.

Please check out Danny's message here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=1792.12

for an alternate construction method that will be much more reliable for building this shape.

- Michael
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 From:  Marc (TELLIER)
1808.3 In reply to 1808.2 
Thanks for the quick reply Michael, this seems like a good solution!

Marc
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 From:  Michael Gibson
1808.4 In reply to 1808.3 
Hi Marc, also another alternative way is the following.

First I drew a circle in the Top view, and used that in a boolean to cut the latitude tubes, so that they were separate and not all overlapping each other at the poles:



Now that will avoid one area that confuses the booleans and those can be booleaned away from the sphere body:



The result model of that is attached here as "2008-07-23 - Globe_2.zip".

Now the latitude lines have the same kind of difficult area where they are touching the longitude ones at a kind of single crown point type thing, that is an area that is not currently handled well.

If you re-create those latitude lines using a slightly smaller or larger radius than the longitude ones, then those should carve out better.

But definitely that other method of building just one slice and replicating it will tend to avoid criss-cross pieces even more and probably work better.

- Michael

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 From:  Frenchy Pilou (PILOU)
1808.5 
With the first model all latitudes works fine one by one
It's the longitudes who makes problem

Of course it is a more tricky way to make first a slicer part then mirror it ;)
Less computation inside!

EDITED: 23 Jul 2008 by PILOU

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 From:  Marc (TELLIER)
1808.6 In reply to 1808.4 
Hi Michael,

""If you re-create those latitude lines using a slightly smaller or larger radius than the longitude ones, then those should carve out better.""

I am pretty sure this would have worked, I did not thought of this solution.

Well, I've managed to do it with the section method. Although I was not able to Union the parts afterward it will do the job for now.

Thanks again!

Marc
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 From:  Michael Gibson
1808.7 In reply to 1808.6 
You're welcome Marc!

Re: union issue - one thing you can do if union is getting confused at the overlapping pieces is to delete the side pieces for your segment so that your segment is just a surface (or possibly a set of joined surfaces) instead of a solid.

Then replicate your segment, and you will have a set of surfaces that touch each other precisely edge-to-edge.

In that kind of situation you can then use Edit/Join to glue the surface pieces together into a solid.

Join can be more reliable in situations like that because it does not try to find any intersections between the pieces, it only tries to glue edges together and not remove material or create new edges by surface/surface intersection.

Trying to get clean intersections between pieces that overlap tends to be a difficult area of calculation.

You do need to have the pieces have a pretty precise alignment with one another for the join method to work though.

- Michael
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 From:  Marc (TELLIER)
1808.8 
Great, I did not know of the "join" technique, I will try it!

Marc
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