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Dear Max,
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<div>Thanks for your thoughts. However, I am not sure how this helps as the spheres are no longer concentric.</div>
<div><br>
</div>
<div>I have made another example script, this time in python, that shows the issue that I keep coming up against. If you run the script, you will see that surfaces 10 and 13 have the same set of bounding curves: 6, 7, 8 and 9, but one is a bspline surface and
the other is a spherical surface. Perhaps I simply need to delete one of these?</div>
<div><br>
</div>
<div>Regards,</div>
<div><br>
</div>
<div>Peter.</div>
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<div name="messageSignatureSection"><br>
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<br style="font-size: 14px; font-family: -apple-system, BlinkMacSystemFont, sans-serif;">
Associate Professor Peter Johnston (FAustMS, FIMA)<br style="font-size: 14px; font-family: -apple-system, BlinkMacSystemFont, sans-serif;">
School of Environment and Science<br style="font-size: 14px; font-family: -apple-system, BlinkMacSystemFont, sans-serif;">
Griffith University | Nathan | QLD 4111 | Technology (N44) Room 3.19<br style="font-size: 14px; font-family: -apple-system, BlinkMacSystemFont, sans-serif;">
T +61 7 373 57748| F +61 7 373 57656 Email p.johnston@griffith.edu.au</div>
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<div name="messageReplySection" style="font-size: 14px; font-family: -apple-system, BlinkMacSystemFont, sans-serif;">
On 29 Apr 2019, 6:41 AM +1000, Max Orok <morok@mevex.com>, wrote:<br>
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<div>Hello Peter,<br>
</div>
<div><br>
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<div>I took a bit of a different approach and hopefully it is similar to what you'd like to do.<br>
</div>
<div>This short script makes a "sphere patch" by subtracting one sphere from another.<br>
</div>
<div><br>
</div>
<div><span style="font-family:monospace,monospace">SetFactory("OpenCASCADE");<br>
<br>
// arbitrary angle selections here<br>
Sphere(1) = {0, 0, 0, 0.5, -Pi/9, Pi/9, Pi/4};<br>
Sphere(2) = {-.25, 0, 0, 0.5, -Pi/9, Pi/9, Pi/4}; // shift sphere 2<br>
<br>
// use sphere 2 to cut sphere 1<br>
BooleanDifference{ Volume{1}; Delete; }{ Volume{2}; Delete; }<br>
</span></div>
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<div><img src="cid:ii_jv1ebup50" alt="image.png" width="425" height="248"><br>
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<span style="font-family:monospace,monospace"></span></div>
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<div><img src="cid:ii_jv1edatm1" alt="image.png" width="415" height="235"><br>
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<br>
I hope this is helpful! If I missed the point please let me know.<br>
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<div dir="ltr"><br>
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<div>Sincerely,<br>
</div>
<div>Max<br>
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</div>
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<br>
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<div dir="ltr" class="gmail_attr">On Wed, Apr 24, 2019 at 7:22 PM Peter Johnston <<a href="mailto:p.johnston@griffith.edu.au">p.johnston@griffith.edu.au</a>> wrote:<br>
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Thanks Max and Christophe,
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<div>I have attached a simple sample .geo file. For some reason it creates even more volumes than the more complicated script I was working on. However, it still displays similar problems.</div>
<div><br>
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<div>If you have any further questions, please let me know.</div>
<div><br>
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<div>Thanks again,</div>
<div><br>
</div>
<div>Peter.</div>
</div>
<div name="messageSignatureSection"><br>
<div class="gmail-m_4024552212881412050matchFont">---------------------------------------------------------------------<br style="font-size:14px;font-family:-apple-system,BlinkMacSystemFont,sans-serif">
<br style="font-size:14px;font-family:-apple-system,BlinkMacSystemFont,sans-serif">
Associate Professor Peter Johnston (FAustMS, FIMA)<br style="font-size:14px;font-family:-apple-system,BlinkMacSystemFont,sans-serif">
School of Environment and Science<br style="font-size:14px;font-family:-apple-system,BlinkMacSystemFont,sans-serif">
Griffith University | Nathan | QLD 4111 | Technology (N44) Room 3.19<br style="font-size:14px;font-family:-apple-system,BlinkMacSystemFont,sans-serif">
T +61 7 373 57748| F +61 7 373 57656 Email <a href="mailto:p.johnston@griffith.edu.au" target="_blank">
p.johnston@griffith.edu.au</a></div>
</div>
<div name="messageReplySection" style="font-size:14px;font-family:-apple-system,BlinkMacSystemFont,sans-serif">
On 25 Apr 2019, 1:36 AM +1000, Max Orok <<a href="mailto:morok@mevex.com" target="_blank">morok@mevex.com</a>>, wrote:<br>
<blockquote type="cite" style="margin: 5px 5px; padding-left: 10px; border-left: thin solid #3498db;">
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<div>Hi Peter,<br>
</div>
<div><br>
</div>
<div>Scripts are always helpful! It is nice to be able to see the steps as you go along.<br>
</div>
<div><br>
</div>
<div>Max<br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Wed, Apr 24, 2019 at 8:36 AM Peter Johnston <<a href="mailto:p.johnston@griffith.edu.au" target="_blank">p.johnston@griffith.edu.au</a>> wrote:<br>
</div>
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Hello,
<div><br>
</div>
<div>I appear to have a problem for which I cannot figure out a solution.</div>
<div><br>
</div>
<div>I have an annular hemispherical volume created between to hemispheres centred on the origin. I would like to divide the volume into two parts in a special way using Boolean operations. To define a sub-volume of the initial volume by defining four points
on the surface of the inner sphere, create a “quadrilateral” on the inner surface by joining the four points in order using circles through the origin. (I think that these should be parts of great circles on the inner surface?). Then I create a line loop and
a surface, and finally extrude the surface away from the origin to create a volume. Perhaps a .geo script would help here?</div>
<div><br>
</div>
<div>When I perform BooleanDifferences and BooleanIntersections I end up with three volumes instead of two. The reason I get the third volume is that the surface patch that I create does not fit exactly onto the original spherical surface. Is there any way
that I can force the patch to be part of the spherical surface?</div>
<div><br>
</div>
<div>A consequence of the extra volume is that I cannot create a sensible mesh.</div>
<div><br>
</div>
<div>Any ideas would be greatly appreciated.</div>
<div><br>
</div>
<div>Thanks very much,</div>
<div><br>
</div>
<div>Peter.</div>
<div><br>
</div>
<div>PS, I could send a simple script file if that would help.</div>
</div>
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<br style="font-size:14px;font-family:-apple-system,BlinkMacSystemFont,sans-serif">
Associate Professor Peter Johnston (FAustMS, FIMA)<br style="font-size:14px;font-family:-apple-system,BlinkMacSystemFont,sans-serif">
School of Environment and Science<br style="font-size:14px;font-family:-apple-system,BlinkMacSystemFont,sans-serif">
Griffith University | Nathan | QLD 4111 | Technology (N44) Room 3.19<br style="font-size:14px;font-family:-apple-system,BlinkMacSystemFont,sans-serif">
T +61 7 373 57748| F +61 7 373 57656 Email <a href="mailto:p.johnston@griffith.edu.au" target="_blank">
p.johnston@griffith.edu.au</a></div>
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<div>Max Orok</div>
<div>Contractor<br>
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<div dir="ltr"><a href="http://www.mevex.com" target="_blank">www.mevex.com</a><br>
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<div>Max Orok</div>
<div>Contractor<br>
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<div dir="ltr"><a href="http://www.mevex.com" target="_blank">www.mevex.com</a><br>
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