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Cannot select geometry in physics section

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Hi,

I have a problem with a Fresnel lens like structure, I created by combining parametric curves and Bezier segments. After drawing and merging the lines, I revolved the working plane and got the wanted structure in 3D. However, while meshing and selecting boundaries to assign materials is possible, I cannot select my geometry in the "Solid Mechanics" node. I'd appreciate any ideas/suggestions...

Regards,
Simon


2 Replies Last Post 7 mar 2013, 05:38 GMT-5
Magnus Ringh COMSOL Employee

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Posted: 1 decade ago 7 mar 2013, 05:33 GMT-5
Hi,

There are a couple of issues here:

1) You are revolving a curve from the 2D work plane, creating only surfaces and no domains in the 3D geometry, so you should replace the Convert to Curve node at the end of the work plane's geometry sequence (which really doesn't make a difference) to a Convert to Solid node.

2) COMSOL will not form a solid because there are tiny gaps in the curve. This is due to rounding. For example, -(0.56258)^2 is -0.3164962564 and not -0.3165. You can form a solid anyway by increasing the relative repair tolerance in the Union node's settings to 0.0001. Perhaps a tighter tolerance can be used if the input data to the curves is adjusted to be more exact.

Best regards,
Magnus Ringh, COMSOL
Hi, There are a couple of issues here: 1) You are revolving a curve from the 2D work plane, creating only surfaces and no domains in the 3D geometry, so you should replace the Convert to Curve node at the end of the work plane's geometry sequence (which really doesn't make a difference) to a Convert to Solid node. 2) COMSOL will not form a solid because there are tiny gaps in the curve. This is due to rounding. For example, -(0.56258)^2 is -0.3164962564 and not -0.3165. You can form a solid anyway by increasing the relative repair tolerance in the Union node's settings to 0.0001. Perhaps a tighter tolerance can be used if the input data to the curves is adjusted to be more exact. Best regards, Magnus Ringh, COMSOL

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Posted: 1 decade ago 7 mar 2013, 05:38 GMT-5
OK, thats it. Thanks a lot for your help!
OK, thats it. Thanks a lot for your help!

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