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Adding points and lines to 3D models with parametric surfaces
Posted 16 mai 2013, 10:35 UTC−4 Geometry, Parameters, Variables, & Functions, Results & Visualization, Structural Mechanics Version 4.3b 7 Replies
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I was wondering if there is a way to add a point or line to a model in which I have a 3D block with the top surface replaced by a parametric surface derived from a DEM (digital elevation model).
I guess this can be done in either the geometry section so it is there for the entire model run, or in the results section under data sets.
The end result I am after is the displacements along a line that traverses the parametric surface or at a certain point on the parametric surface.
Any help in this matter would be greatly appreciated, and let me know if I haven't explained the problem sufficiently.
Thank in advance!
James.
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If all you are looking to do is post-process, then I would suggest using the "Surface" Data Set. Right-click on Data Sets and select Surface. This creates a 2D data set of your parametric surface.
Or, you could also do a Parameterized Curve 3D (under More Data Sets) where you can define a path in 3D. Or, take Cut Point 3D to take data from a general point.
These lower dimension subsets of the original 3D data sets can then be plotted, operated on, evaluated, and/or exported.
Best regards,
Josh Thomas
AltaSim Technologies
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Thanks! That worked very well!
Eventually I also need to be able to add points to the geometry before I run the model. Do you know a way to do this? I can't just add a point in the regular way as I don't know the exact Z-coordinate to place it directly on the parametric surface. I thought I might be able to define the z-coordinate with 'ps1' (for the parametric surface) instead of a number but it obviously didn't work. Is there a similar way around it?
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Here is a way to do it. Under the Geometry, you can define a parametric curve that is a vertical line (no variation in the z-dir) that intersects the parametric surface at the correct x,y location. Then, use the new partition Boolean functionality to create a point at the intersection. In this way, you don't have to know the exact z-location. COMSOL will calculate it for you.
Be sure to click on the "Select Points" filter icon at the top of the Graphics window to visualize that indeed a point has been created on the surface.
See attached *.mph file. And, screenshot.
Best regards,
Josh Thomas
AltaSim Technologies
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Thanks again. I tried a similar technique with a line and then deleting entities. This partition tool seems to do the same thing. It works in that it creates a point on the surface in the correct place. However it also impedes the interpolation of the parametric surface in the immediate area. I've attached a screen shot to show what I mean.
Do you know a way around this?
Cheers!
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Hmmm.... the only thing I can think of is adjusting the "Relative repair tolerance" on the Partition Boolean operation settings window. Judging by the screenshot you sent over, I'd suggest reducing this value although you could try both increasing and decreasing and see what happens.
I'm interested to know how it goes.
-Josh
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I've sent a request to COMSOL support so hopefully they'll come up with something smart.
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