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Surface generation question....

Bwts

New member
I have two curves, one is a closed loop, the is open. I have guide lines from one curve to the other.


My question is how to I generate a surface between the curves? I can use boundary surface if both curves are closed or both are open but not if I have one of each





Thanks Nic
Edited by: Bwts
 
Is it possible for you to add a picture about the subject? As far as I know, it is not possible to loft a closed profile/curve with an open curve.


To work around this in an easy way, just split the closedcurve into 2 opencurves and use guide curves to define the shape. You can draw all of this just in 1 3d sketch and use that sketch for both the 1st and 2nd loft.While lofting the 2nd curve, the 1st time you select the (originally) open curve, you need to select it twice because it is allready consumed by the 1st loft.It is possible that the same issue willappearwith the guide curves.
Edited by: Raoul-RW
 
Bwts,


More heart valve modelling? How do you want it to look when you're done? I mean, do you want to fill in the gap in the profile with two curves? If so, just add a spline between the two (best guess) and now you have two closed loops.


Otherwise, you can split that closed loop (there are a few ways to do this in SW) but then you'll have a gap in your final surface.


Such is the case when you have missing data in your curves... you either fill it in with a best guess or you have a gap in your surface...


Make sense?


Jim
http://www.linkedin.com/in/shawengineering
 
Bwts,


Also, not sure if you meant to do this or not, but I noticed that there seems to be no tengency or curvature continuity between your surfaces. If you are trying to make an accurate surface model from a series of "slices", you'll prob want to add both of these constraints. Are you familiar with this method?


Jim
http://www.linkedin.com/in/shawengineering
 
Hi Jim,


Yep more hearts. The surface does split into two surfaces, so it isnt a matter of missing data its supposed to do that.


I'm not familiar with the tangencey/ curvature conatrainst.





Bwts
 
Bwts,


Ah, yes, this is for the start of the opening of the valve, right? Then, you need to split the closed loop into two curves. You can create a 3D sketch, select thatedge (or even better, the original curve itself), and select Tools>Sketch Tools>Convert Entities. Another way is to select Tools>Spline Tools>Fit Spline. I believe either will work in your case.


Once you have the entity in your sketch, you can just draw a construction line and use it to split the curve into two parts. Finally, create the two separate surfaces.


For tangency/curvature, you'll need to create each surface as a boundary surface. This will be tough to explain in detail with words, so if you want, you can forward me the geometry andI will show you.


Jim
http://www.linkedin.com/in/shawengineering
 
Hi Jim,


I have been using boundary surfaces with guides between the contours. My problem is that if I break a contour curve then the boudary surface above then disappers.


Bwts
 
Bwts,


Then you're not doing it the right way.
smiley2.gif



You need to essentially copy the single contour to a new contour, then split that new contour into two parts. This way, the original contour is not affected at all. There are multiple ways to do this, I have suggested two: "convert entities" and "fit spline", both from within a new 3dSketch. Make sense?


Jim
http://www.linkedin.com/in/shawengineering
 

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