Can you model a surface based off 3D datum curve making up the boundary (not 2D)?

[LawrenceS]

More specifically, I am trying to better understand how to fix broken imported models (IDD, surfacing, etc), and cannot figure out a way to just close a series of surfaces that make a clear and definite shape.  The fill command seems only to work with 2D sketches.  Same with Extrude.

I have attached an example of a closed boundary curve that I would like to know how to make into a surface.  Any ideas?

Thanks!

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[JonathanHodgson]

Boundary Blend is sometimes useful in patching broken imports, but it needs the bounding curve to be split into at least two opposite sides, and ideally four I think.  I'm not an expert in making it work though!

[LawrenceS]

Thanks for giving it a crack.   I actually tried it with the fill command but didn't work how I hoped since a 2D sketch is just 2D and this curve is actually in 3D.  When I tried I used 3 points to create a datum and then a sketch over that, however when I zoom in close all the edges are not aligned with the actual curve.  If you did get this to work, can you post the results?

[MarkMcDonald · Accepted solution]

Lawrence,

Here is my take on how to surface your geometry.  Creo 2 model is attached.  Basic method was:

• create datum curve to close the notch
• 4-sided boundary surface
• extruded cut to create notch

[LawrenceS]

Mark McDonald‌, thanks for the tip and attaching the file!  That is clever, and works for this surface.  Thanks again for your help!

Correct me if I am wrong, but what I am gathering from this is that the boundary blend can really only be used if there are a definitive of 2 or 4 (or more, or possibly 3) continuous edges without much meandering.  So even though the desired feature could be enclosed by a datum curve, there is not a way to get the boundary blend to do this as one enclosed 3D surface, nor is there a way to use the fill feature on anything but a 2D sketch.

It sure seems to me that these surfacing is way more complicated than it should be.  I don't know why there is not the option to just do a 3D enclosure, and then be able to tweak it by grabbing the surface anywhere, or an edge/vertex and then either move/align it to a new constrained location or by a dimension.  This IDD stuff would be a lot easier and more intuitive if I could do it that way...unless I am just missing something huge.

[MarkMcDonald]

Yes, a boundary blend surface works best with two or four bounding curves and the resulting surface is generally better when the bounding curves don't have abrupt changes in direction.  And yes, the "fill" command will only create a planar surface.

I agree about IDD being less than intuitive.  My experience with it has been very hit-and-miss.  Sometimes I can get it to automatically close gaps and repair the surfaces.  But most of the time, I end up manually patching bad or missing surfaces with a boundary blend.

[LawrenceS]

I could almost never get the boundary blend to work until I saw a video instruction on how to use the shift key to select a series of long edges to get one side...wish I could find something so useful to get it to work in other situations too! 😉  A 3D fill would be awesome...especially if it is actually available in IDD (strange that the 2D fill is not available there!)!

[dguillette-2]

Hi Lawrence, been watching this thread and just wanted to chime in. As with all things ptc, there are always many ways to skin the cat.

If the surface is MIA the info you received is all good stuff. I have found surfaces like this may be easier to create outside of IDD (see the attached zip). Note the curve copies are "approximate" and not "exact". Used the collapse geometry tool found under edit in the model tab to merge the new quilt into the import feature.

If there was a broken surface attached to the curves in your sample upload you may want to try this.

detach the problem surface

select one of the edges of the surface with a left click

right mouse down and select delete

the surface will now be a rectangular sheet at the loops extreme.

IDD is a very powerful tool and the ptc tutorial is just the tip of the iceberg.

I have found working with a copy in an assembly is the safest way to achieve good results and be sure the design intent was not lost.