CAD/CAM discussion forum > Other CAD/CAM Technology > How do I check if a sketch is "closed"?

How do I check if a sketch is "closed"?

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OldForumPost

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Message 1 of 14

 How do I check if a sketch is "closed"?
10-02-2006 09:29 . pm | View his/her posts only
In the 2D Sketcher, does VX have a function to check if a sketch is "closed" or will be able to form a good solid? Or perhaps this function can tell me where the sketch has gaps or is overlapping.

For example:
I make a medium complity sketch and I try to extrude it. I may get an error."Offset curve intersections, possible bad geometry."
I then go into the sketch and try to zoom into areas where there may be tiny gaps or overlaps at line intersections.
This can get very time consuming for even a simple sketch.

Thanks!

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OldForumPost

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Message 2 of 14

10-02-2006 09:38 . pm | View his/her posts only
After a little poking around in the sketcher menus I found what I was looking for.
It is under "Inquire", and it is called "Show Gaps".

Thanks!

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ChrisWard2k2

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Message 3 of 14

13-02-2006 04:10 . pm | View his/her posts only
Hi Clinton

That is indeed the first tool to reach for. Just to let everyone else know that it will also find overlaps, not just gaps.

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george

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Message 4 of 14

13-02-2006 09:18 . pm | View his/her posts only
VX should use whatever is in the extrude function for checking for gaps, even though show gaps does not find a problem when you try to extrude it finds a problem.

Also smaller pieces in a sketch like from referencing edges can cause headaches, try to join the smaller pieces to make a longer one.

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ChrisWard2k2

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Message 5 of 14

14-02-2006 06:14 . am | View his/her posts only
Hi gjohn

Do you have a VX file example that we can examine? VX extrude does not actually care about gaps in the profile - if there are none and you include both end caps (default), then a solid body is produced. Otherwise, an open faceset is produced. The most common problem reported to me is with DXF/DWG imported from AutoCad. AutoCad Users do not need to worry about the quality of their 2D geometry as they are not going to use it to make a 3D model. Consequently, the geom is often poor - overlaps and duplicate entities (or near-duplicates) being the most obvious faults, but you also see poor tangency on filleted corners and "polylines" used where pure lines and arcs would be better (VX can convert them). Applying VX dimensions and constraints automatically is a quick way to reveal most problems of this kind.

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george

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Message 6 of 14

14-02-2006 07:08 . am | View his/her posts only
Since we are talking about sketches I will mention this even though it is a cam issue. If there are small segment in a sketch being used as a boundry the tool path won't calc. or it will only calc part of the tool path.

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ChrisWard2k2

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Message 7 of 14

14-02-2006 11:49 . am | View his/her posts only
Hi gjohn, everyone

If anybody hits this cam problem, we would like to have the Sketch so that we can see if the code can be improved.

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Paul

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Message 8 of 14

16-02-2006 10:05 . am | View his/her posts only
I was just about to submit a PCR for this issue and I see that my fellow worker George has been suffering the same problem.

I will submit a sketch to this forum post to show what George is talking about. I won't submit the PCR just yet, but this indeed is a pain.

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Paul

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Message 9 of 14

16-02-2006 10:12 . am | View his/her posts only
What's the trick behind getting this to show up as an actual VX file. My attachment shows up as Heiroglyphics or Wing Dings.

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ChrisWard2k2

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Message 10 of 14

16-02-2006 06:05 . pm | View his/her posts only
Hi Paulverisor

It is an actual VX file but the name and file ext gets changed. Right-mouse click Save Target, the edit the name and extension once the file is saved to your drive. It is probably best to upload VX files as a zip or rar file. Thanks for the Sketch.

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ChrisWard2k2

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Message 11 of 14

16-02-2006 06:38 . pm | View his/her posts only
Hi again

Well, Murphy's law comes into play. I have used your Sketch to define a pocket in a simple rectangular base model, and in the CamPlan I have added it as a containment for a QM Z level op - everything works perfectly in VX v11.60. If I change the computational tolerance of the model from 0.01mm (default) to 0.001mm, the extruded cut fails, so make sure that you have a reasonable tolerance. Is there a particular CAM op that fails with this Sketch?

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george

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Message 12 of 14

16-02-2006 07:23 . pm | View his/her posts only
Offset 3d finishing

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ChrisWard2k2

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Message 13 of 14

17-02-2006 05:13 . pm | View his/her posts only
Hi again gjohn

Well, offset3Dfinish would not necessarily be a good choice in my example where the shape is a pocket, but none-the-less it calculates and verifies perfectly OK. If you have the time, could you put together a sample file where the Sketch does cause a CAM failure?

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george

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Message 14 of 14

17-02-2006 07:51 . pm | View his/her posts only
I will as soon as I can.
See also