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closed datum curve on quilt

ThomasPhore
8-Gravel

closed datum curve on quilt

I would like to make a closed datum curve using the option (in "Attributes") of being a curve on a surface rather than a free curve.

However, no matter how I select my curve points, the start and end of the curve are never tangent to one another. In fact, if I try to make any closed curve, it always fails apparently because of the end conditions. If I remove the final point in the curve so it is not closed, I never have any problems generating the curve. However, any curve I create on a surface fails.

In the case of a free curve rather than a curve on a surface, one has "Tangency" options that they can define so as to make the curve a continuous loop. However, the Tangency option is not available while creating a curve on surface.

This is immensely frustrating. Anyone have any suggestions?


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9 REPLIES 9

Thomas,

This post may help a bit.http://communities.ptc.com/message/12976#12976

You can draw a closed sketch (on a flat plane) and then Edit>Project onto a surface to have the sketch fit the contours of that surface. If nothing happens once you choose the sketch and the surface to project onto, its probably because a Direction needs to be defined. I almost always use one of the axes of a coordinate system.

This solution may not work, it depends on your geometry. Can you post images and/or upload the part?

-Kevin

The surface I am puting the datum curve is too crazy to project anything onto with sufficient accuracy of intent. Here is an example of the kind of surface I am drawing on (first picture). The one I'm drawing on now is very similar but actually more difficult since it is on a larger surface of comparable "curvaceousness". I really need the precision of being able to place datum points on the surface and then have a curve that goes through them. Or at least something that achieves same effect, and I don't believe there is any method that involves projecting sketches that does.

http://communities.ptc.com/message/178703#178703

In that case, you will need an entity at the end/start point of your curve that you can apply tangency to, such as an axis or a short length of projected curve. I think the axis technique is the least attractive option here. Do you follow my meaning? I can add some images if needed.

-Kevin

Ok, I used Style to draw a tiny little COS (line on surface in this case) running through my start/end datum point. However, I do not know how to apply tangency now. The "Tangency" option in the main "Curve: Through Points" menu is not available when drawing a curve that is "Quilt/Surface" rather than "Free".

That's not the case from my side. Tangency is available with Curve Through Points and Quilt/Surface. See in the image the green arc. It's a projected sketch that I've used to define tangecy.

I can't think of why you can't use it. The menu manager options for Tangecy do don't open by default. You will have to click Tangecy and then Define.

curve-quilt-tang.PNG

-Kevin

Very interesting. Apprently the problem is that my curve is on a quilt rather than on a "surface" because after seeing your results I tried making curves just made between two points. If both points are on a common "surface" (panel that highlights when in surface selection mode), then when I select the "Attributes" to be Quilt/Surface and choose the surface panel, I get the tangency option as you do. However, with the same curve, if I select the quilt rather than individual panel, I do not get the tangency option.

ARGH!

Is it conceivable it is to make a continuous closed datum curve on a quilt? I tried taking an almost closed curve and splicing it with a COS using Style mode, but that ends of producing other issues...

Still not the same result I'm getting. My previous image is showing me placing a curve on a quilt with tangency constraints.

At this point the only difference I've seen between our techniques is that you used a Style feature to create a COS for applying tangency and I projected a curve with an endpoint coincident to the datum point that I used as the end/start of my closed datum curve and used it for tangency. I've never had the Style feature available to me so I can't comment on it.

Can you make a recording of the steps you're going through? Go to screenr.com to instantly make on screen videos. You don't have to download anything, in works from the browser.

-Kevin

Just reporting back to let people know what I ended up doing:

It turned out to be impossible to create a closed curved on a quilt made up of several surfaces. I'm not sure exactly where the line is between software bug and misleading interface design, but anyway, it appears to be impossible to create a closed curve on a quilt. The reason is that the tangency option does not appear for the ends of the curve. Therefore, when you produce a closed curve, you get a discontinuity at the start/end point, which in turn seems to render it unacceptable by proe for rendering a curve on the quilt.

The workaround I used was creating a COS in Style to close an open datum curve on the quilt. In other words, when creating the datum curve, I left out the final point that would make it close, and then instead closed it afterwards by creating a COS in Style.

I hope this gets changed in the next version of ProE! Thanks for all the help!

Thomas,

You should post this in the new "Ideas" section. You could pratically just copy what you said above and also provide a link to this thread if anyone wants to get further details to make sense of the problem you encountered.

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