Author Topic: Tracing Edges of Surface Files  (Read 1641 times)

Offline Tool-n-Around

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Tracing Edges of Surface Files
« on: December 08, 2022, 17:21:48 pm »
Is there a CB function for detecting and creating lines/shapes from the edges of surface files? Sometime ago a made this part from a surface file I was given and used the polylines above the surface as bounding regions but I'll be darned if I can remember how I generated them. I did a very similar part yesterday.

To produce the bounding regions I enlarged, hand placed a lot of points along the edges looking down on the surface in XY plane, connected the points with a spline, converted the spline to polylines, and joined up the shape. It worked but was laborious and messy. When I looked at the XZ plane, many of the points I selected on the edge of the surface were assign a Z value, not 0. I had to go into the point table, change all the Z values to 0, and reconstruct the spline and polylines.

I looked at the plug-ins page but didnt see an applicable PI. Is there a better way?

Best,
Kelly

Offline Bob La Londe

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Re: Tracing Edges of Surface Files
« Reply #1 on: December 08, 2022, 18:56:43 pm »
Edit surface silhouette, or edit surface edge detect.

It's not always ideal, but you can usually get something you can work with.

Also there is a non planar parting line plugin that can be useful for some types of operations. I may be the only user to ever use it other than the writer, but it can get you there sometimes.
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Offline Bob La Londe

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Re: Tracing Edges of Surface Files
« Reply #2 on: December 08, 2022, 18:59:54 pm »
Sometimes I found the only answer is to do something similar to what you did. Zoom in and laboriously draw your own lines. When you are snapping to points they will snap to the points no matter where they are in the z-axis. If you want to use them for guidelines of some sort you can select polyline and then go edit flatten.  I don't remember if flatten is built into the edit menu or if it's a plug-in modification.
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Offline Tool-n-Around

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Re: Tracing Edges of Surface Files
« Reply #3 on: December 08, 2022, 23:13:49 pm »
Thanks Bob,

I forgot to look under Surface menu (doh!) and flatten would come in handy for the manual method with curve fitting to points. If it's something I've modeled myself, I can generate the bounding regions from my CAD program but when I'm given an .stl, I cannot.

Best,
Kelly

Offline Bob La Londe

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Re: Tracing Edges of Surface Files
« Reply #4 on: December 08, 2022, 23:33:30 pm »
No problem.  Sometimes I find myself thinking, "I know the darn tool is here somewhere.  I just can't remember where."   ;D
Getting started on CNC?  In or passing through my area?
If I have the time I'll be glad to show you a little in my shop. 

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