lisp for creating slot from polyline centerline

[KCorby]

I am looking for a routine that will ask to select a centerline (multi-section polyline which includes arcs), then slot width, and generate a slot based on the centerline. My drawing sequence for this includes offseting the centerline to both sides, then using FILLET to draw the radii on the ends, then deleting the centerline. I would like the resulting slot to be a closed polyline if possible. Any help would be greatly appreciated!

[paulmcz]

Another approach would be that after you get the width, length and center point of your slot from the user prompts, calculate the four points position and feed them to the polyline command. No need for offset or erase and you end up with closed polyline slot.

[KCorby]

Another approach would be that after you get the width, length and center point of your slot from the user prompts, calculate the four points position and feed them to the polyline command. No need for offset or erase and you end up with closed polyline slot.

 

Thanks for this suggestion. But my slots are often more than just straight slots. They will sometimes have a "bend" in the middle (think of a slot that looks like the letter "L" or "S"), which is why I am using the method of offsetting a centerline to manually draw it. I think inputting the points is too cumbesome based on the more complicated centerline shapes.

 

Also, I forgot to mention in my origional post the step of exploding the offset polylines so that I can use the fillet command to close them.

 

Some more background - what I am doing here is designing "break away tabs" in a PC board that has an irregular outline. Therefore the machine shop will route away most of the material along the edge of the PC board, leaving small tabs that will be cut manually after the next higher assembly in order to depanel the board. I am drawing the router path.

[paulmcz]

Sorry I didn't get that from your first post.

The same method I described for the straight slot can be applied for your case but it is far more complicated. You can extract all the polyline points, including arc points and calculate all the points of your slot outline for the polyline. It is a lot of work but if you do this very often, it might be worth the effort.

[Lee Mac]

This should get you part-way there, or at least reduce some of the time:

 

http://lee-mac.com/doubleoffset.html

[BlackBox]

You may want to consider using the vlax-Curve-* functions, which will work with eName, or vla-Object.

[mdbdesign]

Multiline will work for you?

 

[KCorby]

Multiline will work for you?

 

[ATTACH=CONFIG]34233[/ATTACH]

 

I did experiment with multiline, but it is limited to not being able to follow a path that contains arcs. Here is an example of what I would like my end result to resemble.

 

[mdbdesign]

Yes, multiline is not doing arc's.

Try Lee double offset and fillet "0" ends.

[KCorby]

Yes, multiline is not doing arc's.

Try Lee double offset and fillet "0" ends.

 

Yes, that would work, but it is not saving me as much time as I would have hoped for. If I could figure out how to modify the lisp that Lee provided to get it to draw the closed ends, that would be perfect. Using the function RenderMan mentions in addition to Lee's routine may do it, but I do not know how to work with the vla functions, so it may take me quite a bit of time to research. Thanks for the input!

[Lee Mac]

Hi KCorby,

 

Since you have fewer than 10 posts, I cannot send you a PM, but I would be happy to write a program for you that would prompt for selection of multiple LWPolylines and produce the required result in one step, if you are interested, send me a message through my site and we can discuss it further.

 

Cheers,

 

Lee