Connecting multiple lines into single object

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drmacro
Posts: 3348
Joined: Sun Mar 02, 2014 4:35 pm

Re: Connecting multiple lines into single object

Postby drmacro » Thu Apr 29, 2021 1:13 pm

degarb wrote: Wed Apr 28, 2021 8:26 pm In 19 isnt there a single tool to do this yet?

I am trying to get a cnc router of my drawing, but he needs a single object, 2d. I haven't plans to use 3d at this time.
There is no tool because neither he nor you understand what you are asking. Sorry, if that's too blunt... :(

DXF files DO NOT have single objects. Each line, circle, arc, etc. ARE discrete entries.

If you look at the attached files, you will find a tombstone shaped outline.

In -1, you will see a simple sketch. I have attached the dxf export of this file.
The dxf file contains 1 polyline made up of 3 lines and an arc.

In -2 you will see I added a hole. The dxf export file has 2 dxf entities; a polyline (as before, containing 4 entities) and a circle.

Note I use the word entities, this is AutoDesk nomenclature. About the DXF ENTITIES Section
This is valid dxf, per the AutoDesk dxf standard.
Attachments
Snip macro screenshot-d06d64.png
Snip macro screenshot-d06d64.png (205.41 KiB) Viewed 218 times
degarb-2-BodySketch.dxf
(1.22 KiB) Downloaded 4 times
degarb-2.FCStd
(10.19 KiB) Downloaded 5 times
degarb-1-BodySketch.dxf
(1.01 KiB) Downloaded 4 times
degarb-1.FCStd
(10.07 KiB) Downloaded 1 time
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."

My beginners, written treatise: Learning FreeCAD
degarb
Posts: 58
Joined: Fri Apr 16, 2021 7:49 pm

Re: Connecting multiple lines into single object

Postby degarb » Sat May 08, 2021 10:21 pm

What is odd, is that every company that I have been trying to get to cut my cad drawing have a different story. Some need borders, some need borders around various parts, some don't know how to import to scale. CNC router, CNC plasma cutter, Laser cutter, water jet, seem to be my options.

The sign guy didn't have a blade sharp enough for 8th inch aluminum, so he did a template in wood on his cnc. He took a screenshot of my cad file, scaled it up to size, and cut that. I used it to cut the two sidewalls. Then, I joined a maker space and did the metal bending, nearly breaking their machine. So, I am now needing to learn welding for a hydrolic press break build. In retrospect, a plasma torch and jig might be better, as the router method was torcher... Anyway the sign guy, at least would communicate, and is a college dropout. While the machine shops seems like C student trade high school grads, and I must go through old salesmen who don't understand the cam software and are past retirement age--So, I don't know what I am supposed to do to make it easier for them. Obviously, I do not want to waste space and get as much out hardware out of a 4x4 shape. So, space between parts and borders will mean doubling the cost per unit.... The sign guy was the first to pull through, and I got my prototype of metal made, minus the pinky tip that got caught in the poorly designed router.

The non profit maker space used Aspire 2.5 for designing things and mach3 for running the machines. But their cnc router and cnc plasma cutter are both down. And their tech guy has yet to learn mach3, but is extremely bright.

The prototype has forced me to make a weeks worth of changes. I have periodically been trying to take my shape and make it a sketch, after extensive reading. Simple proto drawings seems to work, but my complex part hasn't seemed to work. Yeah, I selected all lines, arcs, notches, circles of the part, and did the Draft to sketch, THen I went to sketcher, then did validate sketch, set to .1, Then I take it to part and extrude, but it says my lines aren't closed yet, which they are. I try to look at the extrude and sketch, but it looks blank, although the validate supposedly fixed 23 coincidences.

What is weird, is that I hear what you are saying, but the one Union machine shop (4x the price), supposedly cleaned up my dfx, and sent it back to me. When I opened his dfx, he had somehow created dxf that was all connected. It was only when I exported his dfx and imported it that I got my a bunch of shapes for each line.

Most of the 3d printing people are doing seems to be stl files using thingaverse and tinkercad. I don't yet see the need to jump to different software. Freecad is buggy and weird, but most of the tools seems to work. For example the arc tool worked the minute I installed it, while I gave up on libre cad after trying to make an arc for 20 minutes, then I gave it to my teens, who couldn't figure out an arc in the next half hour. I didn't bother further, because if they can't make an arc tool intuitive, they are too underfunded to waste time using that program. Freecad does just find in 2d drafting, minus the times I need to kill the program to get my ability to clone, move, use a centered grid, etc. At least on windows.
drmacro
Posts: 3348
Joined: Sun Mar 02, 2014 4:35 pm

Re: Connecting multiple lines into single object

Postby drmacro » Sun May 09, 2021 12:32 am

Interesting, I haven't used LibreCAD for a project in some time, I don't remember the arc command being anything odd...start the command and click 3 points.🤔

But back to dxf.

"he fixed it up" is pretty nebulous. It sounds like he make whatever was in the file into polylines. Then whatever import preferences you have set imported them as polylines, but when you exported them they got broken into their constituent parts.

In any case, without a simple example, (like the example I posted) a version of the dxf file having been produced by your contractor the way he needs/wants it and the same geometry the way FreeCAD creates it to allow side by side comparison of what's actually in the two files, figuring it out is a guessing game.

As for you missing coincidences, again a guessing game. You can disable the dimensional constraints and try to move the lines of the sketch. I'm guessing, one, or more, of them will pull apart.
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."

My beginners, written treatise: Learning FreeCAD
Bance
Posts: 1947
Joined: Wed Feb 11, 2015 3:00 pm
Location: London

Re: Connecting multiple lines into single object

Postby Bance » Sun May 09, 2021 7:59 am

He's not figured out how to sketch yet..... ;)

Its still draft.