Question for the Metal Art guys using AutoCad

[JustAGuy]

I have been using Inkscape to start my "art work" and then taking it over to AutoCad to do the editing, after a week of studying and inching my way through things I have finally been able to clean up the cuts, join the poly lines, and smooth everything out. Now everything is fine until I load the file into my cam software, at that point the cam software will start my lead-ins over the art work lines or from the outside in. Say for instance I needed to cut the middle of the letter "O" out, the cam software starts the lead in on the outside of the letter. This is only a problem with the files that I build which tells me there is something I am doing wrong in AutoCad but I can not for the life of me figure out what. My cut paths are good, its just the lead-ins that are bad. Could really use some help on this if anyone knows the answer.

[djreiswig]

I use SheetCam, and if the path is open or there are overlapping lines it gets confused and will mix up the inside and outside cuts and put the leads on the wrong side.

[JustAGuy]

I use SheetCam, and if the path is open or there are overlapping lines it gets confused and will mix up the inside and outside cuts and put the leads on the wrong side.

I can see how that would cause a problem, I am reasonably certain that I have all my paths closed and no overlaps. It seem to be an easy thing to check with every application besides autocad.

[djreiswig]

SheetCam has a button to show the path ends. It puts a little white dot on each one. It's easy to see where the problem is if there is a dot on what should be a closed path. Either it isn't closed, or there is an extra line segment under the path. Does Coreo have this feature?

[JustAGuy]

SheetCam has a button to show the path ends. It puts a little white dot on each one. It's easy to see where the problem is if there is a dot on what should be a closed path. Either it isn't closed, or there is an extra line segment under the path. Does Coreo have this feature?

Not that I am aware of, but then again I am a new user. Autocad on the other hand, when I build/edit my files I can make sure my objects are closed.

[djreiswig]

But sometimes you can have an extra line buried and not see or select it.

[scn64]

I have been using ACAD and Draftsight for years to generate geometry for CNC machines and dealing with broken and overlapping nodes has always been an issue. It is true that certain programming software packages have the ability to detect these errors but many are expensive and in many cases are not an option for small business or home use (my current SigmaNest software is in excess of 15K) Because of this I have developed ways to check these items with low/no cost methods depending on where I am working.

You may want to look at the post I sent awhile back on generating polylines using the free ACAD clone Drafsight to get a good idea on fixing dxf geometry for use with cnc programming

Draftsight - Convert splines to polylines? https://www.plasmaspider.com/viewtopic.php?t=24723

A quick method to check your geometry for open or overlapping nodes is to fill it with a solid hatch. If the geometry is closed correctly it should be filled as intended. Below is a basic example for you to review and try.

1) I drew 2 closed circles to represent a 0 - notice the nodes and lines appear to be closed as proper geometry

closed geometry-nodes.PNG (5.87 KiB) Viewed 2892 times

closed geometry-nodes.PNG (5.87 KiB) Viewed 2892 times

2) Window the whole object and apply a solid hatch to the geometry. If the items are closed as intended it should fill correctly

closed geometry-hatch fill.PNG (7.75 KiB) Viewed 2892 times

closed geometry-hatch fill.PNG (7.75 KiB) Viewed 2892 times

Now I broke the inner circle by only .001" - Notice how the nodes appear to be correct in the full screen view even though there is a gap

open geometry-nodes.PNG (7.65 KiB) Viewed 2892 times

open geometry-nodes.PNG (7.65 KiB) Viewed 2892 times

open geometry-.001 gap.PNG (2.71 KiB) Viewed 2892 times

open geometry-.001 gap.PNG (2.71 KiB) Viewed 2892 times

When applying the solid hatch the end result is this - Obviously not what we want

open geometry-hatch fill.PNG (2.5 KiB) Viewed 2892 times

open geometry-hatch fill.PNG (2.5 KiB) Viewed 2892 times

Duplicate lines, open geometry, crossed ends, etc can be a real PIA. Especially when converting text objects. The more tools you have in your bag of tricks the better you will become at working with all types of problems. I have had to develop many methods out of necessity to do my job over the years. Take time to practice and utilize the web for all it's worth. I have become a better programmer for it and you will too

Good luck

[djreiswig]

Interesting to note that in the full screen view the circle with the gap is missing the left and right quadrant points.

[JustAGuy]

I have been using ACAD and Draftsight for years to generate geometry for CNC machines and dealing with broken and overlapping nodes has always been an issue. It is true that certain programming software packages have the ability to detect these errors but many are expensive and in many cases are not an option for small business or home use (my current SigmaNest software is in excess of 15K) Because of this I have developed ways to check these items with low/no cost methods depending on where I am working.

You may want to look at the post I sent awhile back on generating polylines using the free ACAD clone Drafsight to get a good idea on fixing dxf geometry for use with cnc programming

Draftsight - Convert splines to polylines? https://www.plasmaspider.com/viewtopic.php?t=24723

A quick method to check your geometry for open or overlapping nodes is to fill it with a solid hatch. If the geometry is closed correctly it should be filled as intended. Below is a basic example for you to review and try.

1) I drew 2 closed circles to represent a 0 - notice the nodes and lines appear to be closed as proper geometry

closed geometry-nodes.PNG


2) Window the whole object and apply a solid hatch to the geometry. If the items are closed as intended it should fill correctly

closed geometry-hatch fill.PNG


Now I broke the inner circle by only .001" - Notice how the nodes appear to be correct in the full screen view even though there is a gap
open geometry-nodes.PNG
open geometry-.001 gap.PNG

When applying the solid hatch the end result is this - Obviously not what we want
open geometry-hatch fill.PNG

Duplicate lines, open geometry, crossed ends, etc can be a real PIA. Especially when converting text objects. The more tools you have in your bag of tricks the better you will become at working with all types of problems. I have had to develop many methods out of necessity to do my job over the years. Take time to practice and utilize the web for all it's worth. I have become a better programmer for it and you will too

Good luck

I have draftsight on my office computer, so I will be able to try this to see if that is the problem. AutoCAD also has hatch functions which I have not used yet but will be trying today. Thank you for this valuable information and for taking the time to post it up.

[tnbndr]

In Autocad if you modify and change everything to Polylines, with Modify/Polyline/Join. Select objects you want to check, then right click and choose properties if set up that way or from the menu select modify, properties. At the top window verify that what you have selected are polylines, then scroll to the bottom under Misc it will say closed and the box on the right will say yes or no. If no, change to yes and it will become a closed entity.
Also there is a command in Autocad, not sure about Draftsight called "overkill" which will go through a selection and delete duplicates. Play with it on a created scenario but I check all the boxes in the dialog box that pops up.

[JustAGuy]

In Autocad if you modify and change everything to Polylines, with Modify/Polyline/Join. Select objects you want to check, then right click and choose properties if set up that way or from the menu select modify, properties. At the top window verify that what you have selected are polylines, then scroll to the bottom under Misc it will say closed and the box on the right will say yes or no. If no, change to yes and it will become a closed entity.
Also there is a command in Autocad, not sure about Draftsight called "overkill" which will go through a selection and delete duplicates. Play with it on a created scenario but I check all the boxes in the dialog box that pops up.

Not sure I follow you, I know how to join the lines but the process to modify and change to a closed entity confuses me.

[tnbndr]

I know how to join the lines but the process to modify and change to a closed entity confuses me.

It's really just a quick check for me. If you have used the modify/polyline/join command they should be good but sometimes things happen.
So when I am all done and have put all entities on their layers. I window everything or select them if have entities that are not closed polylines like cirlces, arcs, or just single line polylines. Then right click on mouse, choose Properties and in the dialog box that pops up, near the bottom it will have Misc, and one line says Closed and to the right you can click on the arrow and select yes, so it is recognized as a closed entity. In pics, see the second line from bottom in all for your selection. Hope this makes sense.

Right Click.JPG (46.01 KiB) Viewed 2832 times

Right Click.JPG (46.01 KiB) Viewed 2832 times

Properties.JPG (69.37 KiB) Viewed 2832 times

Properties.JPG (69.37 KiB) Viewed 2832 times

Properties Yes.JPG (69.03 KiB) Viewed 2832 times

Properties Yes.JPG (69.03 KiB) Viewed 2832 times

[JustAGuy]

I know how to join the lines but the process to modify and change to a closed entity confuses me.

It's really just a quick check for me. If you have used the modify/polyline/join command they should be good but sometimes things happen.
So when I am all done and have put all entities on their layers. I window everything or select them if have entities that are not closed polylines like cirlces, arcs, or just single line polylines. Then right click on mouse, choose Properties and in the dialog box that pops up, near the bottom it will have Misc, and one line says Closed and to the right you can click on the arrow and select yes, so it is recognized as a closed entity. In pics, see the second line from bottom in all for your selection. Hope this makes sense.

Right Click.JPGProperties.JPGProperties Yes.JPG

Perfect, thank you for the explanation!

[marcnaz]

Sheetcam makes it all pretty simple. I also do a lot of my basic cad work with Autocad. In case you've never used it there is a command in Autocad "OVERKILL" It will remove duplicate or overlapping lines, arcs, and polylines which may be the issue?