Added toolpath is on the wrong side

Discussions around the CAM Add-On of QCAD.

Moderator: andrew

Post Reply
Ico
Junior Member
Posts: 11
Joined: Wed Apr 24, 2019 2:39 pm
Location: Canada

Added toolpath is on the wrong side

Post by Ico » Wed Apr 24, 2019 3:34 pm

I am using QCAD/CAM 3.22 (latest version). I have many drawings that contain several contours and they need to be cut on the inside. When i select all of the (inside cut) contours to create a new toolpath, QCAD would create the path correctly for most of them, except one or two of them which get a toolpath on the outside. Here is a sample drawing that has one of those contours. The first "o" in Robinsons always gets cut on the outside (wrong), while the second "o" gets cut on the inside (correct). The two "o" are actual copies of each other and they are exactly identical. I suspect that the other contours around the "o" are the cause of the error, because if I select the problem "o" by itself and create new toopath with exactly the same settings, it will be created correctly. I have many more drawings that behave the same way.

If anyone has any ideas as to why this happens? Any help will be a great help.
Thanks in advance!
Attachments
Robinsons (forum).dxf
(929.71 KiB) Downloaded 40 times

User avatar
Husky
Moderator/Drawing Help/Testing
Posts: 2486
Joined: Wed May 11, 2011 9:25 am
Location: USA

Re: Added toolpath is on the wrong side

Post by Husky » Wed Apr 24, 2019 7:42 pm

Ico wrote:
Wed Apr 24, 2019 3:34 pm
The two "o" are actual copies of each other and they are exactly identical.
For some reason they are not identical - the polyline start point is different.
Move (Relocate Start Point, OR) the start point on the second "o" from one to two and see what happens.

Husky-2019.04.24-02.png
Husky-2019.04.24-02.png (18.05 KiB) Viewed 1118 times
Work smart, not hard: QCad Pro

Ico
Junior Member
Posts: 11
Joined: Wed Apr 24, 2019 2:39 pm
Location: Canada

Re: Added toolpath is on the wrong side

Post by Ico » Thu Apr 25, 2019 5:42 am

Thanks, Husky, for the quick response.
I am using QCAD/CAM 3.22 on Win 10, Intel Core i9-9900K.
First, I like to say that I am very impressed with QCAD. I had to change my way of thinking at the beginning – after all I was an AutoCAD user for many years before. Now, it’s a pleasure to use QCAD, and best part is that I constantly discover new (and better) ways to do things.
Props to the developers!
Now, back on topic! Lol
I have tried that and many other things, and found that nothing else helps, except changing the proximity of the contours (relative to each other) or separating the contours into different toolpaths. For example, in this particular drawing, if you create two toolpaths, one containing all the letters except the “bad” “o” and a second toolpath with just the “bad” “o”, all of the letters will be cut correctly.
I changed the drawing from my previous post to illustrate that:
1. I deleted the “bad” “o”.
2. I copied the “good” “o” to the same location where the bad one was.
3. I copied the good “o” one more time, but at a higher location on the drawing.
4. I selected all contours and did “CAM>Update toolpath from selection” to add the two new copies of the good “o” to the existing toolpath.
The result is: The first copy of the good “o” (located at the bad “o” location) became bad, where the second copy is good.
This also happens the other way, meaning when I have several contours that need to be cut on outside, some of them get a toolpath on the inside.
Moving the contours relative to each other solves the problem, but unfortunately that is not an option for me. So, I had to formulate a workaround by other means. The only other solution that I have found is to separate the problematic contours into different toolpaths.
I will explain what I do in more detail, hoping to illustrate all of this better.
I have many drawings of different parts (I call them “Parts”), which contain contours that need to be cut outside (I call them “Outlines”) and also contours to be cut on the inside (“Islands”). The sample drawing attached to this post is a “Parts” drawing. You can imagine those as panels with bunch of various shaped holes in them.
To start the process, I open my own template drawing (“Sheet”) which represents a 4’x8’ sheet of metal. Then I import all the needed “Parts” into the “Sheet”, and I nest them to minimize wasted material. Note that those “Parts” are different for almost every new “Sheet” I nest. Then I select all the “Islands” on the whole sheet (this selection will contain contours that came from all of the imported “Parts”). Then I add a new toolpath with that selection and I set it to be cut on inside. I do the same with the “Outlines”, except their own toolpath is set to cut on outside.
After each “Add Profile toolpath”, QCAD creates the toolpath needed (2 profile toolpaths total). While most of the “Islands” are correct (cut on inside), some will show as cut on outside (wrong). And same thing happens in the second toolpath for the “Outlines” – most are cut on the outside, but some will be on the inside (also wrong).
So, my workaround right now is to actually create toolpaths in each and every “Parts” (which I don’t really need, since toolpaths are lost at import) and separate the “Islands” within that drawing into 1,2,3 or 4 separate toolpaths that are in fact correct. Then, in order to be able to retain that information during the import into the “Sheet”, I separate the contours from each toolpath into 4 corresponding layers named “Islands Pass1” “Island Pass2” “Islands Pass3” and “Islands Pass4”. Then, when I import the “Parts” into the “Sheet” each of those layers contains contours that do not interfere with each other and can be on the same toolpath. I hope it makes sense to you, even I had to read it twice after I wrote it! LOL
Hopefully you guys can recreate this on your own computers.
Since the workaround that I am using is rather tedious and time consuming, I was hoping this could be easily fixed.
Thanks in advance!
Attachments
Robinsons (forum2).dxf
(1.63 MiB) Downloaded 34 times

Ico
Junior Member
Posts: 11
Joined: Wed Apr 24, 2019 2:39 pm
Location: Canada

Re: Added toolpath is on the wrong side

Post by Ico » Thu Apr 25, 2019 2:39 pm

I was also looking at the QCAD output on the command line, and it shows that for the problem contour.
Attachments
Contour is a hole.png
Contour is a hole.png (14.03 KiB) Viewed 1090 times

User avatar
Husky
Moderator/Drawing Help/Testing
Posts: 2486
Joined: Wed May 11, 2011 9:25 am
Location: USA

Re: Added toolpath is on the wrong side

Post by Husky » Thu Apr 25, 2019 9:08 pm

So, I was able to play a bit and my short conclusion is: The tool is confused by neighboring entities/shapes.

Why?
If I select all letters and create the tool path the first / left "o" is created wrongly:

Husky-2019.04.25-01.png
Husky-2019.04.25-01.png (165.12 KiB) Viewed 1074 times

if I select all letters except the "R" the tool path is created correctly:


Husky-2019.04.25-02.png
Husky-2019.04.25-02.png (149.41 KiB) Viewed 1074 times
What means something is messing with the calculation for the tool path based on the existing neighbor entities/shapes.

I would consider that as a bug!
Work smart, not hard: QCad Pro

Ico
Junior Member
Posts: 11
Joined: Wed Apr 24, 2019 2:39 pm
Location: Canada

Re: Added toolpath is on the wrong side

Post by Ico » Thu Apr 25, 2019 9:42 pm

Thanks again Husky!
I did play with it too, and i found that if i move the problem "o" just 1/16" up, it will be cut correctly. So i figure is some kind of interference with the other letters/objects/contours.

I don't know how to submit a bug report.
Using QCAD/CAM 3.22 on Win10 64-bit.

User avatar
andrew
Site Admin
Posts: 6154
Joined: Fri Mar 30, 2007 6:07 am

Re: Added toolpath is on the wrong side

Post by andrew » Thu Apr 25, 2019 9:58 pm

You might want to try this with the latest snapshot release 3.22.0.9 as the problem might have been fixed meanwhile.

Snapshot releases are available from your download link under "Snapshots".

Ico
Junior Member
Posts: 11
Joined: Wed Apr 24, 2019 2:39 pm
Location: Canada

Re: Added toolpath is on the wrong side

Post by Ico » Thu Apr 25, 2019 10:08 pm

Thanks Andrew,

I would try it, and report back.

User avatar
Husky
Moderator/Drawing Help/Testing
Posts: 2486
Joined: Wed May 11, 2011 9:25 am
Location: USA

Re: Added toolpath is on the wrong side

Post by Husky » Thu Apr 25, 2019 10:22 pm

andrew wrote:
Thu Apr 25, 2019 9:58 pm
You might want to try this with the latest snapshot release 3.22.0.9 as the problem might have been fixed meanwhile.
Works! :D :wink:
Work smart, not hard: QCad Pro

Ico
Junior Member
Posts: 11
Joined: Wed Apr 24, 2019 2:39 pm
Location: Canada

Re: Added toolpath is on the wrong side

Post by Ico » Thu Apr 25, 2019 11:25 pm

Yes, it does work correct in the snapshot. I will try my other drawings to confirm it works everywhere.
Thanks guys! It will save me a lot of work. Amazing stuff!!!
Using QCAD/CAM 3.22 on Win10 64-bit.

Ico
Junior Member
Posts: 11
Joined: Wed Apr 24, 2019 2:39 pm
Location: Canada

Re: Added toolpath is on the wrong side

Post by Ico » Fri May 03, 2019 7:23 pm

I have checked all my drawings by re-doing the toolpaths on them, and I am happy to report that QCAD did everyone of them correctly (in Snapshot 3.22.09). Also I have noticed that if I select the "Outline" and the "Islands/Holes" together and make a new toolpath with setting for outside, QCAD will do the "Islands/Holes" first on the inside (correct) and then the "Outline" on the outside (also correct). This is even better than my expectations! Amazing!

The only other 2 things I wish for are:
- Some sort of manual nesting, i.e. inserted blocks/parts bump into each other at pre-set distance and are not allowed to overlap.
- Auto change of starting points (i.e. to a mid-point of entity) for polylines/contours which don't have a meaningful (for CAM toolpaths) start point.

QCAD/CAM is already the best all-in-one solution, I tried few others before! But adding the manual nesting will make it, well, kick-ass!

Husky and Andrew, thanks again for the help with this!
Using QCAD/CAM 3.22 on Win10 64-bit.

User avatar
Husky
Moderator/Drawing Help/Testing
Posts: 2486
Joined: Wed May 11, 2011 9:25 am
Location: USA

Re: Added toolpath is on the wrong side

Post by Husky » Fri May 03, 2019 8:10 pm

Thank you for the feedback!
Ico wrote:
Fri May 03, 2019 7:23 pm
The only other 2 things I wish for are:
- Some sort of manual nesting, i.e. inserted blocks/parts bump into each other at pre-set distance and are not allowed to overlap.
Yep, that would be nice but in the meantime you can use open source nesting programs. Just google .... :wink:

At the moment I'm testing deepnest (https://deepnest.io) for me. Till now I like it ..... :shock:
Work smart, not hard: QCad Pro

Post Reply

Return to “QCAD/CAM”