Hi All,
Trying to create a visual for a sheet of steel which is going to be laser cut. The artwork contains some problem points which I cant find. Rebuilding doesnt seem to remove the problem which I suspect is a flip curved amongst one of the closed curves.

Any ideas on how to solve problem and find them would be great.

Hi Alex, it's probably some areas of self intersection. Any flipped direction curves should be automatically reoriented but self intersections will cause that kind of thing.

The way I'd narrow it down is to use Construct > Planar starting with just the outline and one interior letter and then if that's ok use undo and add in another letter until it gets messy then you can inspect that particular letter more closely. A good way to inspect it is to turn on control points and then yank each one over and if it shows an expected connection that will be the problem area.

I found the first one on the "t" here:





- Michael

Hi Alex, I examined most of it and found 17 anomalous areas, they are marked with point objects in the attached file.

Some are little curly-cue self intersections like above and there are a couple spots with back-tracking.

Zoom in closely to each of those point object locations and that's where it needs cleanup.

- Michael

Hi Michael,

Many thanks for the sharp eye response - zooming into the nano world does indeed highlight the flipped curves.

Is it possible for a script to highlight a cluster of Points based on a set criteria. Like if a curve was selected and the script turned on any points that where within 2mm from each other. This is a common problem when sending files for laser cutting and could be a good tool to detect problems like this. Not sure what would be involved in something like this.

Your A grade service is always appreciated.

regards
Alex.

Hi Alex,

re:
> Is it possible for a script to highlight a cluster of Points based on a set criteria. Like if a curve was
> selected and the script turned on any points that where within 2mm from each other.

Please try the attached script.

- Michael

Seems not working...
All dialogs work but no result at the end...
Show Points must be enable ? (enabled)

What must be the result ? Enlighted points or merge them ?

Hi Pilou, the way it works is you select curves, then run the command and enter in a distance value. Any curve control points that are within that distance of their neighboring points will be marked with a point object.

If there are no such points then it is normal that you would not get any output.

For a demo, load the .3dm file attached to the first message of this thread, select the curves and run the command and put in a distance value of 1. There will be points marking areas that have curve control points that are 1mm or closer to their neighbors. Those are areas that would be good to investigate for problems.

- Michael

Perfect!
Will be added to my French repository script! ;)

Done but not yet translated! :)
http://moiscript.weebly.com/pts-dune-courbe.html

WOW - Michael that is a great tool - a common workflow is taking art out of Illustrator and getting it ready for Laser Cutting the DXF module in illustrator is about 25 years old and should be made illegal it does a terrible job in export for bigger industrial laser cutters which still only take DXF files for cutting.

I usually take the file into Rhino or MOI for export to DXF and the files always need a clean up prior to export this really helps in identifying point clusters and deleting any excess point out of the curves for problem free cutting.

Amazing backup service.

All the best
Alex.

Interesting thread and thanks for the script Michael!

I am wondering about the following, regarding those dense control points
in the letters. Because MoI does not use Bezier curves like Illustrator what
would happen for example if one loads those Bezier curves for example into
ViaCAD (which I no longer have) and then change in there the Curve type
to what MoI likes and then export and import into MoI.

Would that get rid of the many control points?

Regards
Stefan

Hi Stefan,

re:
> I am wondering about the following, regarding those dense control points
> in the letters. Because MoI does not use Bezier curves like Illustrator what
> would happen for example if one loads those Bezier curves for example into
> ViaCAD (which I no longer have) and then change in there the Curve type
> to what MoI likes and then export and import into MoI.

Beziers are a subset of NURBS, so MoI can import a Bezier curve drawing from 2D illustration programs exactly.

Going the reverse direction can be more problematic - it is possible to break a NURBS curve into a chain of Bezier curves with the exact same shape, but if the NURBS curve uses rational control points (which will be the case for conics like circles, ellipses, ...) then you get a chain of rational beziers while the illustration formats only support non-rational beziers. So in that case there has to be a rebuilt curve exported instead of the exact curve.

But on the other direction there isn't any refitting, if there are a lot of points then that's just what was in the file.


> Would that get rid of the many control points?

If it did it would involve changing the shape by some amount.

- Michael

I send files for Cutting to an industrial laser and they run JETCAM and PEP Technology on their machines. Prior to creating a cutting path NC file both programs will highlight problem areas they put a circle highlighting flipped or duplicate points on a curve. They are both high end applications each seat costing thousands of dollars a year - So this solution offers the same result in a very elegant manor. I havent seen any auto repair tools out there as the coding to work out the scenarios for the errors would be highly complex. But once again MOI offers a simple solution to a common problem. Instead chasing countless points highlighting dense areas is usually a good starting point to a problem leaving the user to decide the best manor for clean up.

Thanks again.