BREPs shadow like MeshShadow?

I do need to extract the contour of some objects projected into the XY plane and I do found a component that it is working called MeshShadow. Unfortunately, when I bake the result I do get only polylines composed from small segments instead of perfect circles and arcs. It is there a similar component that can generate perfect circles and arcs?

MShadow

Make 2D creates curves, so does projecting section curves. The sphere circumference is a perfect circle, but the result of the plane brep intersection isn’t. You could fit a circle to the section curve but in the end that’s not much different from fitting a circle or curve to the projection of the mesh shadow component.

projection.gh (114.6 KB)

Thank you. With what I do need to change the vector from the picture above to make this definition to work with other geometries?

P.S. BTW, the Make2D component I already tried without success, because it is messing the overall contours with the pockets that are touching the external contours.

Right click a component and select Set one Brep. Instead of an arbitrary vector in the XZ plane, you could replace the vector component with a Z-vector?

My example only really works with very simple geometries.

What are you actually trying to achieve?

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I do need to extract the interior/exterior overall contours of the pieces I do need to mechanize, and I can’t find any viable way to do this task. I already tried Make2D that it is messing all the contours with the pockets touching the contour, I tried with evaluating the normal of the surfaces which it is not filtering very well the vertical surfaces, giving-me mixed results, I tried to “Squash” all the surfaces into a plane and make a MergeAllCoplanarFaces or BooleanUnion operation witch also fails with a lot of pieces and I also recently discovered the MeshShadow method into a “BarkBeetle” cluster user object component (“Automill” => CutoutCurves = this is what I am searching to obtain) which works but it is giving-me only jagged polylines instead of perfect circles and arcs.

I don’t get it :slight_smile:

What are you doing with these parts?

I am cutting them using a CNC machine. I do take the parts and I do need to “dissect” the 3D objects into curves that I do need to sort them in different categories for mechanization (router cutting and drilling operations).

The overall contours I am further classifying if they are interior or exterior. The exterior ones I do make them CCW direction and put them in a layer called “XLYP1T$CutThrough_E7$”. The interior shapes I further separate into three main categories: Interior cutouts (CW cutout direction, they are going into the same “XLYP1T$CutThrough_E7$” layer), pockets and circles for drilling (“XLYP1T$Drill_Through_3$” or “XLYP1T$Drill_14_5$” where 14 it is the depth and 5 it is the drill diameter) and I do put all this shapes in different layers according with mechanization needs and the depths of cutting.

After that I do bake all this curves and export the result as a DXF file that I am importing in Maestro CAM software who can read the information from this layers and it is assigning automatically the corresponding mechanizations.

Ok, got it. I did a similar process to extract DXF files to import in woodwop. It’s complicated :slight_smile:

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I also used WoodWop before but now I am working with an SCM machine and the CAM software of the machine (SCM Maestro) can read only layered DXF files instead of 3D objects.

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Interesting stuff.

I am using the Sasquash component “SurfaceBorder” to separate the interior/exterior contours and the “FlipCurveClocwise” to orient the curves CW or CCW.

The only issue it is to find a viable method to extract the “master” surface contour of the pieces.

In my case, the master surface would be the largest face with the normal parallel to the Z-vector

The problem it is that there are also grooves and holes into the pieces. I thought to find the Z level of the pieces where they do have the most solid inside but this method also don’t works as the pieces can have mechanization on top and also on bottom face and this mechanizations can cross the solid. So the only viable option remains to find the “shadow” or to “squash” all the surfaces and find a way to extract the overall resulting contour.

What if you create a bounding box and filter the faces which have their centroid coincident with the upper surface of the bbox?

The pieces are quite different from one job to the next and some of them do have fillets, chamfers, mechanization on both sides.

Top_Bottom_Mechanisation.3dm (912.1 KB)

Finaly I get the contours after “squashing” the surfaces. Now I do face another challenge. To get rid of duplicated arcs and curves that I do have.