Deduce a existant diameter or project a face

clément_schreiber · May 2016

Hello,
I would like to make a new Feature with FeatureScript. I would like to automatize the creation of screw thread. To do this I need to create a sketch on a surface. On this sketch I have to project the circle, or at least know the diameter of the screw.
For the moment, I could create a sketch plane with a circle but I could not deduce the diameter of the screw.
I absolutely need this function. If there is an other existent Feature to automatize the creation of a screw thread or a cosmetic screw thread it will be excellent.
I hope I was clear in the description of my problem.

kevin_o_toole_1 · May 2016

If you're starting with a cylinder, you can call evSurfaceGeometry() to get a Cylinder object, which has the radius stored as a ValueWithUnits.

To start off, below is a feature which evaluates a cylinder and places a plane on one side or the other, ready to be sketched on.

Source document (public): https://cad.onshape.com/documents/be8a5af4574bfcf507c34e38/w/e2dceba2d05f717895e64a88/e/1ddfec332143db1e7bfb2888

Feature code:

annotation { "Feature Type Name" : "Screw start" }
export const screwStart = defineFeature(function(context is Context, id is Id, definition is map)
    precondition
    {
        annotation { "Name" : "Shaft", "Filter" : GeometryType.CYLINDER, "MaxNumberOfPicks" : 1 }
        definition.shaft is Query;
        annotation { "Name" : "Flip side" }
        definition.flipSide is boolean;
    }
    {
        const cyl is Cylinder = evSurfaceDefinition(context, {
                "face" : definition.shaft
        });
        
        println("radius: " ~ toString(cyl.radius));
        
        const boundingBox is Box3d = evBox3d(context, {
                "topology" : definition.shaft,
                "cSys" : cyl.coordSystem
        });
        
        var sketchPlane;
        if (definition.flipSide)
        {
            sketchPlane = plane(
                cyl.coordSystem.origin + cyl.coordSystem.zAxis * boundingBox.maxCorner[2], // origin
                -cyl.coordSystem.zAxis, // normal
                -cyl.coordSystem.xAxis  // x 
            );
        }
        else
        {
            sketchPlane = plane(
                cyl.coordSystem.origin + cyl.coordSystem.zAxis * boundingBox.minCorner[2], // origin
                cyl.coordSystem.zAxis, // normal
                cyl.coordSystem.xAxis  // x 
            );
        }
        
        debug(context, sketchPlane);
        var sketch1 = newSketchOnPlane(context, id + "sketch1", {
                "sketchPlane" : sketchPlane
        });
        // Create sketch entities here
        skSolve(sketch1);        
    });

afbenevides · May 2016

Hi,

The info you need is in this thread https://forum.onshape.com/discussion/comment/4867/#Comment_4867 (comments from @Coleman and @LouGallo )

Just need to automate these steps with the feature script code.

Hope it is usefull

kevin_o_toole_1 · May 2016

If you're starting with a cylinder, you can call evSurfaceGeometry() to get a Cylinder object, which has the radius stored as a ValueWithUnits.

To start off, below is a feature which evaluates a cylinder and places a plane on one side or the other, ready to be sketched on.

Source document (public): https://cad.onshape.com/documents/be8a5af4574bfcf507c34e38/w/e2dceba2d05f717895e64a88/e/1ddfec332143db1e7bfb2888

Feature code:

annotation { "Feature Type Name" : "Screw start" }
export const screwStart = defineFeature(function(context is Context, id is Id, definition is map)
    precondition
    {
        annotation { "Name" : "Shaft", "Filter" : GeometryType.CYLINDER, "MaxNumberOfPicks" : 1 }
        definition.shaft is Query;
        annotation { "Name" : "Flip side" }
        definition.flipSide is boolean;
    }
    {
        const cyl is Cylinder = evSurfaceDefinition(context, {
                "face" : definition.shaft
        });
        
        println("radius: " ~ toString(cyl.radius));
        
        const boundingBox is Box3d = evBox3d(context, {
                "topology" : definition.shaft,
                "cSys" : cyl.coordSystem
        });
        
        var sketchPlane;
        if (definition.flipSide)
        {
            sketchPlane = plane(
                cyl.coordSystem.origin + cyl.coordSystem.zAxis * boundingBox.maxCorner[2], // origin
                -cyl.coordSystem.zAxis, // normal
                -cyl.coordSystem.xAxis  // x 
            );
        }
        else
        {
            sketchPlane = plane(
                cyl.coordSystem.origin + cyl.coordSystem.zAxis * boundingBox.minCorner[2], // origin
                cyl.coordSystem.zAxis, // normal
                cyl.coordSystem.xAxis  // x 
            );
        }
        
        debug(context, sketchPlane);
        var sketch1 = newSketchOnPlane(context, id + "sketch1", {
                "sketchPlane" : sketchPlane
        });
        // Create sketch entities here
        skSolve(sketch1);        
    });

clément_schreiber · June 2016

@afbenevides: Thank you for your answer, but I know how to do it graphically, but I am to lazy to do it each time I need it. It's why I would code a function with features
@kevin_o_toole_1: That is great! Thank you very much.

Deduce a existant diameter or project a face

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