Butterfly example with beziers and 2D/3D Export, OpenJSCAD

butterfly.jscad

// title      : OpenJSCAD Bezier, 2D/3D Export Example
// author     : Natalie Freed
// sources    : 2D/3D export technique from Lamp Shade Example

function getParameterDefinitions() {
    return [{ name: 'height', type: 'float', initial: 6, caption: "height:" },
            {
                name: 'type',
                type: 'choice',
                values: ["2D", "3D"],
                captions: ["2D (DXF output)", "3D (STL output)"],
                caption: 'Export type:',                          
                initial: "2D"                            
            }];
}

function main(params) {
    //draw a butterfly wing with bezier curves
    var wing = new CSG.Path2D([ [0,0] ], false);
    wing = wing.appendBezier([ [-19, -158], [189, -38], [43, 20] ]);
    wing = wing.appendBezier([ [100, 48], [46, 133], [0, 34] ]);
    wing = wing.close();
    
    //make the curve into a surface
    wing = wing.innerToCAG();
    //make a second wing, mirrored in X
    var wing2 = wing.mirroredX();
    //connect the two wings
    var wings = union(wing, wing2);
    //mirror them in Y so they face forwards
    wings = wings.mirroredY();
    
    //if we're in 2D mode, return the 2D shape
    if(params.type === "2D") {
        return [wings];
    }
    //if we're in 2D mode, extrude the shape to make it 3D
    else {
        var wingsExtruded = wings.extrude({ offset: [0, 0, params.height]});
        return wingsExtruded;
    }
}

whats CSG?