Create Ellipse Example (C#)

//---------------------------------------------------------------------------
// Preconditions: Open a part document that contains
// an active sketch that has two sketch points.
//
// Postconditions:
// 1. Creates an ellipse circumscribing the two sketch points.
// 2. Inspect Immediate window for ellipse point data, theta, and equation.
//---------------------------------------------------------------------------
using Microsoft.VisualBasic;
using System;
using System.Windows.Forms;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
using SolidWorks.Interop.sldworks;
using SolidWorks.Interop.swconst;
using System.Runtime.InteropServices;
namespace CreateEllipse_CSharp.csproj
{
    partial class SolidWorksMacro
    {

        public void Main()
        {
            ModelDoc2 swModel = default(ModelDoc2);
            MathUtility swMath = default(MathUtility);

            swModel = (ModelDoc2)swApp.ActiveDoc;
            swMath = (MathUtility)swApp.GetMathUtility();

            // Check whether document is active
            if (swModel == null)
            {
                swApp.SendMsgToUser2("A part document must be active.", (int)swMessageBoxIcon_e.swMbWarning, (int)swMessageBoxBtn_e.swMbOk);
                return;
            }

            // Check whether document is a part
            int modelType = 0;
            modelType = swModel.GetType();

            if (modelType != (int)swDocumentTypes_e.swDocPART)
            {
                swApp.SendMsgToUser2("A part document must be active.", (int)swMessageBoxIcon_e.swMbWarning, (int)swMessageBoxBtn_e.swMbOk);
                return;
            }

            // Select a plane on which to sketch
            if (SelectPlane(swModel) == false)
            {
                MessageBox.Show("Could not select plane.");
                return;
            }

            SketchManager swSkMgr = default(SketchManager);
            swSkMgr = swModel.SketchManager;

            Sketch swSketch = default(Sketch);
            swSketch = swSkMgr.ActiveSketch;

            // Check whether a sketch is active
            if (swSketch == null)
            {
                MessageBox.Show("Please sketch a point for the center point, sketch another point to define the major axis, and run the macro again.");
                return;
            }

            const double pi = 3.1415926;

            // Get data from the points
            SketchPoint CtrPt = null;
            SketchPoint MajPt = null;

            swSkMgr = swModel.SketchManager;
            swSketch = swSkMgr.ActiveSketch;

            object[] vPoint = null;

            int i = 0;

            // Make sure the sketch is active
            if (swSketch == null)
            {
                MessageBox.Show("Please place the sketch in edit mode and run the macro again.");
                return;
            }

            // Make sure that at least two sketch points exist to define the position of the ellipse and its major axis
            vPoint = (Object[])swSketch.GetSketchPoints2();
            if (vPoint.GetUpperBound(0) == 0)
            {
                MessageBox.Show("Please sketch a point for the center point, sketch another point to define the major axis, and run the macro again.");
                return;
            }

            for (i = 0; i <= vPoint.GetUpperBound(0); i++)
            {
                if (i == 0)
                {
                    CtrPt = (SketchPoint)vPoint[i];
                }

                if (i == 1)
                {
                    MajPt = (SketchPoint)vPoint[i];
                }
            }

            MathVector MajVec = default(MathVector);
            double[] dirArr = new double[3];

            dirArr[0] = MajPt.X - CtrPt.X;
            dirArr[1] = MajPt.Y - CtrPt.Y;
            dirArr[2] = 0;

            MajVec = (MathVector)swMath.CreateVector((dirArr));
            MathVector MajVecunit = default(MathVector);

            MajVecunit = (MathVector)MajVec.Normalise();
            MathVector normVec = default(MathVector);

            dirArr[0] = 0;
            dirArr[1] = 0;
            dirArr[2] = 1;

            normVec = (MathVector)swMath.CreateVector((dirArr));

            MathVector MinVecunit = default(MathVector);
            MathVector MinVec = default(MathVector);
            double u = 0.0;

            MinVecunit = (MathVector)normVec.Cross(MajVecunit);

            double minlength = 50.0;
            u = minlength / 1000.0;

            MinVec = (MathVector)MinVecunit.Scale(u);

            // Ensure that the minor axis is less than the major axis so that
            // the equation returned is correct
            if (MajVec.GetLength() < MinVec.GetLength())
            {
                MessageBox.Show("The length of the minor axis must be less than that of the major axis.");
                return;
            }

            double[] pointvar;
            Object pointobj;
            pointobj = MinVec.ArrayData;
            pointvar = (Double[])pointobj;

            if (!(CtrPt.Z == 0) | !(MajPt.Z == 0) | !(pointvar[2] == 0))
            {
                MessageBox.Show("Only 2D sketch is allowed.");
                return;
            }

            // Sketch the ellipse
            SketchEllipse SkEllipse = default(SketchEllipse);
            SkEllipse = (SketchEllipse)swModel.SketchManager.CreateEllipse(CtrPt.X, CtrPt.Y, 0, MajPt.X, MajPt.Y, 0, CtrPt.X + pointvar[0], CtrPt.Y + pointvar[1], 0);

            swModel.ViewZoomtofit2();

            // Check that the sketch is an ellipse
            Object vEllipse = null;
            vEllipse = swSketch.GetEllipses3();

            if (swSketch.GetEllipseCount() == 0)
            {
                MessageBox.Show("An ellipse was not created. Please make sure that the sketch contains two points.");
                return;
            }

            // Extract information about the ellipse
            SketchPoint swStartPt = default(SketchPoint);
            SketchPoint swEndPt = default(SketchPoint);
            SketchPoint swCtrPt = default(SketchPoint);
            SketchPoint swMajPt = default(SketchPoint);
            SketchPoint swMinPt = default(SketchPoint);

            swStartPt = (SketchPoint)SkEllipse.GetStartPoint2();
            swEndPt = (SketchPoint)SkEllipse.GetEndPoint2();
            swCtrPt = (SketchPoint)SkEllipse.GetCenterPoint2();
            swMajPt = (SketchPoint)SkEllipse.GetMajorPoint2();
            swMinPt = (SketchPoint)SkEllipse.GetMinorPoint2();

            Debug.Print("Sketch points");
            Debug.Print("      Start Point   = (" + swStartPt.X * 1000.0 + ", " + swStartPt.Y * 1000.0 + ", " + swStartPt.Z * 1000.0 + ") mm");
            Debug.Print("      End Point     = (" + swEndPt.X * 1000.0 + ", " + swEndPt.Y * 1000.0 + ", " + swEndPt.Z * 1000.0 + ") mm");
            Debug.Print("      Center Point  = (" + swCtrPt.X * 1000.0 + ", " + swCtrPt.Y * 1000.0 + ", " + swCtrPt.Z * 1000.0 + ") mm");
            Debug.Print("      Major Point   = (" + swMajPt.X * 1000.0 + ", " + swMajPt.Y * 1000.0 + ", " + swMajPt.Z * 1000.0 + ") mm");
            Debug.Print("      Minor Point   = (" + swMinPt.X * 1000.0 + ", " + swMinPt.Y * 1000.0 + ", " + swMinPt.Z * 1000.0 + ") mm");

            // Algebraic equation for the ellipse
            double h = 0;
            double k = 0;
            double a = 0;
            double b = 0;
            double theta = 0;

            h = swCtrPt.X;
            k = swCtrPt.Y;
            a = 1 / (Math.Pow((swMajPt.X - swCtrPt.X), 2) + Math.Pow((swMajPt.Y - swCtrPt.Y), 2));
            b = 1 / (Math.Pow((swMinPt.X - swCtrPt.X), 2) + Math.Pow((swMinPt.Y - swCtrPt.Y), 2));

            // Return the tipping angle, theta; avoid divide by zero
            if (swMajPt.X != swCtrPt.X)
            {
                theta = Math.Atan((swMajPt.Y - swCtrPt.Y) / (swMajPt.X - swCtrPt.X));
            }
            else
            {
                theta = pi / 2;
            }

            Debug.Print("Theta of ellipse: " + theta);

            double c1 = 0;
            double c2 = 0;
            double c3 = 0;
            double c4 = 0;
            double c5 = 0;
            double c6 = 0;

            c1 = Math.Round((a * Math.Pow((Math.Cos(theta)), 2)) + (b * Math.Pow((Math.Sin(theta)), 2)), 2);
            c2 = Math.Round((a - b) * Math.Sin(2 * theta), 2);
            c3 = Math.Round((b * Math.Pow((Math.Cos(theta)), 2)) + (a * Math.Pow((Math.Sin(theta)), 2)), 2);
            c4 = Math.Round((-2 * a * h * Math.Cos(theta)) + (2 * b * k * Math.Sin(theta)), 2);
            c5 = Math.Round((-2 * a * h * Math.Sin(theta)) - (2 * b * k * Math.Cos(theta)), 2);
            c6 = Math.Round(1 - (b * (Math.Pow(k, 2))) - (a * (Math.Pow(h, 2))), 2);

            Debug.Print("Equation of the ellipse: " + c1 + "x^2 + " + c2 + "xy + " + c3 + "y^2 + " + c4 + "x + " + c5 + "y = " + c6);

            // NOTE: The coefficients of x and y in this
            //       equation represent a translation in the x-y plane.
            //       If they are 0, then the ellipse was not translated.
            //       Similarly the coefficient of xy represents
            //       a rotation. If it is 0, then the ellipse
            //       was not rotated.
            //
            //       The units on each axis are in meters.

        }

        public bool SelectPlane(ModelDoc2 Plane)
        {
            bool functionReturnValue = false;

            Feature featureTemp = default(Feature);
            featureTemp = (Feature)Plane.FirstFeature();

            while ((featureTemp != null))
            {
                string sFeatureName = null;
                sFeatureName = featureTemp.GetTypeName2();
                if (sFeatureName == "RefPlane")
                {
                    featureTemp.Select2(true, 0);
                    functionReturnValue = true;
                    return functionReturnValue;
                }

                featureTemp = (Feature)featureTemp.GetNextFeature();
            }
            return functionReturnValue;

        }



        public SldWorks swApp;

    }


}