Creating a polyline using distances between points.

[baw6718]

Hello I am new to the .Net api. I am aware of creating a polyline and using .AddVertexAt() to give the points, my question is if I want to create a polyline in acad I generally will pick a point and then type out @10.5<0 or something similar of that nature to pick my next point. Is it possible to add vertices to a polyline in .Net giving it the distance and angle of one point2d to the next point2d?

Example:

acPoly.AddVertexAt(0, New Point2d(0,0),0,0,0)

acPoly.AddvertexAt(0, New Point2d(1,0),0,0,0)

but instead?

acPoly.AddVertexAt(0, New Point2d(0,0),0,0,0)

acPoly.AddVertex ( use code equivalent of  New Point2d = @10.5<0 from point at 0 index)

[DiningPhilosopher · Accepted solution]

Here's a few C# extension methods for Point3d that compute polar and spherical points relative to a given Point3d.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Autodesk.AutoCAD.Geometry
{
   public static class AcGeExtensions
   {
      /// 2D Polar specificiation (distance/angle)

      public static Point3d GetPointAt( this Point3d basepoint, double distance, double AngleInXYPlane )
      {
         return new Point3d(
            basepoint.X + ( distance * Math.Cos( AngleInXYPlane ) ),
            basepoint.Y + ( distance * Math.Sin( AngleInXYPlane ) ),
            basepoint.Z );
      }

      /// Spherical Coordinate (radius/phi/theta)
   
      public static Point3d GetPointAt( this Point3d center, double radius, double phi, double theta )
      {
         double phicos = Math.Cos( phi );
         return new Point3d(
            center.X + ( radius * phicos * Math.Cos( theta ) ),
            center.Y + ( radius * phicos * Math.Sin( theta ) ),
            center.Z + ( radius * Math.Sin( phi ) ) );
      }
   }
}

[norman.yuan]

It will depend on how you collect user input.

If you write code to get user input as a text string like "@10<0", then you have to first validate the text string to make sure it is in expected format and then you need to parse it into a number as distance and a number as angle. Then you can calculate the point, based on previous point, as shown in the other reply.

However, AutoCAD .NET API provides a built-in way to get point, which allows user to pick point, or enter point iin the standard AutoCAD input format (i.e. like "@10<0"). You do not need to do anything, the method returns the point. What the the magic method? it is:

Editor.GetPoint(PromptPointOptions options)

When you call this method with UseBasePoint option being true and BasePoint being specified, user can either pick a point or enter "@10<0" at command line. The method will give you a point back, spare you from doing geometric calculation.