How to edit a CAD file?

Let's create a function to add, change, and remove entities. In this example we use the Entities.dxf file. You can find it in ...\CAD .NET 14\Files.

By default, the CAD .NET folder is unpacked to Documents.

The following picture illustrates the Entities.dxf file by default.

Entities.dxf by default

1. Add the using directive with the CADImport and CADImport.FaceModule namespaces.

using CADImport;
using CADImport.FaceModule;

More information about CADPictureBox

The CADPictureBox class is the basic implementation of the control element for displaying vector drawings. Visually CADPictureBox includes only area for drawing visualization and can be extended by the required control elements in the project under development.
To get more information about the CAD .NET controls, see What controls does CAD .NET have?

2. Use the control element of the CADPictureBox class:
   • Set the Location property as new Point(10, 30).
   • Set the BackColor property as Color.Black.
   • Set the Size property as new Size(995, 500).
   • Finally, add it to the form.

...

CADPictureBox pictureBox1 = new CADPictureBox(){
  Location = new Point(10, 30),
  BackColor = Color.Black,
  Size = new Size(995, 500),
}

public Form1()
  {
    Controls.Add(pictureBox1);
    InitializeComponent();
  }   

3. Add a new button. Name it EditDrawing. Then create the EditDrawing_Click function to load a CAD file by click. Also, add the OpenFileDialog component and name it openFileDialog1.

private void EditDrawing_Click(object sender, EventArgs e){

4. Create a new instance of the CADImage class. Also, change the BackgroundColor property of this CADImage instance.

  CADImage vDrawing = CADImage.CreateImageByExtension(@"Entities.dxf");
  vDrawing.LoadFromFile(@"Entities.dxf");
  vDrawing.BackgroundColor = Color.Azure;

Tip

We recommend creating a new drawing object using CreateImageByExtension in case of importing from an existing file or stream.

5. Create a new instance of the CADLine class:
   • Add this entity to the drawing with the AddEntity method.
   • Set the Point property as new DPoint(50,0,0).
   • Set the Point1 property as new DPoint(50, 70, 10).
   • Set the LineWeight property as 1.
   • Use the Loads method to fill the internal data of the entity to prepare it for drawing.

  CADLine vLine = new CADLine();
  vDrawing.CurrentLayout.AddEntity(vLine);
  vLine.Point = new DPoint(50, 0, 0);
  vLine.Point1 = new DPoint(50, 70, 10);
  vLine.LineWeight = 1;
  vDrawing.Converter.Loads(vLine); 

6. Edit the Color and LineWeight properties. Use the Loads method to fill the internal data of the entity to prepare it for drawing.

  vDrawing.CurrentLayout.Entities[1].Color = Color.Blue;
  vDrawing.CurrentLayout.Entities[1].LineWeight = 2;
  vDrawing.Converter.Loads(vDrawing.CurrentLayout.Entities[1]);

7. Remove the third entity using RemoveAt(). This method removes the element with the specified index from the Entities list.

vDrawing.CurrentLayout.Entities.RemoveAt(2);

8. Use the GetExtents method to recalculate drawing extents.

vDrawing.GetExtents();

9. Declare the local variable vRect and specify RectangleF as its type. This variable stores four floating values that represent the location and size of a CAD file. Use the following code to fit the CAD file to pictureBox1. Finally, render the result with the Draw method.

RectangleF vRect;
double vRatio = (double)(vDrawing.AbsHeight * pictureBox1.ClientSize.Width)/ (vDrawing.AbsWidth * pictureBox1.ClientSize.Height);
if (vRatio > 1)
  vRect = new RectangleF(0, 0, (float)(pictureBox1.ClientSize.Width / vRatio), (float)pictureBox1.ClientSize.Height);
else
  vRect = new RectangleF(0, 0, (float)pictureBox1.ClientSize.Width, (float)(pictureBox1.ClientSize.Height * vRatio));
vDrawing.Draw(pictureBox1.CreateGraphics(), vRect);

You have created the function to add, change, and remove entities.

The following picture illustrates the result.

Left: Entities.dxf by default. Right: Entities.dxf after the changes

The full code listing.

...
using CADImport;
using CADImport.FaceModule;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form

    {
        CADPictureBox pictureBox1 = new CADPictureBox()
        {
            Location = new Point(10, 30),
            TabIndex = 10,
            BackColor = Color.Black,
            Size = new Size(995, 500)
        };
        public Form1()
        {
            Controls.Add(pictureBox1);
            InitializeComponent();
        }     
        private void EditDrawing_Click(object sender, EventArgs e)
        {
          CADImage vDrawing = CADImage.CreateImageByExtension(@"Entities.dxf");
          vDrawing.LoadFromFile(@"Entities.dxf");
          // Changing background color
          vDrawing.BackgroundColor = Color.Azure;
          // Creating a new entity - line
          CADLine vLine = new CADLine();
          vDrawing.CurrentLayout.AddEntity(vLine);
          vLine.Point = new DPoint(50, 0, 0);
          vLine.Point1 = new DPoint(50, 70, 10);
          vLine.LineWeight = 1;
          vDrawing.Converter.Loads(vLine);        
          // Removes the circle entity from the Entities.dxf drawing
          vDrawing.CurrentLayout.Entities.RemoveAt(2);
          // Editing the entity
          vDrawing.CurrentLayout.Entities[1].Color = Color.Blue;
          vDrawing.CurrentLayout.Entities[1].LineWeight = 2;
          vDrawing.Converter.Loads(vDrawing.CurrentLayout.Entities[1]);
          // Recalculates the extents of the drawing
          vDrawing.GetExtents();
          // Adjusting visualization sizes to the control area
          RectangleF vRect;
          double vRatio = (double)(vDrawing.AbsHeight * pictureBox1.ClientSize.Width) / (vDrawing.AbsWidth * pictureBox1.ClientSize.Height);
          if (vRatio > 1)
            vRect = new RectangleF(0, 0, (float)(pictureBox1.ClientSize.Width / vRatio), (float)pictureBox1.ClientSize.Height);
          else
            vRect = new RectangleF(0, 0, (float)pictureBox1.ClientSize.Width, (float)(pictureBox1.ClientSize.Height * vRatio));
          vDrawing.Draw(pictureBox1.CreateGraphics(), vRect);
        }
    }
}