DG Kernel Documentation

Patch Tutorial demonstrates incorporation of DG Kernel control into a simple Windows Form application using Microsoft Visual Studio. Source code for Patch sample is available in Samples\NET\VB\Patch\ folder of the installation directory.

The Application

Patch application creates a new truncated cone and allows modification of its parameters.

Step 1. Creating the project

Open Visual Studio. Select File > New > Project in the menu. In Projects types window select "Visual Basic". Make sure that "Windows Forms Application" is selected in the right-hand pane. Enter "Patch" in the Name edit box. Select location for the project folder and click OK.

In Solution Explorer select the Form1.vb created by default and rename it (using context menu on right-mouse click) to Patch.vb. Accept the suggestion to rename related elements when asked.

Step 2. Inserting the DG Kernel control

In the menu select Project > "Add Reference...".

In the dialog open COM tab and select "KernelCAD .NET Pro ActiveX Control". Press OK. If the control was already used in Visual Studio this step is not required and the OK button will be disabled.

Open Patch form in design mode and adjust size of the form to 890, 532 by pasting or typing the pair in Size property of the Properties Window (View > "Properties Window"). Change also Text property to "Patch".

In Toolbox panel (View > Toolbox) open Components tab, select "KernCADnet Control", press Esc key to hide the toolbox and place the control on the left in the form. Save All. A new member of type AxKernCADnet.AxKernCADnet called AxKernCADnet1 will be added to the Patch class.

Open Build > Configuration manager in Visual Studio menu. In the Active Solution Platform select New. Select either x64 or x86 depending on bitness of the installed DG Kernel. This is a required step, as DG Kernel is a native control. It has to be done in this sequence, after insertion of the control.

Open Class View, double click the AxKernCADnet1 field of the Patch class and in the opened Patch.designer.vb rename all occurrences of AxKernCADnet1 to m_kernCAD.

Select the control in design view and change its size to 698, 482 using Properties Window. On rare occasions control may throw an exception at this point. Please save all then, close the solution and restart Visual Studio. Generally, it is recommended to close the form designer as soon as possible.

Right-click on the control and select Properties. The form shows properties of the control. The properties can also be accessed via the Properties Window of Visual Studio. The main one, ModelPath, can point to an .mdg model file or a file in any other supported format. We will leave it empty as our entity will be created in the code.

Open the Object Browser (View > Object Browser menu option). Expand Interop.KernCADnet and its child node. This node displays all necessary information about types, interfaces and their methods available in the component.

Step 3. Creating the Entity

To create handler for the Load event of the form, in design mode, click on the form outside the control. Click Events icon on the top of Properties Window. Select Load row in the list and double-click the row on the right. A new Patch_Load() method will be added to the Patch class.

Add line:
Imports KernCADnet
at the top of the Patch.vb

Next we will get access to IModel_DG interface implemented by the control. Add to Patch_Load() the next line (without the (A) annotation):
Dim iModel As IModel_DG = m_kernCAD.GetModel() (A)

Add the following declarations to the Patch class:
Dim m_iEntity As IEntity_DG
Dim m_baseRadius As Double
Dim m_topRadius As Double
Dim m_height As Double

Initialise the parameters in New() Patch constructor or on start of Patch_Load() as:
m_baseRadius = 10
m_topRadius = 5
m_height = 10

Add the following three lines just below the line (A):
Dim iStdShape As IStdShape_DG = iModel
m_iEntity = iStdShape.Cylinder(m_baseRadius, m_topRadius, m_height)
iModel.AddEntity(m_iEntity)
The first line obtains an interface for creation of basic shapes. The second line creates a cylindrical object and stores its reference in m_iEntity. The third line adds the entity to the model to be displayed in the 3D view.

Add the following two lines at the end of Patch_Load():
Dim iView As IView_DG = m_kernCAD.GetView()
iView.Reset(True, True)

The first line accesses IView_DG, which is the root of the view-related functionality and the second line refits the view to include the new object.

Step 4. Implementing Modifications of the Object.

Add three edit boxes for the parameters and an Apply button to the form. Please make sure the text in edit boxes coincides with the initial values. The controls can be copied in design mode from the installed completed version of the sample

In handler of the Apply button, add:
m_baseRadius = Double.Parse(editBaseRad.Text)
m_topRadius = Double.Parse(editTopRad.Text)
m_height = Double.Parse(editHeight.Text)

Dim iModel As IModel_DG = m_kernCAD.GetModel()
Dim iStdShapeRef As IStdShapeRef_DG = iModel
iStdShapeRef.Cylinder(m_baseRadius, m_topRadius, m_height, m_iEntity)

m_kernCAD.UpdateView()

Notice the different version of interface used. IStdShapeRef_DG is designed for modification (and creation) rather than creation only. The last line redraws the window.

Run the application and test modifications of the entity.