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Cross View Visual Basic 6 Sample

Overview

Details Of Application Design

The Samples\VB\CrossView folder of the installation directory contains three separate project folders for High, Mid and Low level implementations

Normals calculation is implemented only in the Low level.

The CrossViewForm  uses calls to Activate(), UpdateCrossSectionView() and Setup() methods to delegate the relevant task to the specific implementation class.

Low implementation of the sample provides also a way to display and test mapping of 2D coordinates of Crsosssection view (right hand window) and coordinates the correspondent point in 3D space. Low level transforms coordinates of the crossection line to 2D coordinates in the local frane which defines the plane.

Implementation

The most critical work is done inside UpdateCrossSectionView() of the form which is called on "Update Cross-Section View" button clicks and also on start of the application or when implementation type is changed. The method delegates the call to UpdateCrossSectionView() of the currently active implementation class via virtual call.

In case of Low level implementation LowImplementation.AlignViewPlane() method uses IFrame.SetAxes to align z and x axes of the Eye Frame for two dimensional style of view

Cross section plane is rendered using the first clipping plane of the pipe section. The clipping plane is not enabled because it used only for rendering purpose. Preparation of the plane is done in SetupRenderingPlane() method of the form/dialog

Notice also the way frame of the 2D View is rendered inside of OnClientDraw(). It uses IGraphicItem queried from IView in CreateFrameGraphicItem().