Overview
of 3D graphics in Windows Presentation Foundation
Windows
Presentation Foundation 3-D classes allow developers to create 3D models
in Windows applications as a part of GUI.
Creating
3D Models involves
1. Creating 3D surfaces by defining more number of triangular surfaces
2. Assigning Material property for the 3D model
3. Creating light sources
4. Creating camera to visualize the 3D model from different angle.
5. Animating the models
Coordinate System
Cameras
and Projections
With Camera,
a 3D model can be viewed in different angles. The camera can be positioned
at any distance from the model for a particular view angle. The NearPlaneDistance
and FarPlaneDistance properties of ProjectionCamera limit the range for
the projection, the model within this range are displayed in the screen.
There
are two types of Camera available in WPF
· PerspectiveCamera
· OrthographicCamera
Using Perspective
camera, 3D models can be visualized more realistically. There is a vanishing
point for Perspective camera, the point where the edges of the surfaces
tend to join. In Orthographic projection, edges are parallel.
Model
and Mesh Primitives
At present
the Windows Presentation Foundation supports modeling geometries with
GeometryModel3D and the Geometry property of this particular model takes
a mesh primitive.
There
are two types of 3D models
Mesh
Solid
The Mesh
is a model defined using surfaces, formed using triangle. The solid model
is it defined using volume. The WPF supports 3D models based on the mesh
geomentry.
To create
a 3D Model
1. Define vertex points in 3D co-ordinate system ( P1 to P8 )
2. Define the indexes of 3 vertices, which form a triangular surface.
3. Define normal vector for each triangle
4. Define more no of triangular surfaces as above to form a 3D model.
Applying
Materials to the Model
We need to apply material to the mesh surface. Depending on the material
surface property, they get illuminated differently when the light rays
fall on the surface.
There are
three types of materials, based on their light reflecting property.
1. Diffuse
Material - don't reflect light, ex. cotton clothes.
2. Specular Meterial - reflect light so the surface looks glossy, ex.
floor tiles
3. Emissive Material - emits lights equal to the color of brush
Illuminating
the Scene
At least one light is included in the scene (3D models & space). This
makes the 3D model visible. They create different effect shadow, reflection
effect on the materials surfaces.
There
are 4 types of lights
Ambient light - Illuminates all surfaces equally, regardless of its orientation
and location.
Directional
light - It is like a beam of light rays. It has only the direction vector,
but no location.
Point light
- It has position information. The objects near to the light get more
illuminated than the objects in the far.
Spot light
- it is derived from the point light and directional light. They have
both direction and position. InnerConeAngle, OuterConeAngle, and position
are specified.
Transforming
Models
Transforming 3D models are possible. It is very difficult to define vertex
of the model for each location, rotation and scale. Instead the transformation
of these vertexes is possible in WPF.
Animating
Models
The animation is used to visualize the 3D models in motion. They are based
on time interval and location. The following object can be animated.
The object or group of objects, camera, light, or combination of these
can be animated.
The properties of these WPF elements are changed at different time interval
to create animation effect.
Thus as a
developer you can use the Windows Presentation Foundation 3-D classes
to create 3D model for giving more visual representation of their system.
