Programming WPF, 2nd Edition

Transforms

Just as you can apply a transform to any 2D element in WPF, you can also transform any ModelVisual3D, or any of the types derived from Model3D. The set of transforms is much the same—you can rotate, scale, shear, or translate any part of the 3D model. However, to effect these operations in three dimensions requires slightly more information than it does in two dimensions, so we cannot simply use the 2D transform classes in 3D. WPF therefore defines a set of 3D transform types, all of which derive from the abstract Transform3D class.

TranslateTransform3D

TranslateTransform3D changes the position of an object. It has three properties: OffsetX, OffsetY, and OffsetZ, indicating the distance to move in each direction.

Translation can provide a convenient means of reusing the same 3D shape many times over. Example 17-20 shows an example of this—it defines the scene that was shown in Figure 17-1, consisting of five identical cylinders in a row.

Example 17-20. Positioning models with TranslateTransform3D

<ModelVisual3D Content="{StaticResource cylinderModel}">
  <ModelVisual3D.Transform>
    <TranslateTransform3D OffsetX="−1" OffsetZ="0" />
  </ModelVisual3D.Transform>
</ModelVisual3D>
<ModelVisual3D Content="{StaticResource cylinderModel}">
  <ModelVisual3D.Transform>
    <TranslateTransform3D OffsetX="−0.5" OffsetZ="−0.5" />
  </ModelVisual3D.Transform>
</ModelVisual3D>
<ModelVisual3D Content="{StaticResource cylinderModel}">
  <ModelVisual3D.Transform>
    <TranslateTransform3D OffsetX="0" OffsetZ="−1" ...