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SoCameraInteractorDolly Method

Dolly - Makes the scene appear larger or smaller.

Namespace: OIV.Inventor.ViewerComponents
Assembly: OIV.Inventor (in OIV.Inventor.dll) Version: 2023.1.3.0 (2023.1.3)
Syntax
public void Dolly(
	float scaleFactor
)

Parameters

scaleFactor
Type: SystemSingle
Remarks

For a perspective camera, moves the camera forward or backward along the view vector (details below). For an orthographic camera, changes the height field to give a similar visual effect (moving an orthographic camera forward and backward has no visual effect). This is the preferred way to implement the visual effect of "zooming" in and out for a perspective camera. For a perspective camera, dolly means the same thing it means for a camera on a movie set.

Note: 'scaleFactor' is the inverse of what you might expect. To make the scene appear 2X larger, specify a scaleFactor of 0.5. This is because scaleFactor multiplies the camera 'focalDistance' or 'height'.

  • Perspective camera: The camera has a "focal point" located focalDistance units from the camera position along the view direction vector ( orientation). Unlike a real camera, neither focal point nor focal distance has effect on the appearance of the image. The focal point is just a reference point for some algorithms. You can think of it as the "look at" point. The OIV.Inventor.ViewerComponents.SoCameraInteractor.Dolly(System.Single) method computes a scale factor from the 'delta' parameter. A new "focal distance" is computed as the current value of the camera's focalDistance field multiplied by this scale factor. Then the camera's position field is modified so the camera is the new focal distance away from the focal point.

  • Orthographic camera: The OIV.Inventor.ViewerComponents.SoCameraInteractor.Dolly(System.Single) method computes a scale factor from the 'delta' parameter and multiplies the camera's height field by this scale factor.

See Also