General Module Function
fly_through is an animation modules which facilitates controlling the Viewer or creating an animation in which the view follows a complex 3D path on, through, or around your model. The method by which this module controls fly-throughs allows the user to pause at any time and interact with the model using their mouse or the Az-El panel.
Az-El parameters (azimuth, elevation, scale, field of view, rotation/scaling center, etc.) are updated by fly_through in real time. This can be seen by running fly_through with the Az-El window open. However, please note that this will slow your animation substantially because of the need to continously update the parameters in Az-El.
Unlike this module's predecessors, there is no need to "reset" to a normal mode, as fly_through's normal mode of operation is identical to using Az-El with advanced centering options.
IMPORTANT NOTE: Be sure to TURN OFF "Animate Viewer" in the Animator module if you're controlling fly_through with the Animator.
Module Input Ports
fly_through has two input ports. The magenta port must be connected to the output port on the Viewer and the blue/black (field) accepts the output from any module with that can provide a polyline path. Examples of appropriate modules would be read_lines, draw_3D_lines, etc.
Module Output Ports
fly_through has two output ports. The blue/black (field) port outputs the subset and/or splined version of the input path. The red port connects to the Viewer to allow display of the subset and/or splined path.
Module Control Panel
The control panel for fly_through is shown in the figure above.
The Initialize button sets the viewer orientation to the beginning of the fly through. This should be pressed after all modules connections are made and a valid (flying) path input is supplied to the module. It can also be used to reset the position to the start of the specified Line Number.
The Step toggle advances one step along the fly-through path.
The Run toggle allows you to start and stop the fly-through animation. It is reset to off when it is finished.
The Cycle toggle allows your animation to rerun when it reaches the end. (keep running from beginning), If your path closes on itself this can make a continuous animation.
The Position slider determines the camera position along the length of the specified path. The value is updated during running of the module, but the user may jump to any point along the path part of the specified iteration by adjusting the position slider. This parameter may also be controlled using the Animator. Note: when controlling position with the Animator, only integer values apply. If you want an Animator driven animation with more steps than the specified number (default 500), you must adjust the Number of steps in path parameter in this module.
The Line Number type-in lets you specify which polyline segment to use. This is very useful since read_lines and other modules can have inputs which contain multiple paths.
The Number of steps in path: type-in lets you specify the total number of steps into which the polyline is divided. More steps result in a slower and smoother fly-through.
Spline Path is a toggle which controls whether the incoming path is splined before being subset into the specified number of steps. Unless you are smoothing or splining with polyline_spline this should normally be ON.
Visible is a toggle which controls the visibililty of the (splined) flight path if the red output port of fly_through is connected to the Viewer.
Perspective is a toggle turns perspective on or off. Fly-throughs generally must use perspective because without it there is no concept of distance from the camera to the objects in the Viewer.
Field of View is a slider that sets the total included angle (in degrees) of the camera lens used to see the scene. and perspective is based on the concept of a lens angle. Larger angles have a wider field of view. This parameter may also be controlled using the Animator.
Normalized Back off is a slider that sets a back-off distance between the point on your path and the camera. The units are dimensionless (not in your model units of feet or meters). This slider ranges from 0 to 20.0. In perspective view, back-off is similar to the inverse of scale. This parameter is only active when Perspective is selected and it has a noticable effect on the clipping planes. This parameter may also be controlled using the Animator.
Scale is a slider that is identical to the Scale in the Azimuth & Elevation panel. This slider ranges from 0.01 to 25.0. If the buttons on the Scale and Normalized Back Off sliders are in the same relative position, the apparent scale of the model is relatively unchanged, however the clipping and point of view is altered. This parameter may also be controlled using the Animator.
Sample Applications
A sample network that demonstrates the use of fly_through is fly_thru_full-site.v in the Pro folder. The applications is shown below:
{bmc fly_through_app.bmp)
In order to help users understand the basics of fly through animation, each modules function is summarized below.
Post_samples creates the display of the measured data. Any other objects such as plumes, slices, etc. could be added (though you would need to add Krig_3D to create a 3D volumetric model).
Axes provides annotation of the spatial extents.
Read_lines is used to read the 3D path which was previously drawn and saved with draw_3D_lines.
fly_through takes the output from read_lines and controls the Viewer's apparent camera position.
The Viewer window is shown below half way through the fly through.
