The Comparative View Inspector window can be turned on from the File menu and by default will appear to the left of the View Manager and below the Object Inspector. The render view in the View Manager must be converted to one of the Comparative views, otherwise the inspector remains grayed out. For the examples below we will use the 3D View (Comparative) setting.
The Properties section is used to control the type and size of the study. Two Modes are available; Film Strip and Comparative. In the Film Strip mode a single parameter changes in the frames, starting at the top left view and moving across and down to the bottom right view. In the Comparative mode two parameters can change, one along the X axis (across) and one along the Y axis (down). The parameters can be from the same object or from two different objects.
The Number of X Frames determines the number of fields visible from left to right, and the Number of Y Frames sets the number of fields from top to bottom.
The Update Mode determines how updates are handled. There are three options; None, Root and All. When None is selected, the frames will not update until the Update button is pressed. The Root option causes the root frame (top left) to update immediately, but all other frames will update only when the Update button is pressed. With the All option, all frames will update when a change is made without the use of the Update button.
The Show timesteps checkbox toggles the use of the global time. When unchecked, the global time is displayed in each frame. When checked, the global time is ignored and different timesteps are show in each frame.
The Animated Source (X Axis) contains two fields, Selected Object and Property to Animate. First select the object from the drop-down, then the property that will change in the views. If the Film Strip mode is used, this is the only source selection available and the changes will start in the top left view and move across and down to the bottom right view. For the Comparative mode, this section defines the property that will change going from left to right in the views.
An Animated Source (Y Axis) section appears if the Comparative mode is selected, and is used to set the object and property that will change going from the top view to the bottom.
The Track section defines the property limits. When the X Axis (and possible Y Axis) sections are filled in, the respective tracks appear. Double-clicking on the track opens the Comparative Visualization Keyframes window where the beginning and end values can be entered, and the interpolation can be changed if necessary. The beginning and end values will generate the views in the first and last frame respectively. Once the values are set, click on the Play button on the VCR Controls toolbar, and the settings will appear in the track.
The Update button at the bottom of the window will update the frames in the view. Depending on the size of the dataset(s), updating the views may take some time.
All the cameras are linked to the top left view (it is the only view that shows axes in the bottom left corner). Changing the viewpoint in this render view will apply the same change in all the other frames. The images below show the view along the positive Y axis.
The following image shows the frames generated when the Film Strip settings above are used to study the End Theta values between 30 and 360 degrees. The first frame is in the top left and then moves across and down, showing the last frame in the bottom right view. The first frame shows the sphere with End Theta at 30, and the last frame shows the sphere with End Theta at 360. The other frames are generated by dividing the changes into the number of available windows.
This image shows the frames generated when the Comparative settings shown above are used to study the End Theta along the X Axis and the End Phi along the Y Axis. So each row shows the same End Phi value but the End Theta increases moving to the right, and each column has the same End Theta value, but the End Phi increases from top to bottom. In the top left image, the End Theta equals 30 and End Phi equals 60, and in the bottom right image the End Theta is 360 and the End Phi is 180. The other frames are generated by dividing the changes into the number of available windows.
Caution: If the beginning and end values in the track cover a large range where not many obvious changes occur, and a low number of frames is used, the results may appear incorrect. For instance, in this example, a comparative study of a sphere is set up where the Phi Resolution changes on the X Axis from 3 to 100, and the Theta Resolution changes on the Y Axis from 3 to 100, using a 4 x 4 grid. At first glance, it appears that the application didn't correctly create the images from the property values.
There appear to be only four different images; the first frame, the rest of the first row, the rest of the first column, and then all the other frames. Adding the Annotate Time source shows that the time values do change, but since the visible resolution changes appear at low resolution values, they are not apparent in the comparative study.
You can check the images in the frames by re-creating a single image in a 3D view with the required values. In this case, the resolution changes from 3 to 100 within 4 frames (100 - 3 = 97, divided by 3 is approximately 32) so in frame 1 both resolutions are 3, and Theta remains at 3 across that first row of frames. Moving across to frame 2, Phi is now 35 (3 + 32), in frame 3 it is 67, and frame 4 is 100. Although the Phi Resolution changes by fairly large amounts, no visible change is apparent. The same applies to each column. Re-creating these images one at a time in a 3D view shows that the correct image is displayed.
To actually see the resolution changes in this comparative study, change the two end values to 10. Most of the visible changes appear at these lower settings, and the higher resolution just smoothes out the sphere.
Note: The Comparative View Inspector is still under development and may not always generate the expected output. When switching between the Film Strip and the Comparative mode, the tracks may disappear. To re-create the tracks, select a different property in the drop-down and then switch back to the property you want to animate. The track should appear, but the values will have to be entered again.