Walkthroughs

=  a camera that follows a path that you define; the path comprises frames and key frames.

*Key frame = a modifiable frame where you can change the direction and position of the camera. Each click results in a key frame.

By default, walkthroughs are created as a series of perspective views (but can also create as orthographic 3D views).

1. Open a view in which to place the walkthrough path (usually a floor plan but can also make in 3D, elevation and section views).
2. ViewCreate 3D (Walkthrough).
3. [If wanting an orthogonal 3D view instead of perspective, clear the Perspective option on the Options Bar, and select a view scale.
4. If in plan view, can vary camera height by offsetting it from a selected level (can give effect of camera is going up/down a flight of stairs).
5. Place the cursor in a view, and click to place a key frame*.
6. Move the cursor in the desired direction to draw the path.
7. Click again to place another key frame.
• You can place key frames anywhere, but you cannot change their position during creation of the path.
• You can edit the key frames after you finish the path.
8. To finish the walkthrough path, you can do any of the following:
• Click Finish Walkthrough.
• Double-click
• Esc.

After you finish placing camera key frames, Revit creates a walkthrough view under the Walkthroughs heading in the Project Browser. 

Editing a Path

1. Similar to editing perspectives - Project Browser, right-click the walkthrough view name, and select Show Camera.
2. To move the entire walkthrough path, drag the path to the desired location.
3. To edit the path: Modify | Cameras tabWalkthrough panel(Edit Walkthrough).
• You can select which control in the path you want to edit from the drop-down menu.
• Controls affect the position and direction of the camera
• 
  

NB. the closer the points are, the slower the video will be between the points (the further away, the quicker) so bear this in mind - best to keep them relatively evenly spaced.

Dragging the Camera to a New Frame

1. For Controls, select Active Camera.
2. Drag the camera along the path to the desired frame or key frame. The camera snaps to key frames. (Or type the frame number in the Frame text box).
3. While the camera is active and located at a key frame, you can drag the target point of the camera and the far clip plane.

Changing the Path

1. For Controls, select Path. The key frames become controls along the path.
2. Drag a key frame to the desired location. Notice that the value in the Frame text box stays constant.

Adding/Removing Key Frames

1. For Controls, select Add Key Frame or Remove Key Frame.
2. Place the cursor along the path, and click to add/remove a key frame.  

Displaying the Walkthrough View when Editing

As you edit a walkthrough path, you may want to see the results of your changes on the actual view. To open the walkthrough view, click Modify | Cameras Walkthrough (Open Walkthrough).

Editing Frames

1. Open the walkthrough
2. Modify | CamerasWalkthrough(Edit Walkthrough).
3. Options Bar, click Walkthrough frame edit button .
4. The Walkthrough Frames dialog has 5 columns that show the frame properties:
•  Key Frame column - total number of key frames in the path. Click a key frame number to display where that key frame appears on the walkthrough path. A camera icon displays at the selected key frame.
• Frame column -  the frame at which the key frame displays.
• Accelerator column -  numerical controls for changing the speed of the walkthrough playback at a specific key frame.
• By default, there is a uniform speed at which the camera travels along the entire walkthrough path. You can change the speed by increasing or decreasing the total number of frames or by increasing or decreasing the number of frames per second. Enter the desired value for either
• To change the accelerator value for key frames, clear the Uniform Speed check box, and enter a value for the desired key frame in the Accelerator column. Valid values for the Accelerator are between 0.1 and 10.
• Speed column - speed at which the camera travels along the path at each key frame.
• Elapsed Time - the amount of time that has elapsed since the first key frame. 

Cameras Along Path

To help you visualize the distribution of frames along the walkthrough path, select Indicators. Enter a value for the increment at which you want to see camera indicators.

Resetting Target Points

You can move the position of the camera's target point at a key frame, for example, to create the effect that the camera is looking side to side. To reset the target points back to following the path, click Modify | CamerasWalkthrough (Reset Cameras).

see also http://www.youtube.com/watch?v=pGZmtRoXzjM

 Exporting

You can export to an AVI or image file. When you export a walkthrough to an image file, each frame of the walkthrough is saved as an individual file. You can export all frames or a range of frames.

To export a walkthrough:

1. Open the walkthrough view.
2. Click ExportImages and AnimationsWalkthrough. The Length/Format dialog opens.
3. Under Output Length, specify:
   • All frames to include all frames in the output file(s).
   • Frame range to export only a specific range of frames. For this option, enter the frame range in the entry boxes.
   • Frames/second. As you change the number of frames per second, the total time automatically updates.
4. Under Format, specify Visual Style, Dimensions and Zoom to the desired values.
5. OK.
6. Accept the default output file name and path, or enter a new name.
7. Select the file type, either AVI or an image file (JPEG, TIFF, BMP, or PNG).
8. Save.
9. In the Video Compression dialog, choose a video compressor from the list of compressors you have installed on your computer.
10. To stop recording the AVI file, click Cancel next to the progress indicator at the bottom of the screen or press Esc.

Rendering...

It is better to render the images, or individual frames of the walk-through, out to a JPEG or TIFF format.

Then use video-editing software to put all of the frames together into a video format. The human eye sees up to 30 frames per second; therefore, you should set your walkthrough's frame rate to 30 frames per second. This means a one-minute walkthrough will contain 1,800 still frame images.

If you render the walkthrough direct to a MPEG, AVI or other video format, you run the risk of the walkthrough getting an error before the walkthrough video finishes rendering. If this happens, the rendered walkthrough video will be corrupt and will not play.

OR JUST DONT RENDER...perhaps just have a nice render for the final image or the very first one...

Read more: http://www.ehow.com/how_8590258_create-walkthrough-revit.html#ixzz2gcE03nUK

http://whatrevitwants.blogspot.co.nz/2010/02/how-to-create-revit-walkthrough-and.html

https://www.youtube.com/watch?v=ijfjldYSqYg
https://www.youtube.com/watch?v=yrcdKOG7ti8 - making horizontal modifications (eg. the path)
https://www.youtube.com/watch?v=fyaSMF0bkEQ - making modifications in elevation (ie. easier way to visualise the heights of the camera particularly if using stairs)
https://www.youtube.com/watch?v=P_SSihizZ4U - more vertical modifications, using a different elevation view
https://www.youtube.com/watch?v=WfkEOI7QuR0 - some more editing, rendering
https://www.youtube.com/watch?v=_ynbo7j0i-8 - extending the path