Maya Architectural Walkthroughs

When planning walkthroughs you need to remember some important pointers.

Don’t run through the building with your camera, people will miss some detail of the room and need to rewind to look at it again.
Don’t turn too quickly as you cause nausea in your audience.
Do not walk back out the way you came with the camera, people have already seen this part and it doesn’t look professional.
A good way to create the walkthrough is to create a series of 5 second renders and edit them using Premiere or After Effects using simple fades. Have the camera in a corner of the room and turn slowly to capture the scene of the room over the 5 seconds.

Animation of Cameras

There are several ways you can animate the path of a camera. Some common techniques in Maya include;
1) Standard Keying of the camera’s shape node parameters
2) Motion Paths
3) Layered motion paths with aim constraints.

Standard keyframed animation is a bit clumsy for this kind of work so we will focus on the latter two animation styles.

Path animation

A path animation controls the position and rotation of a camera along a curve. For a NURBS curve to become a path curve a camera must first be attached to the curve.

Creating a motion path by attaching a camera to a curve.

1) Create a NURBS curve.
The curve is the path along which the object moves. The direction you create the curve is the direction the object moves.

2) Select the camera you want to animate on the path, and then Shift+select the curve.
Note: You can animate many objects along the same path curve by first selecting the objects, and then selecting the curve. You must select the curve to be used as the path curve last.

3) Select Animate > Motion Paths > Attach to Motion Path
In the options dialog choose Edit > Reset Settings, then click Attach.

The object moves to the point on the curve where it is positioned for the current time. Also, two motion path markers with numbers appear at each end of the curve. These markers indicate the position and time at which the object moves to those marker positions.

4) To view the animation of the object, click the Play button in the Playback controls.

Note that the camera does not aim along the curve

To change this we will need to first find out the local axis for which the camera is pointing

1)      Select the camera

2)      Display its object rotation axes: we see that that camera aims along the - Z axis

3)      Select the path, then open its Attributes (CTRL-A)
       a.       Change the front axis to match (Z axis)
       b.       Check "Inverse Front"

Now the camera follows the path in the right direction.

Controlling Flow along the path curve using Motion Path Markers.

Currently the camera travels from the beginning of the path curve to the end of the path curve over the time period covered in the time slider.  Note that there are dark green markers at the beginning and end of the curve.  These are called Motion Path Markers.  They specify where the object on the motion path will be at a given time.  For example the camera will arrive at the point of motion path marker “250” at time 250.  Currently there are only two markers: at the beginning and the end.

Adding Path Markers If you select the camera and then click the show manipulator tool (hotkey T) you will see both a set of three rotation axes appear around the camera as well as a small yellow square.  Middle mouse click the yellow square and notice how you can change the position of the camera along the motion path If you open the inputs to the camera you will see one called “motionPath1”: open it and notice that the movement of the yellow square changes the “U Value” of the motion path. Move the time slider to about half way and then set a key for the U Value (Select U Value in the channel bar and right click > Key Selected).  You will see that when you set a key you also create a path marker. Modifying Path Markers. The movement of our path is at the moment linear.  We can change this using U Value. Start by moving to say frame 40 on the time line: the camera will also move to where it should be at time 40.Now select the camera and open its input motionPath1 and change the U Value to say 0.75 (or slide the camera along the path using the middle mouse button) and set a key for the U Value.

Note that now the path marker “40” moves to where the camera was.  Now rewind the animation and note that the camera moves quickly until the 40 marker then slowly for the rest of the time slider. You can set as many path markers as you think are necessary but don’t go overboard, keep your animation points to a minimum.

Adjusting the quality of movement using the Graph Editor

The nature of the path markers can be seen visually in the graph editor.  1)      Open the Graph Editor (Window > Animation Editors > Graph Editor). 2)      Back in the Perspective View, select the Motion Path 3)      Select its Inputs You should now see the curve of the U Value with the three keys set. Note about Curve Tangency.          For walkthroughs you always want to have very smooth camera work          The best kind way to achieve this is through the use of flat and spline tangents

The motion path curve with default tangents	The motion path curve with shaped splines and flat tangents to end camera movements

To change the tangency of a keyed point in the Graph Editor select the key and right click > Tangents > Flat.

Controlling the local rotation motion of the camera along the motion path.

 Besides being able to key the position of the camera along the motion curve over time, we can also key its local rotation axes.

Select the Camera and open its input motionPath1

Notice that there are controls for
         Front twist
         Up twist
         Side twist

You can change these values numerically, but it is more intuitive to use the manipulator tool.

Click show manipulator (hotkey T) and select the camera.  Middle mouse click and drag on the different rotation axes and notice how each one controls the three twist controls respectively.

Exercise

Create a roller coaster-cam ride

         Create the motion path for the roller coaster
         Modify the U value such that there is the feeling of gravity: free fall and slow climbing
         Animate the tilting of the carriage using the twist controls.

Architectural Camera Shot Styles