by Brian Immel
In this tutorial, we will cover concepts used to rotoscoping animation from live-action footage. We will use a firewire-enable camcorder, Adobe Premiere (version 5.5 or later) and Alias Maya (version 4.5 or later).
To see the reference image, click on the linked figure number. To return to your previous instruction line, click on the figure image.
What you will need:
- Big open space
- No visual distractions (highways in the background, tall grass, tree limbs, office furniture, etc.)
- Good weather conditions (if working outdoors). Preferably a good sunny or slightly overcast afternoon.
- Steady tripod
- DV Camcorder
- If you are working alone, use a camcorder that allows for a swivel screen
- 256MB of RAM, 512 is better but 1GB of RAM is best
- 40GB+ 7200rpm Hard drive (120GB should do the job just fine)
- CD or DVD burner to archive your motion clips
- Firewire card
- Video card that can handle 3D applications (anything from Nvidia will work great)
- Adobe Premiere (version 5.5 or better)
- 3D application (in this case Maya)
Time Stamped DV tapes
Before shooting, make sure your tape has been time stamped (blacked out).
When capturing footage, it is very important to have the tape time stamped.
Premiere reads the time stamp in a linear fashion. If you have not blacked
out the tape, each time you remove the DV tape from the camcorder or shut
it off, a new time stamp is made when you start recording again. Premiere
will get confused over which time stamp to follow when you are capturing
the footage. If you time stamped the entire tape, the camcorder will not
rewrite the time stamp every time you turn the camera on/off or remove
the tape repeatedly.
To black out a tape, put the DV tape in the camera, leave the lens on, and disable the microphone. Hit the record button and let the camcorder roll until the tape has recorded 60 minutes of complete black and silence. Rewind the tape and mark it so that you know you time stamped this tape. I usually write TS in the corner of the top label or make a little box and fill it in.
Acting Area (Stage)
Clear your area of any visual impairment. This includes foreground elements (things that get in between your motion actor and the camera lens), excessively busy background elements (highway travel, extras (children in the background), and middle ground elements (tall grass, big tree limbs, etc.). Keep the camera frame open so we don't have to guess where to stop and need to do some unnecessary editing or lose a good take.
Place markers in your ‘acting area’ to give you an idea of your stage. Look through the viewfinder and place strips of tape or some sort of marker on the ground. You don’t want to be acting outside your camera’s visual range. If possible and you are working outside, use a basketball or tennis court. These areas are usually marked well and are great for shooting because they are clean, level and free of debris.
Shoot a placement shot to test the distance of the camera and mark the location with tape (indoors) or tree limbs (outdoors) so you have a reference to where your shooting range will be.
Practice your motion(s) at least 2-3 times before shooting. Get an idea of what, when, and where things happen. Do you need to hit a mark at a certain time? Where are your arms and legs in relation to the camera’s lens?
Review your storyboards. What do they tell you to do? When do you need to complete an action? How do they tell you to complete the action?
Use straight-on angles to start with (Figure #). Try to avoid moving at an angle to the camera. This will make the rotoscoping process difficult. If you must move at angle to the camera, shoot multiple takes of the action with multiple angles.
Tape pre-roll: Start recording and let the tape roll for a few seconds before you start your motions. Let the pre-roll go for a minimum of 10 seconds if it’s at the beginning of the tape, everything else can have a pre-roll of 3 seconds. The reason we need this pre-roll is purely a digital reason. Adobe Premiere needs at least a few seconds to cue up the tape to proper location to start capturing information. If we don’t give it enough pre-roll, you might cut off some of those precious moments we have been trying to capture. Don’t worry about the length of the pre-rolls eating up your tape time. You will burn up more tape with takes and retakes more than anything else.
Shoot at least three takes of each motion. Sometimes, we know the motion we want to capture but don't know quite how to act it out. Other times, we get a little self-conscious (even though no one is around) and this will mess up your performance.
Tape post-roll: Let the tape roll a few seconds after you’ve finished your motions.
Review the footage on-site. Look for mistakes, cutting your head, legs, arms out the shot, missed cues, good timing and placement. It is better now to look for mistakes than to try to sort them out on the computer later when you don’t have access to that open space again.
The next step in this process is to set up your computer, camcorder and Adobe’s Premiere for capturing the footage. This step isn’t as difficult as it may seem but problems may arise if your camcorder is not capable with Premiere’s DV Device Manager and/or your hard drive is slower than 7200rpm. The hard drive speed is important because there is were the ‘dropped frames’ problem comes from usually.
- Connecting the camcorder to the Premiere
- Identifying the firewire cable needs
- 4-6 pin
- 4-4 pin
- Identifying the firewire cable needs
- Connect the firewire cable from the camcorder to the computer’s firewire port.
- Power up the camcorder and turn it on to VCR or VRT mode (whichever is used to treat the camcorder as a VCR). When we are in Premiere and everything is set up properly, we can control the camcorder remotely via Premiere. At this point, you may want to use a power supply that is not battery dependant. Most camcorders have a built in feature that turns off the camera or goes to sleep after a few minutes of being idle. This will disconnect the communication between Premiere and the camcorder. But most camcorders that are powered by electrical outlet means usually disable the sleep mode.
- Place DVcam tape in the camcorder.
- Start Premiere. The camcorder must be connected to the computer by the firewire, powered and in VCR mode before starting Premiere. When Premiere starts, it looks for connected devices such as firewire-enabled camcorders. If you don’t follow these steps in order prior to starting the program, then Premiere won’t detect the connected devices.
- Configure Premiere to read the information from the DV device if necessary. Use the DV Device Manager Editor to configure Premiere.
Now that we have everything hooked up, we are ready to digitize the footage we shot.
- File > Capture > Movie Capture. This will open the Movie Capture window.
- Hit the play button and use the scrub bar to move forward and backward through the footage. Scrub through the footage a few times to get a good feel for what parts of the footage is usable and what is not. Review the tape to a few seconds before the clip you want to capture.
- Hit the Set In button to mark the ‘In’ location of the clip.
- Hit play and let the tape roll until a few seconds after the section you want to capture of the clip. Hit the Set Out button to mark the ‘Out’ location of the clip.
- If you are only capturing a single clip, hit the Capture In/Out button. Premiere will automatically rewind the tape and cue up the tape and record the footage defined between the In and Out marks. After Premiere is done capturing the clip, the File Name window pops up asking you to name the clip and add any Log Comments. Name the clip and hit Ok.
- If you are capturing multiple clips, hit the Log In/Out button. The File Name window pops up asking you to name the clip. After naming the clip and hitting Ok, The Batch Capture window pops up. Repeat this process until you have logged all the In and Out points of all the clips you wish to capture. Once you have logged the clips, hit the Record button (red button in the Batch Capture window). Premiere will automatically rewind and cue up the tape to each clip and capture all logged clips. This may take a few moments depending on how many clips and the length of the clips. Lunch break!
When exporting the movie, you may want to modify the output size if you are on a slower computer. Clip areas of the footage that are not used. For example, if you motion actor never leaves the center of the frame, you can clip the sides off and reduce the file size greatly.
Use only formats that are supported by the software you will be using this footage in Maya like uncompressed .AVIs, image sequences (Targa, Tiff, Jpeg, Bitmaps). I don't use the latter two because they are a lossy format. You can use image sequences, but I would not recommend it (Figure #). Setting Maya up to receive image sequences is more complicated than necessary in comparison to using a movie clip.
If you are not capturing facial animation or the clip you are going to animate is not sound dependant, disable the audio export option as well.
- The first thing we want to do in Maya is make sure the program is set up for rotoscoping animation. Playback should be set to 30fps and set the undo limits to Unlimited. To change your playback settings, go to Window > Settings/Preferences > Preferences. Click on the Settings Category and make sure that Time says NTSC (30 fps). While the Preferences window is still open, go to the Undo Category and set the Undo options to Undo = On and Queue = Infinite. Setting the Queue to Infinite will require more memory but its better to have the option to back out of something if necessary rather than having to restart the file again and again.
- Turn on Texture view in the persp viewport (keyboard shortcut 6).
- Create a NURBS plane with the portions of the footage. Since this is a PC and a DV format image file, the movie file’s dimensions should be 720 x 486 unless you modified the output size. The image plane should have the same ratio as the movie clip. To make the image size more manageable in Maya, divide the width and height by 100. Create a plane and set the ScaleX to the width of the clip divided by 100. Set the ScaleZ to the height of the clip divided by 100. Don’t worry about the size of the image plane in relation to the character just yet.
- Name this plane reference plane. Put this plane in a layer and name the layer Reference.
- Rotate the reference plane so that it sits upright and parallel to your character.
- Create and link a new Lambert shader to the reference plane.
- Link the footage to the color attribute of the shader via a movie file.
- Maya will create a node labeled movie1. Click the folder icon and select the clip and hit Open.
- We now see the first frame of the clip but if you scrub through the timeline at this point, you will not see the footage update. We need to tell Maya to display each frame of the clip. Enable Use Frame Extension in the Attribute Editor of the movie1 node.
- Next we need to tell the Frame Extension to update every frame when we slide through the Time Range. We can either set keyframes on the Frame Extension to mark the beginning and end of the clip or use a simple expression. Right-click and hold on the attribute Frame Extension and go to Create New Expression.
- In the Expression window of the Expression Editor, type in the following expression: movie1.frameExtension=frame
- Hit Create and close the Expression Editor. Replace movie1 with the name of movie file node if it is not named movie1.
- Rescale the surface uniformly to match the size of your character. For example, I'm 6' tall guy and my character is about 3.4cm. The reference plane is a relative instrument that we can use to better suit the CG character. I guess what I'm trying to say is that it is a lot easier to resize a single plane than an entire character rig and surface.
- Position the reference plane behind the character. Match up the angle you shot with on the camcorder.
- Turn the on the Reference mode for the Reference layer once you are done scaling and placing the reference plane. Referencing this layer prevents you from accidentally selecting and moving the reference plane.
Keep in mind the whole reason for shooting the footage was to have a reference for your animation, not a final answer to how it should look and feel.
Apply the principles of animation where they are needed. Remember the twelve principles of animation your teacher rammed down your throat when you were first learning animation? Well, use what you need, not all of them!
Find the major and minor poses in the footage and create key poses with your character to match. Don't worry about the inbetweens just yet. Keyframe the body first, then the feet, arms, neck/head and the fingers last.
Use the Graph Editor to modify the animation curves to adjust the ease in and ease out of some of the motions.
Adjust the timing of the animation once you have completed the sequence. Use the Dope Sheet for major changes in timing but use the graph editor for minor changes.
Playblast everything after the major edits have been made. Depending on how fast your computer is, your playback speed will not give you a true representation of the timing or speed of the motion. Remember you are translating motion information for a 2D image that may have different portions from your virtual actor to the actual actor.
Animate beyond the second dimension! If you recall, this animation is based off of a 2D image plane and you will not have some motion information because of the angle(s) of the character to your performer. You won't always have the visual information of where the actor's opposite arm is sitting. You may remember but where but do you remember the timing of where it was at and when?
Adlib a bit from time to time. Give your virtual actor a little more action than what the actual taped performance did.
The graph editor is your friend. Use it wisely and often! This is where the majority of the animation cleanup will take place.
Build yourself a library of motion. Videotape people walking, talking, animals running about and playing. DV tapes are relatively cheap nowadays and hard drives are getting bigger and bigger all the time while the prices is dropping. Building a library can save you some time and money in the long run.