Recording Video from Depth Sensor
- 1 Environment
- 2 Actor Clothing
- 3 Recording Process
- 4 Recording Actor's Performance
Minimum space requirements for depth sensor configurations depend on sensor model and number of sensors:
|Configuration||Kinect 2 (Kinect for Xbox One)||Kinect|
|Single Depth Sensor||
8 by 5 feet = 2.5 by 1.5 meters
10 by 10 feet = 3.0 by 3.0 meters
|2 Depth Sensors||
8 by 8 feet = 2.5 by 2.5 meters
10 by 10 feet = 3.0 by 3.0 meters
|3+ Depth Sensors||
16 by 16 feet = 5 by 5 meters
20 by 20 feet = 6 by 6 meters
Maximum capture area is about 7 by 7 feet ( = 2 by 2 meters), for all sensor models and configurations.
It is convenient to put MS Kinect Sensor on a chair or a table. The picture below will help you to understand possible capture area and required space. Dimensions are different for Kinect and Kinect 2 (Kinect for Xbox One) sensors due to different field of view.
Kinect 2 for Windows and Kinect for Xbox One
Kinect 2 (Kinect for Xbox One) sensors have wider angle of view compared to first generation Kinect. This makes possible to come closer to sensor thus decreasing overall space requirements.
First Generation Kinect
Current version uses only depth information to track motions. So clothes requirements are:
- no restrictions on clothes colors (just avoid shiny fabrics)
- please use slim clothes to reduce noise in resulted animation
iPi Recorder is a stand-alone application and does not require a powerful video card. You may choose to install it on a notebook PC for portability. Since it is free, you can install it on as many computers as you need.
Please run iPi Recorder and follow recording workflow as described in user's guide for the program.
Recording Actor's Performance
After completing Setup and Background recording steps, press Record button to begin video recording. To stop recording, press Stop button.
Recommended Layout of an Action Video
- Enter the actor.
- Strike a T-pose.
As soon as recorder starts, go to the capture area and stand in a T-pose. After that you can act desired motions.
If you make several takes of one actor, we recommend to strike a T-pose in the beginning of each take.
Take is a concept originating from cinematography. In a nutshell, take is a single continuous recorded performance.
Usually it is a good idea to record multiple takes of the same motion, because a lot of things can go wrong for purely artistic reasons.
A common problem with motion capture is “clipping” in resulting 3D character animation. For example, arms entering the body of animated computer-generated character. Many CG characters have various items and attachments like a bullet-proof vest, a fantasy armor or a helmet. It can be easy for an actor to forget about the shape of the CG model.
For this reason, you may need to schedule more than one motion capture session for the same motions. Recommended approach is:
- Record the videos
- Process the videos in iPi Mocap Studio
- Import your target character into iPi Mocap Studio and review the resulting animation
- Give feedback to the actor
- Schedule another motion capture session if needed
Ian Chisholm's hints on motion capture
Ian Chisholm is a machinima director and actor and the creator of critically acclaimed Clear Skies machinima series. Below are some hints from his motion capture guide based on his experience with motion capture for Clear Skies III.
Three handy hints for acting out mocap:
- Don’t weave and bob around like you’re in a normal conversation – it looks terrible when finally onscreen. You need to be fairly (but not completely) static when acting.
- If you are recording several lines in one go, make sure you have lead in and lead out between each one, i.e. stand still! Otherwise, the motions blend into each other and it’s hard to pick a start and end point for each take.
- Stand a bit like a gorilla – have your arms out from your sides:
Well, obviously not quite that much. But anyway, if you don’t, you’ll find the arms clip slightly into the models and they look daft.
If you have a lot of capture to do, you need to strike a balance between short and long recordings. Aim for 30 seconds to 2 minutes. Too long is a pain to work on later due to the fiddlyness of setting up takes, and too short means you are forever setting up T-poses.
Because motion capture is not a perfect art, and neither is acting, it’s best to perform multiple takes. I found that three was the best amount for most motion capture. Take less if it’s a basic move, take more if it’s complex and needs to be more accurate. It will make life easier for you in the processing stage if you signal the break between takes – I did this by reaching out one arm and holding up fingers to show which take it was.
As it’s the same actor looking exactly the same each and every time, and there is no sound, and the capture is in lowres 320*200, you really need to name the files very clearly so that you later know which act, scene, character, and line(s) the capture is for.
My naming convention was based on act, scene, character, page number of the scene, line number, and take number. You end up with something unpleasant to read like A3S1_JR_P2_L41_t3 but it’s essential when you’ve got 1500 actions to record.