Before you start planning your first motion capture venture, you should be familiar with the basic
process to optimize your planning and avoid disappointments (be absolutely sure not to miss the
MoCap production process is as follows.
1. The Planning Phase
You should clearly identify what you want to achieve. Ideally, you would record a video from multiple angles on DV cameras. Then you would contact us and our production manager will work with you to ensure that everything goes smoothly.
- Be careful that your expectations don't exceed the limitations of the MoCap equipment, otherwise captured data may be harder to process. This means that number of actors and other objects recorded at once is limited – not because of limitations, caused by hardware, rather because markers tend to overlap or hide from the cameras and the motion might be impossible to reconstruct from the captured data.
- Your performance must fit to the dimensions of the capture stage, e.g. if you want to capture a dancing pair, the choreography must be modified to ensure the dancers won't dance off the MoCap stage.
- Import data format – we have to ensure there is a way to transfer the data to your target 3D application.
- (optional) Skeletons for requested objects are discussed. If you want us to provide animated skeletons and not just raw marker data, both parties must agree on an appropriate skeleton layout. Your designer creates a CGI character, creates its skeleton, skins it (attaches character's body to the bones) and this data is a input for us. However, we have to check that the skeletons you provide are compatible with our tools.
- Dates, deadlines and pricing shall be discussed.
- Clients are welcome to visit prior to capturing to have a better idea how things look.
- For longer projects, we will book a hotel for you and offer other full service options.
2. Capturing the Motion
Normally, our project engineer co-directs the cast and crew together with our clients director so that everything runs smoothly, no special technical knowledge is expected from either your cast or director. Your director will instruct the actors to make the moves needed and aesthetically overlook the performance. Our engineer makes sure the recorded data is usable.
- Our staff is English speaking and very responsive. Don't worry about the technology itself, that is our problem.
- Catering can be made available on location otherwise three restaurants are in close vicinity of the studio. Arrangements can be negotiated for multiple-day projects.
- A typical working day consists of two ~ 4 hour sessions with a ½ hour to 1 hour break for lunch. MoCap is very intensive and under ideal circumstances things progress very quickly.
- All the cast should wear dark, non-reflective, tight-fitting suits to improve the MoCap cameras’ output. We have and provide special suits for this purpose. Actors need their own pair of shoes, however!
- On the client’s request, we can record the performance on multiple DV cameras, for reference purposes so that you more easily process the animations later.
- Recording is a real-time operation, think of the whole MoCap system like a large video camera, it can be turned on and off, bad takes can be deleted, each take is labelled either sequentially or as our client wishes.
3. Processing the Captured Data
Now that the data is captured, our operator processes it. This step must be done here in BIS using special software. We label the markers so that the following software systems understand which marker belongs to what part of the actor's body, then (optionally) even animated skeleton is calculated from the markers' motion.
MoCap data processing – required
- If the markers were connected directly to the bones, it would make our lives much easier. In reality, the markers lay on top of muscles which change their volume with each move and also are off-axis from the bone itself.
- MoCap cameras emit normal light, not X-rays, so if the actor blocks any marker from all the cameras, its trajectory must be reconstructed using information from other markers. Some moves, especially falls, are harder to process because of that.
- Also, inevitable noise inherent to every electrical device must be filtered out.
- The result of the data processing is each trajectory of every marker recorded on place has its own corresponding name and is free of possible gaps or spikes
Motion Builder: Actor mapping
Once marker trajectories are processed and available, the data may be mapped onto a standard puppet "Actor" in Autodesk MotionBuilder. This is what most clients want us to do, we provide data in FBX with actors already mapped. It is most comfortable and fast way to start working with the recorded data - everything mocap-specific is effectively hidden to the client, who only concentrates on animating with their target CG characters.
Motion Builder: Retargeting – optional, recommended for 3DS Max users
The movement data can be then retargetted to actual skeleton structures of Your CG character. If the CGI character has different proportions than the human actor (which is usually the case), the moves must be transplanted to another body with different bone sizes. The more the source and target skeletons differ, the more complications are likely to occur.
This is a bit tricky and rather artistic than technical task for the first time in mocap processing pipeline. That is why we recommend that client's animators who work on final moves actually do this step themselves as they better know what they are trying to achieve and adjust retargeting settings to their needs. With one exception: users of 3DS Max Character studio will likely need us retarget: optical data handling in 3DS Max is rather problematic, depends on specific markersets, which are hard to work with in real world.
The move data is exported in the appropriate format and passed to the client's operators for further processing, unless complete manual editing is requested by the client.
Generally, post-processing and above all additional tweaking is a much more difficult task than the capturing itself, please take this into account. One day of MoCap data may take one animator even 2-4 months to perfectly "polish"! However, the reward is very realistic animation that can't reasonably be reached any other way.
The output data from the MC pipeline – your options
- edited labelled trajectories - for general use - complete trajectories of the markers for use in rigs in MotionBuilder, Maya etc.
- motion data mapped on Actor puppet for MotionBuilder - typical - for full body moves for use exclusively in Autodesk MotionBuilder. This is most comfortable way to quickly start working on actual move data and typical choice.
- direct animated CGI skeleton - for skeletons importable into MotionBuilder, we can perform retargetting here and provide client with either retargeted or even final animated skeleton. This is a choice for users of 3DS Max's Character studio.
Be sure to see available file formats!
Checklist – what rather !not to forget!
- choose right actors. Men can't reasonably substitute women, weak person hardly can double strong trained expert when fencing and so on. The character of the move is really preserved till final animation, so what they perform is what you get - do not underestimate that!
- actors must have their own shoes adequate to the action they'll perform (e.g. a heel? Or trekking shoes?), markers will be attached using a adhesive tape that will be removed after the session is over.
- have list of moves to be recorded ready, also one extra copy for MC engineer with move names - filenames will be based on this document. Either printed or as a XLS sheet on a CD/DVD or flash disk, please. Sort moves to groups with same actors and/or props, also moves with a risk of damaging markers by a contact with a floor, collisions etc. should be recorded in the end of the session.
- should the moves occupy larger area, think about dividing the action in more simpler moves occupying less space. The moves will be connected in post-processing together - if unsure, please talk to us, we will help.
- arrange a rehearsal prior the recording itself to make sure actors learn what you expect them to do.
- bring DV camera with a tripod to the studio to record reference video for your animators. Or let us know and we will arrange one.
- need props, e.g. swords, guns, staffs..? Do not forget to bring these or discuss this with us in advance!
- Need accomodation? Book yourself or let us book rooms for you.