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Building Virtual Camera Rigs with Vicon Mo-Cap

Asa Bailey Vcam

Shooting fully virtual, in-engine is one of the most liberating ways to shoot. Instead of the usual metal seen on any other shoot, there’s no real camera. We use a tethered simul-cam or virtual camera rig, built using an ATOMOS for both view-finder and as an onboard recorder. When we see the shot we want we simply press record on the camera’s recorder and we capture the shot, in real-time. Thanks to the way the GODBOX Real-time Ready architecture works, there’s almost no delay between the virtual camera rig’s operator moves and what’s recorded on the drive. Optical motion capture technology is not cheep, it’s certainly a professional mo-cap solution including all the Vicon cameras (6 VARO 2) a set of passive / active markers and the VICON Shogun software.

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Setting up the pipeline, the art is in the set up.

As we’ve found with all VP kit it’s never a case of turn it on and off you go. The Vicon is the best motion capture system we’ve used, it is accurate and paired with the GODBOX On-Set Workstation, it’s also the fastest in terms of low-latency. But a bit like the Ncam and the Mo-Sys, its the operator and their experience in ‘nurturing’ these systems that makes them really sing, and more importantly stable for any production. Sleep with your gun, these systems take time to master. But when you do, when you have a solid hands on skill in a number of camera tracking systems, there wont be many situations you won’t have an answer for.

We pipe the Vicon’s tracking out-put into Unreal. Balancing out the initial configuration of your cameras and markers in Shogun is key to this working, do that before rushing into UE, make sure your Vicon system is happy then get into UE. If you know your set up is solid in terms of your computing and in terms of your mo-cap system all running smoothly, if you encounter framerate or data jitters in UE, you can be almost certain it’s your UE set-up; maybe even your level that is giving you problems. We can never stress enough the importance of level optimization and a staged process of checks as you build your pipeline. We always aim for final pixels even if we are shooting pre-viz, and even the smallest frame glitch can ruin a real-time in-engine shot. But the beauty is, if your engine operator hit record on the Take Recorder too, then hopefully you can simply run off another take of your camera move, from in-engine.

The hardware part is, a GODBOX real-time ready PC, a modest VICON set-up for camera tracking, with HUB etc., some camera rails and handles, add in the ATOMOS Shogun HDRI recorder and some SDI cables for your loom, a battery.

Lets talk about camera crowns for a moment, we tried all sorts of designs and really went to town on testing both active and passive markers with the Vicon system. Which is best active or passive, sorry, that’s also not a simple one or the other question. It dependent on the camera moves and the size the volume to be tracked, how its lit, and even if practice effects are involved, we’d suggest you hire a motion-capture or professional camera tracking team for any real-production advice. But for starting off and getting going – get both. A set of active and a set of passive markets will help you learn how they differ. What about the number of markers to add to your camera crown? Again this can be different depending on the production environment, to start with try 5 or 6, set on the ends of small rig tubes in our case.

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