Review: iPi Desktop Motion Capture
It’s an affordable approach to motion capture, but can iPi Soft’s markerless solution, designed to work with relatively low-res cameras, revolutionise the industry?
Price: $995 | Developer: iPi Soft | Platform: Windows
- Uses webcam or digital cameras
- Offline processing
- Outputs BVH, Collada, SMD files
- No need for special clothing
Designed to work with relatively low-res cameras, the PlayStation Eye is recommended
Newcomer to the motion-capture market iPi Soft recently released its new markerless motion capture package. The system relies heavily on video footage (640×480 at 60fps is recommended) and analysis of a multi-camera shoot to provide a bipedal skeleton derived from the footage shot.
Setting up the system should have been easy, but sadly that was far from being the case: the supplied and recommended four PlayStation Eye cameras have no means of screwing onto a standard tripod thread mount.
This is an issue, as the fidelity of the data relies heavily on a good, stable calibration. While various workarounds are given on the iPi forums, we found our own solution by securing the cameras to the tripod head with cable ties.
At this point, however, it’s worth noting that iPi Soft only sells the motion-capture software; it’s up to you to provide the necessary cameras, tripods and cables, so ultimately the quality of the hardware setup is down to your own personal tastes and budget.
Slowly but surely
Once the system is set up, calibration relies on good camera placement and a modicum of patience. The process involves lining up the character in each camera, and then allowing the software to align the character to the person in the footage. It can take several attempts to get a good start position pose based on your footage.
Unlike traditional mocap, from a first-class facility like Centroid, or the affordable end-user markets such as OptiTrack or MVN systems, you don’t get a live preview. From a technical standpoint, having to wait for the system to track and solve the four cameras to deliver a skeleton with applied motion is quite time consuming, especially if you’re used to live previews.
The speed of the track and solve depends on the host machine’s speed, but the quad core system and Quadro GPU used for the review averaged seven seconds per frame – which isn’t too bad for short takes; longer takes, however, can be extremely time consuming and therefore a little frustrating.
The good news is that the approach does work: after a rather clumsy experience with the hardware and lack of preview, the experience of using iPi Desktop Motion Capture paid off, yielding some pretty solid full-body mocap.
Small delicate moves and bold aggressive moves were all captured well. Some floor slippage was seen, but nothing that can’t be cleaned up in post in MotionBuilder. However, only BVH, Collada and SMD formats are supported; FBX support would definitely be a welcome addition.
It’s also worth noting, that the iPi desktop mocap system does not currently offer a facial capture solution. So, while the system works well, it isn’t perfect. However, its price certainly makes it an attractive proposition for lone artists and smaller studios for whom the far superior (and polished) marker-based OptiTrack is just a little beyond reach.
With its passionate user groups providing lots of feedback, iPi Soft is one to watch, and iPi Desktop Motion Capture is worth a punt – providing you can happily work around its shortcomings in terms of hardware and lack of live interaction.
It certainly does what it says on the box; it just needs a bit of polish.
• Markerless motion capture
• Moderate PC hardware requirements
• Delivers solid data
• No live preview
• No FBX support
iPi is a clever bit of kit and certainly brings markerless mocap to the masses. A little too low end for premier facilities, it will, however, find its niche market in smaller studios and lone artists
By Craig Crane
Craig oversaw crowd work on Double Negative’s 10,000 BC and 2012, and is currently working as Lidar Supervisor on Captain America and John Carter of Mars
on Wednesday, January 5th, 2011 at 1:10 pm under Applications, Reviews.
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Tags: desktop motion capture, iPi Soft, markerless, mo-cap, motion capture