Linden Lab has recently acquired the right to sub-licence the Havok physics engine technology used within their Viewer. This has resulted in the Lab issuing new guidelines to third-party Viewer developers wishing to incorporate advanced Viewer capabilities developed using the Havok technology within their offerings.

The guidelines read in part:

The technology is provided in the form of an autobuild package ‘llphysicsextensions’ containing header files and the required library. This does not directly expose the Havok APIs, but a set of higher level interfaces specific to the viewer. Sources for the wrapper itself will not be open source. The llphysicsextensions package includes all features that use Havok (currently convex decomposition and features related to navigation mesh for pathfinding).

This move is already a subject of debate among TPV developers and the OpenSim community, because the sub-licence associated with the guidelines appears to place clear restrictions on TPV developers, notably in clause (b) of the Conditions to Grant, which reads:

(b) Sublicensee must require the Third Party Viewer to connect only to servers owned or operated by the Company; [i.e. Linden Lab]

So if a TPV developer wishes to work on both Second Life and OpenSim, they’ll have to look at options very carefully, as Maria Korolov points out in Hypergrid Business.

Within Second Life, there is concern as to what this may mean for some TPVs – specifically those utilising GPL rather than LGPL. Such Viewers appear to be effectively excluded from applying for a sub-licence. While this will not prevent such Viewers from accessing Second Life, it does mean that they’ll be excluded from using code that implements the Havok capabilities. The requirement for TPVs wishing to obtain a sub-licence being required to be publicly listed on the Third-Party Viewer Directory may also have a negative impact in some quarters.

The flip side to this, however, is that it means Havok physics will effectively be in the Viewer itself, which could pave the way to many new enhancements and capabilities within Second Life. As such, it is far to say that the move to sub-licence the Havok engine is less about LL attempting to restrict Viewer development per se (the apparent attempt to push out V1-based Viewers not withstanding), but rather to provide a means by which they can integrated what is effectively a closed-source, licenced product (Havok) into what is essentially an open-source project (the Viewer) without breaking the terms of their agreement with Havok.

The program itself is not available as yet, and discussions within the community are ongoing, with TPV developers aiming to seek further clarification from Linden Lab on possible impacts on their work – again, specifically where OpenSim support is concerned.

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