TORONTO — SideFX (http://sidefx.com) has released Procedural Dependency Graph (PDG) technology, which will be available in the upcoming release of Houdini 17.5 as a new Houdini operating context called TOPs (Task Operators) and as a standalone application called PilotPDG.
PDG is designed to describe complex dependencies visually with nodes as well as transform that dependency description into a set of actionable, monitorable tasks. It can also distribute those tasks with the help of a scheduler and compute them in parallel.
To illustrate the challenge when dealing with dependencies, consider the example of a procedurally-generated city - with a variety of complex buildings, roads and sidewalks, traffic signs, etc. If the technical artist were to make a structural change to the city, the geometry needs to be rebuilt in a sequence of steps - first, build the roads, then create the city blocks, then construct the buildings, followed by windows and interiors, etc. All of these things need to happen in the correct order, to happen as quickly as possible and to leverage all available compute resources with maximum efficiency.
“PDG tackles this problem by generalizing the idea of a dependency graph,” explains Ken Xu, senior software architect at SideFX. “Dependency graphs are used all over the industry, but come with an inherent assumption - that nodes in the graph only execute once. PDG creates a highly flexible template graph where many instances of the node are allowed to execute simultaneously. This generalization allows tasks to be parallelized, complex dependencies to be described, and higher level reasoning to be performed where we can now describe what is to happen for processing in general, rather than a specific instance of a problem.”
The richness of the stock nodes of the PDG platform allows users to benefit from visual programming, with huge gains in efficiency by allowing tech artists to avoid writing code to achieve many of the typical workflows. This helps democratize the pipeline ecosystem, giving artists the power of automation while programmers can take advantage of PDG to efficiently distribute pipeline tasks to a compute farm.
The first adopters of the alpha and beta versions of PDG have been pipeline managers at film and game studios, who have found significant workflow efficiencies using this new technology. While PDG will be available in Houdini 17.5 onwards, and can be used to manage Houdini workflows, the power of PDG extends to the wider pipeline to other commonly used applications, such as Autodesk Maya, Adobe Photoshop, FFMPEG, Thinkbox Software Deadline, and others. Integrations can be developed either by the community, or by software developers such as Adobe.
“We’re excited to work with SideFX on the integration with Adobe Creative Cloud products,” says Pam Clark, senior director, product management for Photoshop. “It was straightforward for us to develop a PDG node which could interact with Photoshop’s actions, and we’re looking forward to seeing how creative artists will make use of Photoshop in the PDG ecosystem. Moreover, we see this as just the beginning of a series of upcoming integrations with other Adobe apps like Dimension and our newly-acquired Substance suite of materials tools.”