What you can do in Bifrost 2.1


Behind the latest release and the latest features.

Previously at befores & afters, we followed the journey of Autodesk’s Bifrost from its earliest beginnings into the visual programming language it is today.

Now, Autodesk has released Bifrost 2.1 for Maya and added a bunch of new features. Notably, these include geometric queries, which allow artists to build compounds using rapid point-cloud lookups, nearest-neighbor searches, and raycasting.

With Autodesk’s Jonah Friedman, product owner for Bifrost, we find out more about what geometric queries are and what they mean for users of the toolset, and what other features are now available.

How geometric queries are part of this release

Bifrost 2.1 adds new nodes and compounds into Bifrost that let you query the closest point or location, points within a radius, or intersections along a ray (raycasting). There’s also a new ‘scope’ node for visualizing geometric queries by drawing their results. But first, what exactly are geometric queries?

In this visualizing of raycasting example in Bifrost, every vertex of this sphere is firing out a ray from along its normal.

“They are basically queries about the world,” outlines Friedman, noting they are now key parts of the graph programming available in Bifrost. “For example, you might have some point in space and you want to know what geometry is close to it. You have some fish, say, and you want them to swim around some rocks, ie. for a collision deformer. So you need to be able to ask, what rocks are near this fish? What rocks can these fish see?”

Other examples of where geometric queries in Bifrost could used include in working out the thickness of CG objects to aid in giving them the right sub-surface look, or for times when you need to scatter points. “I might want the points to be not overlapping each other because they need to be trees or something similar,” says Friedman. “I need them a certain distance apart. So I need to be able to measure how far they are from their neighbors, which means I need to be able to find the neighbors. You can do this with geometric queries.”

This screenshot demonstrates a query of closest points.

Previously, Bifrost had limited geometric query functions – you could find closest points, but not be able to raycast, for instance. Friedman adds that, in general, Bifrost is “so open-ended as a programming language that so much is now possible. Our geometry queries are optimized for speed, meaning that you can use them to do large numbers of searches through heavy geometry very quickly. Speed is often the limiting factor in how large or detailed your effect can be. These queries all work by first building an ‘acceleration structure’, which allows large numbers of samplers to be taken very efficiently.”

“Advanced users who require it can build the acceleration structure once, and then sample it many times. The ray-tracing example above is one example, we trace one batch of rays, and then trace some more based on where those hit, reflect and refract. Building the acceleration structure only once makes these queries much more flexible, especially combined with the open-ended nature of the graph.”

What else is new in Bifrost 2.1

Several other improvements to the toolset have also been made. Alembic IO nodes now support reading and writing multiple meshes with a single file, keeping UV and painted attributes intact. “Alembics can contain multiple meshes and multiple curves and multiple point clouds,” details Friedman. “Now we can read in a lot more of that data and we can bring in whole assets.”

Graph readability improvements in Bifrost 2.1.

There are general performance improvements, too. “We fixed some overheads that result in many graphs running much faster,” says Freidman. “The graph is capable of implementing all sorts of geometry algorithms, where users can manipulate the raw data. In many geometry types like meshes you’ll do a lot of following indices into arrays of data. This is where we’ve fixed some significant overheads, and we same performance improvements in some graphs of 10x.”

The pre-built missile hit graph.

A final extra addition includes new pre-built FX graphs, such as vehicle exhaust, fast aero and missile hit. “The idea here,” explains Friedman, “is that you can just double click on one of these and it’ll create the graph in your scene. Then you’ve got a starting example of this pre-made, high quality effect that’s all ready to try out and render.”

You can find out more about the latest Bifrost 2.1 release here.

Sponsored by Autodesk:
This is a sponsored article and part of the befores & afters VFX Insight series. If you’d like to promote your VFX/animation/CG tech or service, you can find out more about the VFX Insight series right here.

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