Blender 2.75 delivers a boatload of cool features and bug fixes
Cool new features coming to Blender 2.75
The release of Blender 2.75 is right around the corner. Granted, with a two[-ish]-month release cycle, that always seems to be the case. Of course, this particular release cycle has happened squarely in the middle of the Blender Institute's production of Cosmos Laundromat, also known as the Gooseberry Open Movie Project. A lot of the goodies from that project are still in heavy development (and use) in a separate branch; however, there have been a boatload of cool and interesting features—in addition to critical bug fixes—that have found their way into the master branch. Let's have a gander at some of the big ones.
One of the biggest features merged into Blender this go-round were from the multiview branch. In short, Blender now fully supports the ability to create stereoscopic 3D images. With the increased pervasiveness of 3D films and televisions—not to mention VR headsets in gaming—a lot of people are interested in generating images that play nice in this format. And now Blender can.
It's pretty cool stuff. There's support for everything from the (admittedly chintzy) red/cyan anaglyph 3D display, to more advanced interlacing and page flip display techniques. The support for this kind of display isn't just in final rendering, either; it's also available in the 3D View. So if you happen to have a 3D display device as part of your computing rig, you can actually work in Blender, in 3D.
There's a great write-up on actually using Blender's stereo 3D features in the Blender reference manual. (Hooray for documentation!)
Better AMD GPU support in Cycles
Blender's GPU-accelerated renderer, Cycles, got a huge bump in this release as well. Although Cycles is designed to take advantage of the computational power of modern GPUs, up to this point that capability has been crippled on AMD-based video cards. Well, happily, a few AMD developers submitted a massive patch to Blender that effectively allows Cycles to render using AMD GPUs.
Not all of Cycles features are supported yet—including motion blur, camera blur, subsurface scattering, volumetrics, and transparent shadows—but those will come in time. We had to wait for those features to get supported on CUDA GPUs when they were first introduced, too. The biggest thing is that if you have a video card that's capable of supporting OpenCL for GPU computation, you can take advantage of a much faster rendering experience with Cycles.
Light portals in Cycles
A long-standing gripe from people who use Cycles to render scenes of building interiors is that it would take a very long time for the image to converge on a noiseless result. To help remedy this, a Portal option was added to area lamps. In a given scene, you put an area lamp in front of an opening that light is supposed to come through (window, open doorway, skylight, etc.) and enable the Portal option. At this point, the area lamp no longer emits light. Instead, it serves as a guide to let the Cycles renderer know that this is where the environmental lighting for the scene is coming from.
Sample-for-sample, if you use light portals in your scene, the rendering process is slower; however, because the image converges on a more noise-free result with fewer samples, the overall render time should be dramatically reduced. There are an impressive set of tests and experiments in a thread at blenderartists.org. (Full disclosure: I'm a moderator on those forums.) Now your characters don't have to be outdoors so much.
One of the features that Blender users have been wanting for ages is the ability to make modifications to multiple selected objects at the same time. For example, if you have a dozen objects with a Subdivision Surface modifier and you want to increase number of subdivisions they have, it used to be that you would have to select each object individually and change those values one at a time (or write a little Python script to do that for you). Now you don't have to go through that hassle. You just select your objects, hold the Alt key while changing your subdivision values, and all of them change.
Granted, this feature could still use a bit of maturing. Although it works on all number entry fields, sliders, check boxes, and drop-downs, it doesn't work for anything that's operator-based. For instance, if you want to add the same modifier to all selected objects, that's not yet possible. Also, the decision to use the Alt key modifier is temporary, and a more natural approach is likely in future release of Blender. But, that said, this little feature is a huge benefit to people who work with a lot of objects in a scene.
A quiet addition on this release is a massive overhaul of Blender's dependency graph. This is a big deal when it comes to rigging and animation in Blender. Development (and plans for development) of this feature have been in the works for a long time—to the point that it's reached near-mythical status. There's a great write-up on the dependency graph and what it's for on the Blender Code blog, but here's the short version: Any time you set up a relationship (parenting, constraints, drivers, etc.) between objects, that's considered a dependency. When you make a change to one object, the dependency graph is used to determine which objects are affected by that change, and then update them.
When Blender got the ability to "animate everything" in the 2.5 updates a couple years ago, the existing dependency graph handled it adequately, but was slow, would fail in some cases, and would report cyclic dependencies where you didn't think there were any. The ultimate effect of this was that "animate everything" became "animate mostly everything". With the updates to the dependency graph in 2.75, some big steps have been taking to get that "mostly" out of there (and speed up things a bit, too).
Of course, because this feature touches nearly every corner of Blender, its full migration as a replacement for the old dependency graph is being done in small, controlled steps. So in 2.75, the legacy dependency graph and the new dependency graph live side-by-side. If you want to try out the new one, launch Blender with the --enable-new-depsgraph command-line argument.
A fun addition to this release of Blender is the inclusion of support for symmetrical painting in the 3D View. Doing symmetrical sculpting in Blender, where modifying a mesh on one side automatically updates the mesh on the opposite side, has been possible for a long time; however, up to now, that capability hadn't extended to painting. A really good preview video walks through this feature:
It's definitely a great speed-up for getting detailed textures on your models.
Go test it!
These aren't the only enhancements to Blender in the 2.75 release. You can get a full picture of them in the release notes on the developer wiki. As of this writing, there's a release candidate that's out and available for testing. If you're a Blender user— even an occasional/casual one—go download it and take it for a spin. If you find an issue or a bug, report it. Developers can't fix bugs that they don't know exist.
And if you happen to be reading this after the official 2.75 release: Have fun with the new features! (But you can still report bugs, too.)