July 18 2009
This lens shader offers an extremely simply way of rendering passes including normals, UVs, Object ID and Material ID pass.
Sometimes you just want to render out a specific pass without re-rendering the entire scene or fiddling with a complicated shading network.
minLensPass renders out lots of extra information about your scene that may be useful for compositing purposes, including normals, UVs, Object ID, Material ID, depth, position, CPU time and alpha.
Many of these passes are particularly useful when used in combination with my After Effects plug-in Normality. Or, in the case of visualizing CPU time, they can help you optimize your scene.
Usage
minLensPass is simply applied to your camera’s lens slot. Select your pass and hit render! The shader requires no further setup — it just works.
June 22 2009
The Object ID Selector for After Effects that I announced earlier has seen several improvements in the latest update and is nearly ready for production.
The main improvement in this version is that the plug-in is no longer just a dumb keyer that lets you pick objects by their color. Instead you may opt to pick objects by their position!
This makes for a super-efficient workflow: Simply click on an object in your beauty pass and the plug-in will automatically isolate it for you — no need to switch to the Object ID pass, select a color area, switch back to the beauty and pray that you chose the right object.
It really couldn’t be easier!
If all goes well we’ll be using this plug-in in our upcoming projects.
June 20 2009
Adobe After Effects is shipped with a number of extremely capable color keying plug-ins. To interact with my latest 3D shader minObjectID I required a simple chroma keyer that would make it quick and simple to select individual objects by their associated color ID for further processing as an alpha mask.
The ideal candiate should fulfill these basic requirements and not much more:
- Be as simple and efficient as possible
- Output a specific color and not whatever object was keyed
- The result should be invertible
- Be extremely precise with no room for tolerance
- Works in 8-, 16– and 32-bit color space
None of the included keyers met all of my criteria because they either didn’t work in floating-point mode or were simply overkill for my purposes.
I then remembered that I had once started to write a little chroma keying application a few years ago and so I decided to sift through my old backup drives in the hopes of finding this lost piece of code in order to rip out its guts and to form it into the ultimate Object ID selector for After Effects.
Fortunately, I ended up finding the project and here I am to write about my new plug-in, simply named Object ID Selector for now.
This plug-in has very few parameters, making it simple to setup. It’s in no way an all-purpose keying solution, but for selecting IDs of objects I think this stripped down keyer is the ideal choice.
I have not yet considered solutions for the aliasing issues that might arise between overlapping objects but I hope to find a practical answer to at least mitigate the problem.
Once the plug-in has gone through a phase of testing I will probably make the software publicly available so it can be used in combination with minObjectID.
June 19 2009
My latest shader assigns each object in a scene a distinct, randomly selected color, the so called Object ID. I have decided to offer this shader as a free download to the mental ray community.
An Object ID pass isn’t exactly pretty, but it is incredibly useful because a compositing artist can apply effects or corrections to individual objects or specific areas without the need to render separate masks or even paint masks by hand.
My approach to this shader is somewhat naïve in that it randomly assigns a color to each object without regard for adjacent object’s colors or possible repetitions. However, the chances of the same color being picked twice by the algorithm are so small as to be negligible for all intents and purposes.
Download
Download
minObjectID is a free shader for mental ray (Windows x86/x64 and Mac OS X)
Usage
Once minObjectID is assigned to your objects just hit render and you’ll have a random color on each and every object — no need to manually specify object– or label IDs.
Note that this shader’s output is not compatible with Nuke’s or Fusion’s ObjectID format as it does not save to an integer buffer in OpenEXR files.
