Position Pass and Camera Metadata Screengrab

The first is the embedding and extraction of a camera transform from the metadata of an EXR.   3ds max (and some other packages) write out the position, rotation, field of view, etc. to the metadata of EXR outputs.  Since we use this file format a lot, it’s a pretty easy thing to use in production, as it doesn’t require a special operation to export the data from the 3D scene.  It’s not as flexible as outputting an FBX, but it can be done without opening (or even finding) the 3D file.  The transform is stored in the metadata as a 4×4 float matrix, and using SimpleExpressions, you can apply the transform to a Fusion 3D Camera per-frame.  If you’ve ever used RPF files with Combustion, you’re probably already familiar with the workflow, we’re just doing that with EXR’s and Fusion now.

The second technique is the rendering of a worldspace intersection pass.  By rendering the location of the surface as an RGB vector, you can find the location, per pixel, of each sample in the render.  Combined with even a hardware rendered “beauty pass”, you can easily place your render into the “world”.  You’re limited to only seeing the first intersections, and only what the camera sees, but in many cases that’s all you need to see.  It’s smaller and faster than an animated FBX sequence, and you can play around with it with image tools.

The fun part is combining these techniques, getting both the shape of your scene and the location of your camera in one quickly rendered EXR sequence.  You can then use this information to try out some various camera separation and convergence setups using the stereoscopic rendering of Fusion, which can range from simple anaglyph to  full quad-buffer shutter setups.  The quality isn’t great, but it’s interactive, and until 3ds max gets better rendering of stereoscopy in the viewports, it’s a fast way to test out camera settings.

The pass and the camera can also be used in the composite as well, for making mattes, placing elements, etc.

(85MB .rar file)

ColorBlind fuse

It’s not a perfect simulation, since it only does a linear color transform, not accounting for local color frequency, and it doesn’t account for any output specific color shifts.  Nothing unusual when it comes to color, of course.  Typical things to consider, colors may look different on an LCD screen compared to web offset printing.

You can use this as a viewer macro, though I may at some point make a proper Cg viewshader.

Download ColorBlind Fuse 1.0

Fuses, however,  let you use handy methods to modify a matrix.  I’ve used some of them to create an RGB equivalent of the 3D Transform tool.  It has a similar UI, just as 3TT does, but this modifies RGB, not XYZ or UVW.

Color Matrix Transform fuse

Why would you want to do this?  Imagine that your RGB isn’t color, but UVW coordinates from a 3D render pass.  Now you can do texture transformations by using this tool to modify the mapping.  Also, if you have comps where you’re converting XYZ to RGB, you can use this to post-edit the tranformation, so you can apply spatial transformations in the form of XYZ -> RGB -> ColorMatrixTransform -> XYZ.

In the future I might add an input and output similar to the Color Matrix tool so you can insert a matrix found elsewhere, as well as generate an output matrix you can read off, but for the time being, input matrices can processed by the Color Matrix tool just prior to the ColorMatrixTranform tool, just remember to use 32bit float colors.

If you’re a bit confused as to what the tool is doing, try viewing the results in the 3D Histogram SubV.   Really helps you get your bearings.

Color to Mono

Mono to Color

Why would you use this?  Memory savings, mostly.  An alpha-only image takes 1/4 the RAM of an RGBA image.   For scalar data operations, or masks, or any time where you don’t need vectors, you can store more data in cache and thus make everything fast and smooth.

The latest builds of Fusion also support mono-channel textures in 3D, so in cases where your video card doesn’t have a lot of memory, this can be even more useful.

Why not just use a Bmp to convert to mono?  Well, it’s a different class output, so it keeps trying to connect to mask inputs.  And you can’t set a Bmp to passthrough and get color data out.  You get nothing.  Furthermore, having Bmp’s littered around your flow is ugly.

Converting from mono back to color could be done by masking off a BG set to white, right?  But you’d have to keep making that BG be the same size, depth, etc as your incoming mask, and that’s not convenient.  And it uglies up your flow, too.

Download ColorToMono 1.0

Download MonoToColor 1.0

As time permits, I’ll go through my other fuses and add similar functionality.

Absolute Value

I’m often trying to find the magnitude of something, regardless of sign.  Commonly done for things like normals or velocity or distance.  You would expect there to be a built in tool for that sort of thing, but there isn’t.

Previously,  I did it with a CT or a Fuse operating on a per-pixel basis.  An f.Color.rgb = abs(f.Color.rgb) sort of thing, which is pretty slow in Fusion as a CT or Fuse, but is plenty fast in Cg.  More on that later.

Today I had an idea on how to do it with a matrix.   The basic idea is to scale the the image by .5, and by -.5 and find the difference of the two.  So |x| = (.5*x)-(-.5*x)

This method is much faster.  The resulting Fuse runs about 40% faster than a CT, and several times faster than the old Fuse I had made which operated pixel by pixel.  Unfortunately, ROI isn’t supported yet for Fuses, so if you have a tiny ROI, the CT or the CMx’s will both run faster.   EDIT: ROIDS can be supported in Fuses…  I’ll need to add it to the Fuses I’ve posted so far.  Stay tuned…

So here’s the Fuse, a Cg ViewShader that lets you view the absolute value in a Viewer, and an example comp showing the CT, Fuse, and CMx methods, as well as the ViewShader.

Download FAbsolute Fuse 1.05

Download Absolute Value Viewshader 1.01

Download Example Comp (Absolute Fuse) A01

It would be interesting to see if the disparity between the speeds  of processing the matrix vs per-pixel goes away when you compile a c++ plugin…

Cropped compare of anisotropic proxy of a 4k plate

Along those lines, we’ve taken to using an inline proxy setup that provides some benefits over the built-in proxy.  It’s based around the assumption that tools take into account the pixel aspect ratios, which differs from the code branching that occurs with proxy, so you may not get correct results, but it’s also shows when tools are improperly handling pixel aspect ratios.

The general idea is that you scale the input by some factor, then divide the pixel aspect by that same amount.  Fusion handles the transformations just fine, knowing that an image that is 2048 wide, but with pixels that are .1 units in size is the same size as an image 20 pixels wide with pixels 10.24 units wide.

The image above shows a 4k plate proxied down to 12/24, meaning it is proxied in X by 12 (a value not available in the built in proxy) and the Y by 24 (the built in proxy does not allow anisotropy).  The filtering is done using the Catmull-Rom filter (filter options are not available to the built in proxy).

These advantages are minor, however, compared to the ability to:

1. Animate the proxy scale
2. Apply it to only select portions of your comp (or set it to be a different scale in different parts of your comp)
3. Preserve the cache of the input tools

I’ve attached a comp to demonstrate this.

(Hint:  Ctrl+1 resets the view scale/offset for A|B compares)

The end is near...

I’m on my way home now.  Ben and I got to see a lot of really nice presentations, and we had some good discussions with researchers and suppliers.

Texmoca

Texmoca is a very unique demonstration of natural occurrences of Voroni type packing.  Small heating elements burn oil which spreads out, cools, and falls in beautiful convection currents.  Best coffee table of the show, but the heat it gives off makes it bad for drinks, good for fondue.

Ground Substance, from LabStudio

The Generative Fabrication exhibit was really nice.  Particularly the contributions by LabStudio.

Field3D

Sony Pictures Image works is working on an open source voxel storage format, Field3D.  You can check out the project or the programmer’s guide.

GPU Illumination

Went to the course titled Advanced Illumination Techniques for GPU Volume Raycasting, fortunately it wasn’t a rehash of the 2006 book, but had mostly new work, including some really nice ambient occlusion, scattering, and shadowing techniques.  Also showed some of Voreen.  Really nice bunch of guys.

Ok, I’m off to see a panel discussion with Jenny Sabin of LabStudio.

Gel Sight

Gel Sight is a retrographic surface imaging technique that was wonderfully elegant in it’s simplicity and effectiveness.  They also gave out free samples…

Cuda raycasting 13GB of cryomacrotome goodness (in stereo)

Nvidia had a stereographic interactive realtime rendering of the full 13GB Visible Human dataset being rendered in CUDA on 3 Quadroplexi.  Very impressive.  The glasses used were the new Nvidia active shutter glasses, and were very effective.

Resistive multitouch in many form factors

A new startup out of NYU showed a novel resistive multitouch device.  Very effective, low cost, and suitable to many applications.

VLC madness courtesy 2 Fusion-io cards

Fusion-io showed their new “budget” nonvolatile storage adapter, the ioXtreme.   $900 gets you 80GB, with a read speed o 700MB/s.  The IO’s aren’t very high, much less their enterprise solutions, but that doesn’t matter if you are reading sequential data.  The booth was pretty crazy, too, one of the better live hardware demos I’ve seen in a while.  I’ll get some pictures tomorrow.  VLC never looked so impressive…