The hourglass shattering effect required a lot of exploration in Houdini DOP’s. The sidefx glass of water shattering tutorial (I hesitate to call it a tutorial) as well as the example files for the voronoi fracture OTL were helpful in giving me a starting point to build my effect.

WORKFLOW

After a month of R&D I had the following workflow figured out:

I used the voronoi fracture OTL to create a dynamic fracture simulation where the hourglass drops and is fractured automatically (and fractured even more when the glass collides with geometry). I then took the fractured glass geometry and used it as a collision object for a particlefluid sand simulation.

The fracturing geometry, however, created a problem for the particlefluid solver for the sand. Because the glass geometry was being fractured dynamically (even though it was cached out in a bgeo sequence) the point counts would change and the particlefluid solver would freak out. This seems to be a common issue with the dynamic fracture tool, as people from SideFX effectivly said “yeah, we know, sorry”. It seemed like I would have to pre-fracture the geometry.

I really liked the look that the dynamic fracture gave so I was hell bent on finding a way to use it. Getting it to work required some ugly trickery. I first identified all of the frames in which the voronoi sop had performed a new shatter. Thankfully, there were only four or five. Then, I divided up my cached bgeo sequence into different sets of frames respective of the fracture points. I had a sequence that went from 1 to frame 316, for example. On frame 317, the geometry fractured for the first time, and so that bgeo set went from 317-358, when another fracture took place. For this and each subsequent set of frames, I duplicated the first frame in the set for how ever many frames were missing, starting at 1. So if the set went from 317-358, I took frame 317 and duplicated it so that single bgeo file was used for frames 1-316 in that set. This way I had a set that went from 1-358, but with frame 317 as the ’starting’ point.

By doing this, I ended up with a series of bgeo sequences that was consistently the same point count and never fractured beyond its initial configuration. It is now possible to take these sets of geometry into the particle fluid simulation and ‘trick’ Houdini into accepting it.

Unfortunately, it wasn’t enough to just use a switch DOP (which I found to be incredibly buggy to begin with) on the glass geometry, as the particlefluid solver would still freak out. To get this to work, I had to actually write out the particlefluid sequence to one of my pre-determined fracture frames, say 1-316, and then re-import the last particlefluid cache frame as a particlefield and set the particlefluidobject to use the that field as its initial state on a new simulation with the next set of fractured collision geometry. So, instead of performing one simulation for the sand, I had to perform a simulation for

every set of fractured geometry, using the last frame sim’d as a starting point for the particle fluid.

To recap:
1) DOP simulation of glass shatter using voronoi fracture OTL written to a bgeo sequence
2) Separate out the sequence into sets respective to frames where fracturing takes place
3) Duplicate first frame of each set so the set starts at 1 (instead of 317, for example).
4) Simulate particlefluid using the different sets. Stop the simulation the frame before a fracture occurs, re-import the last frame you simulated, use it as an initial state with the next set of collision geometry.

You’d think that it would be possible to do this without separating out the fractured collision geometry (if you just stopped the simulation before a fracture occurred in the collision geometry and set an initial state from the last frame) but I found it to be necessary in order for Houdini not to crash. Perhaps someone else can get that working.

FRACTURING THE GLASS

The DOP simulation used for the voronoi fracture is based on one of their example files, stripped down a little and simplified. Seperate RBD objects are brought in, one for the glass (which is run through the jl_fracturedpieces) and two others for the wood and metal connector of the houglass.
The simulation generally performed as expected. I found that fractured pieces created by the voronoi fracture tool weren’t getting much gravity applied to them respective of the original geometry, so I created an additional gravity field that only affected objects named rbdobject1_piece*. This allowed a fine degree of control over the look and scale of the simulation, eg how much the pieces would float out before being brought down by gravity (useful for making everything look larger). Setting the various densities on the RBD objects also gave it a more realistic interaction, eg glass was 25 and the wood was 2000.

Additionally, I found that the glass pieces were passing through the portions of the wood structure that were thinner, such as the dowel rods in the mid section of the structure. I found that increasing the Ray Intersect Divisions on the RBD object for the wood structure to 90 90 90 solved this problem (turning on Show Collision Geo is useful here).

FLUID SIM

The initial sand geometry was created by subdividing a box. The actual amount of particles wasn’t determined by the subdividion level, it was determined by a parameter called “particle separation”, but I found having a liberal subdivision level was useful for starting out. At this point I also brought in all of my separated bgeo sequences via file sops.
The simulation itself is based on the shattering glass example from Sidefx. It’s actually fairly simple once you figure out how to work with the collision geometry. In the screenshot to the left, you can see by which set of collision geometry I have connected that I’m starting at frame 362. The particlefluidobject would be set to start at frame 362 using 361 of the particlefluid simulation as an initial state.
To write out the fluid sim, I used a DopImport with an object mask of: `dopobjscreatedby(“/obj/FluidSim/particlefluidobject1″)` set to “Fetch Geometry from Dop Network”.

BRINGING EVERYTHING TOGETHER

When bringing back in the hourglass geometry simulation, I applied the materials using group nodes I had created prior to the dynamic fracture simulation. For some reason, I had to lay down a transform sop at the end of the tree for the materials to show up correctly.

Bringing in the cached particlefluid sequence is a little more involved. I decided to go with metaballs for the sand, and ended up having to set the metaball radius fairly low (0.8) in order to get something that wasn’t incredibly clumpy (it was still clumpy, ultimately another method is probably better).

Applying metaballs to particles is fairly simple and involves only a copy node at the core. I found that I had a lot of excess particles that streamed out everywhere (out of the field of view) that were basically lower than the threshold of the metaball, so they were effectively invisible. However, it took an incredibly long time to calculate the metaball to poly conversion with all of these excess particles. Using a group node to group together particles within the area of a sphere and then deleting the excess particles saved me days of simulation time. This can all be done within the group node and then appending a delete node that deletes the group’s inverted selection.

Once I had written out polygons from the metaballs, I applied the sand material (a simple UV projection) and faceted the polygons.

GLASS REFRACTION AND CAMERA PROJECTION

I spent a lot of time trying to figure out how to pass an alpha through the VEX glass material. Basically, I realized it couldn’t be done by the nature of refraction. Once I accepted that I would have to lock in the position and animation of the hourglass in Houdini rather than in compositing, I went about figuring out how to get the background refracting through the glass.

Simply applying a viewport or camera background doesn’t affect refractions. A relatively simple method is to take a grid object, position it roughly so that it covers the entire field of view for the course of the shot, and then project UV’s from the camera onto the plane. This is done via a UVTexture node set to “Perspective from Camera” and pointed to the respective camera. You can then apply a material that has the image sequence as the color.

Good settings to use for materials that need to be self illuminating, such as the image sequence background, are (in a VEX Supermaterial) a diffuse of 4 and a transmit of 1. Everything else should be zero. The image sequence is applied in the diffuse channel. Of course, the alpha for the grid should be turned on or off depending on the needs of the shot. If it’s set to Phantom renderable than it will still refract through the glass but won’t show up outside of the glass.

Continued after the jump:

But it seems all good things must end. Last year, D&K released their first album since 2002’s masterfully jazzy Gran Reserva. As I mentioned before, I bought “Music Matters” without hesitation. Even while keeping my expectations in check, after the initial glee of having a new album to play wore off, I realized they had released a collection of meaningless pop dribble. Not only had they completely abandoned their jazzy electro roots, they indulged in a lot of what’s worse about modern pop. I’m a drummer, but even I can identify cheesy and cliche chord progressions and rhythmic structures.

The lyrics are even worse. Before, if they had vocals at all, they were carefully cast singers or sampled sound bites from vintage sources, mysterious out of context, which added quite a bit to the depth of the songs. In 2002, Madita sang on Gran Reserva with her lost-in-translation word structures that left the deciphering and meaning up to the listener. However, on “Music Matters”, a cast of bland vocalists recite lyrics so egregiously shallow they begin to hurt your ears. “It’s over, tell me why’d you even bother to call. It’s over, and I need to get away from it all.” Kill me now.

There are two or three tracks that are stronger. Most notably “Worm” which sounds like it could have been co-written by Madita (maybe it was). “Dolby” is one of the few songs that slightly carries through their legacy sound with it’s driving, chopped base line and evocative layering.

In the end, you have to consider why such a brazen title as “Music Matters” was assigned to a collection of work that is so incredibly devoid of meaning.

None of this would really matter if it didn’t hint at a larger problem. Just two weeks ago, Madita released her third album. “Pacemaker” takes all of the glam 80’s electro elements from “Too” and mixes it with the bland pop of “Music Matters”. It’s pretty clear she’s taking cues from bands that play on the speakers of gag-inducing glitz clothing stores one would find in every mall (the store Forever 21 comes to mind). The song “Runaway” is a replication of the band Cut Copy’s signature style, complete with a distinctive splashes of 80’s rhythm guitar that Cut Copy effectively incorporated into their album “In Ghost Colors”.

But where Cut Copy and M83 succeeded, Madita falls flat. The songs are not evocative. After the first listen, you’ve heard it all. Even the lyrics are no longer interesting, her distinctive structure is gone; either she’s gotten really fluent in English, or she’s suffering dZihan & Kamien’s mutual “let’s appeal to the lowest common denominator and make a quick buck” creative block.

This regression from evokative to bland is troubling. It’s a shame. If I ever was a fanboy for any artist, it was Madita. I still love her first two albums, and dZihan & Kamien’s earlier works will forever be engrained in my conscious. I won’t be pre-ordering any future releases from them, however. I can only hope that their new populist sound brings them greater financial success so they can return to their creative roots.

Dream Sequence

A two minute breakdown of shots created by Stephen Withers for the film “Speak and May the Plague Take You” dir. by Cody Duckworth. Creating the surreal falling clocks and hourglass vfx required extensive dynamics work in Houdini as well as a large amount of roto and comping.

Practical elements, including water and falling leaves/debris, were shot with the help of David Kendall. Michael Rogers helped out with some of the 3D modeling.

Speak and May the Plague Take You – Directed by Cody Duckworth, Visual Effects Supervisor Stephen Withers.

Practical Elements

Some words:

The highlight of this project was creating the surreal imagery of the falling timepieces during the dream sequence. The hourglass and sand were a very complicated Houdini simulation, while the other clocks were rendered out of Maya or were 2d cards. The roto work was pretty time-consuming as no greenscreen was used and there were multiple characters running in a single shot.

While many of the shots required not-so-subtle effects, Poseidon emerging from the water took the cake. I thought lots of splashes and water spray would be cooler than simply showing some bubbling (and ironically, easier to pull off). We shot some water elements in the back yard using some cups, a bucket and a hose. The water was back-lit so it showed up nicely against black. I comp’d it with background plates of the ocean. While there are some scale issues (I could only shoot the elements at 60fps) I think the shot serves its purpose!

3D Track

Another roto-heavy shot required the addition of the looming shadow of Poseidon dwarfing the main character. Since Poseidon would theoretically block out the sun, this necessitated the removal of the shadow cast by the dwarfed main character. To accomplish this, I tracked the original footage and was able to generate a clean plate in 3d, having cloned out his shadow. This clean plate was composited with the original and an overlay of Poseidon to create the final effect.

Reflection Replacement

There were a few spots where I had to clean up the original footage. I did pretty involved stabilization in After Effects for four or five shots, and in one case had to generate completely new reflections in one of the character’s glasses. These science-goggles were almost perfect mirrors, which made the task interesting. I was able to create a fake reflection in Photoshop having sourced from some photos of the set I snapped. I then tracked it in and did my best to give the reflection the feel of the original.

“Speak and May the Plague Take You” was certainly an interesting project, different than the usual fair. It presented a lot of unique problems to solve and as a result I have some work that stands out a great deal from, well, the rest of my work.

I’d like to give shout-outs to Michael Rogers, who did some additional modeling, as well as David Kendall, who let me borrow his camera and helped shoot the practical elements (and got a little wet). Also, I’d like to thank Oliver Palmer and Ryan Bowden from SideFX for their Houdini expertise.

Film

Digital

On The Magic of Film, Alex shot with his 16mm camera on black and white reversal, in addition to shooting on the Canon 5D Mk II. The film wasn’t developed in time for the bumper contest, but it came in recently and I decided to put together a cut using only the film footage.

The differences are pretty clear. This particular 16mm stock isn’t really supposed to be scanned at 1920×1080, so it’s a little soft, but it still holds up fairly well. The flashes of light from (what I assume are) exposure artifacts and spill, when they don’t ruin a shot, are quite charming.

Digital

Film

Some of the film takes weren’t usable, and there was no way of knowing on set if the take worked – but on the 5D, because I was able to review the shots instantly, I found that I got more of what I needed. The film cut had to be fudged a bit in editing, and doesn’t work as well as the digital cut. The film cut does, however, feel more visually unified.

Watch the 16mm Cut

Unfortunately, in addition to not coming in on time, the lab that scanned the film telecine’d the output file, creating interlacing and pulldowns and a whole bunch of other garbage. They probably thought it was shot at 24fps, because telecine is a process used to convert 24fps to 30fps for television viewing. They told me to reverse-telecine the file, which would have removed a pulldown, except for the fact that the film was shot at 30fps to begin with, not 24, so now it’s completely mucked, plus the interlacing problems. It would really have been easier to just have gotten progressive tiff files for each frame, then I could have played it back at whatever speed I wanted without dealing with pulldowns. That’s just a whole lot of unnecessary steps. In the movie below, the interpolated frames are visible especially in the motion blur. I ran a deinterlacing process, the artifacts of which are visible on some of the edges. I may try to correct the whole thing eventually, but don’t have the time now.

In any case, the whole processes was quite an experience. It was really exciting to have my production shot on an older film camera side-by-side with the Canon 5D Mk II, very much the bleeding edge in digital video. What the original digital cut here! Don’t forget to VOTE for the bumper!

Color Corrected

Original

Having just completed The Magic of Film bumper, here are some color correction comparisons. The footage had all been converted from the native h264 to ProRes 4:2:2 for easier editing, however, both compression methods started to break down the farther I pushed the colors; this is where RAW video would *really* be nice. The algorithms also broke down in shots that had a lot of movement and motion blur. Overall, however, the compression is passable, especially for web distribution, and the other benefits of using the 5D certainly outweigh the mediocre compression quality coming off of the camera.

Original

Color Corrected

As for the color itself, I wanted to go for a look for the footage that wouldn’t jar the audience during the transition to and from the black and white shots. I went for a warm duotone sort of desaturated look, bringing down the levels on the backgrounds so the subjects would pop a little bit more.

Footage from the Camera

Continuing with the coverage of the 5D shoot, here’s a greenscreen element we shot a few days ago. The setup was ghetto; a portable screen, filled with wrinkles,  in the living room. On any other camera, the wrinkles would have caused problems down the line in compositing, but because we were able to put a 70-200mm lens on the camera, the screen was thrown completely out of focus. That’s not possible to do with prosumer camcorders without a multitude of adapters and accessories, you’d essentially have to put a better lens on the camera somehow. In all of the footage we’ve shot, the huge size of the sensor on the 5D compared to prosumer camcorders really shows in the visual look of the image and the amount of depth of field that is obtainable (take a look at some of the shots in the post below).

Matte

Because the screen was thrown out of focus, it was much easier to pull a clean key. The process was also much simpler; there wasn’t a need to pre-blur the green or blue channels to compensate for a 4:2:0 colorspace or other foolishness that accompanies prosumer formats.

I’ve been raving about it quite a bit, but working with this camera is such a breath of fresh air to someone who’s had to work through the godawful limitations of prosumer formats in a demanding visual effects context.

After shooting on the 5D, and having just attended a lecture by DSLR video extraordinaire Vincent Laforet, I’m incredibly excited about using this camera again in the future. Because of the nature of this particular production, we also shot with a 16mm film camera my DP owns – I can’t wait to get the film back to compare the two cameras.