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Kicking Toasters, Old-School

[url=http://web.mac.com/david_of_mac/iWeb/3D%20Website/Battlestar%20Galactica_files/Bombardment.jpg]So, here we have my next step in the wide world of explosions, from the explosion-and-smoke-filled universe of the new Battlestar Galactica.[/url] All of the effects were done in-camera (so to speak) with particles and hypervoxels.

The picture actually started life some four weeks ago. It was originally going to be poster-sized, with three Basestars in various states of explosion. As time went on and I continued to finesse the shells and fireballs, I slowly found myself losing interest. Rather than dropping the picture, I repurposed it, changing the camera angle and image size, losing one of the Basestars, and having only a little bit of explosion in the hopes it would finish rendering before I completed my higher education. I then did my customary Photoshop jiggery-pokery to make everything pop, along with a little film grain to set it all in and get rid of that CGI sterility.

I considered having some missiles coming out of the Basestars, but decided against it because, like I said, I wanted to be done. I'll make a missile setup later.

The backstory to the image is that it's from the battle in the flashback sequence of "Battlestar Galactica: Razor" (you can see it [url=http://www.youtube.com/watch?v=eQupz4WmExE]here[/url]) . Since the Cylons were focusing on the Battlestar Columbia, the other two Battlestars had the chance to switch from defensive to offensive fire, and this is their first salvo headed for the Cylon Basestars. Hence the reason for the quote, something later to be said by what these Cylons were fighting to the death to protect.

Comments

  • BigglesBiggles <font color=#AAFFAA>The Man Without a Face</font>
    Feel like running through how you used the particles and hypervoxels? I've never quite managed to figure them out.
  • David of MacDavid of Mac Elite Ranger Ca
    Sure. For the vapor trails, I created a null and parented it to the shell (which I had already animated at its speed), and under the "Dynamics" tab of object properties added the "Emitter" FX. Under [b]Generator[/b] I set a birth rate of 300 particles per second (the exact number depends on how fast your object is moving. You want enough so the trail isn't a gap-filled dotted line, but not so many it's just an opaque mess. Whether it's measured by second or frame doesn't seem to make a difference in how it behaves beyond the obvious, though I'm not sure how particles per "speed," "collision," or "wind" work).

    The generator size is fairly self explanatory. Make it big enough to fill whatever the trail is coming out of, but not so big particles are appearing outside it in empty space. Particle limit controls when your emitter stops emitting, and start frame when it starts. Interestingly enough, two particle emitters with the exact same settings will spawn particles in exactly the same way. If you have, say, a multiengine airplane, it's extremely apparent when it has identical vaportrails coming out of each engine, so you'll want to have each emitter have a different start time.

    Under the [b]Particle[/b] pane, the only interesting thing is "Life Time(frame)." This way, you can set when old particles disappear and stop using up your valuable memory. I set it to 300 frames, +/- 0. Everything else should be set to 0, as well.

    In [b]Motion[/b], "Velocity" should be 100%. I set "Explosion" to 5 m/s, so the particles would expand as the trail aged. I set "Vibration" to 5 m/s as well, so the trail would have a bit more life and randomness to it, instead of expanding uniformly.

    Under the descriptively named [b]Etc[/b] tab, I set "Position Blur" to 100, so the particles wouldn't appear in neat little discrete clusters but smoothly along the trail, and "Parent motion" to .5% so the trail would ever-so-slightly follow the shell it was coming off of. For a rocket exhaust, I'd set this to a negative value. For an explosion, I'd set it to 100%.

    And that's the end of the particle settings.

    After enabling hypervoxels, and activating my emitter null as a hypervoxel object, I set the object type to "Sprite" ("Volume" takes too long to render, and "Surface" is just a big blob). For "Dissolve," I went into the texture control and created a gradient with "Particle Age" as the Input Parameter. I set it so the dissolve would be at 0% at 0 frames old, and 100% at 300 frames old (at which point, the particle emitter would remove the particle from the scene, clearing a space for a new particle to be created. It's very "circle of life.") Particle size was set to 7 m, and likewise had a Particle Age gradient so it would get bigger in time, maintaining the integrity of the trail even as the particles drifted apart from each other. One of the key things to remember is that each particle is just a little fuzzy procedural-textured circle, but as long as they overlap, they look like natural, organic clouds. Lift them drift apart, though, and the illusion is shattered.

    "Shading" had every single channel described with a particle age gradient. "Color" had it start off the same yellow as the shell object, to represent its glow and flames, but faded to smoke gray within a few frames. "Luminosity" is, first of all, not actually equivalent to "Luminosity" in Lightwave's surfacing system. It corresponds to the diffusion channel, a concept that gave me a bit of trouble before I figured out what was going on in my test renders. Likewise, the luminosity was set very high for the first few frames, and went downward gradually after that. "Opacity" seems to correspond to "Transparency" and "Density" to "Translucency" in the Surface Panel, but in reverse. So a perfectly clear object would have 100% transparency, but 0% Opacity.

    I don't know why the Hypervoxels shading panel doesn't adhere to the conventions of the Lightwave surface editor but, then, I didn't design that damn thing, and it seems to work well enough once you figure it out.

    The shading panel also gives you the option to pick two lights that will be used on your hypervoxels, or to check a box to "Use All Lights." To save render times, each vapor trail had the main sun light and its corresponding shell light selected. "Use All Lights" isn't too bad for stuff like vapor trail, but a big smoke cloud in the middle of lots of lights like in [url=http://en.battlestarwiki.org/wiki/Image:Ep212battle.jpg]this shot[/url] will [i]kill[/i] your render times if you have "Use All Lights" turned on.

    Hypertexture should be "Turbulence," tuned to your standards of fuzzy cloudiness. Feel free to experiment on this. I certainly didn't.

    That's about all I have to say without going so far as to offer a formal tutorial. Clear as mud, right? Maybe I should put the scene and object up for download, and you can look at it yourself.
  • Random ChaosRandom Chaos Actually Carefully-selected Order in disguise
    I have to say I really like this :) - using it for my desktop background at work (suitably resized and cropped to fit my dual monitors).

    Just wondering - do you have a version without the text?
  • C_MonC_Mon A Genuine Sucker
    nice one! The film grain is a nice touch.
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