Lightwave Hellboy Fire Effect

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<p>TUTORIALS | Pyrokinetic effects</p> <p>Fire at your ngertipsFACTFILEFOR LightWave 3D 8+ DIFFICULTY Intermediate / Expert TIME TAKEN 2-10 hours ON THE CD Full-size screenshots Background footage LightWave scene les Finished shot ALSO REQUIRED A compositing program such as After Effects</p> <p>LIGHTWAVE 3D</p> <p>Running into a dead end is no fun at all, so it helps if you have the power of LightWave 3D at your ngertips to blast a hole in the wall. We show you the best way to generate the necessary superheroic VFX BY BENJAMIN SMITH</p> <p>O</p> <p>ne of the best bits in superhero movies such as Hellboy and the X-Men series is where a character has the ability to cause re to spew forth from their hands before hurling an</p> <p>track a 3D model of a hand into the scene, which will then serve as an emitter for particles that will lap around the hand and spiral upwards. Volume HyperVoxels will enable us to render the particles as an ethereal blue ame, and well use After Effects to composite the render back into the background footage, enhancing it a little to t the scene better. Most of the actual work will be done with LightWaves particle tool, ParticleFX, and since well be using collisions, calculating the simulation will probably be quite slow and somewhat unstable. For this reason, we strongly suggest saving the scene as my_scene_ v001.lws and using the Incremental Save feature to save a new version every few minutes. Benjamin Smith is Creative Director of Red Star Studio, a digital lm production company. Sadly, his own superpowers are limited to leaping tall kittens in a single bound.</p> <p>almighty aming ball at their nemeses. Its certainly a handy superpower, and we can only hope that these people are sensible enough to ask someone else to ll their car up at the petrol station. In this tutorial, well show you the safe way to recreate this fantastic pyrokinetic effect. Helping us with the drama is a lovely mademoiselle, who has gleefully posed for a brief video clip, running down a deserted corridor and screeching to a halt before summoning up her dark powers and throwing a powerful blue thunderbolt presumably at someone whos stolen her jar of Nutella. [Pardon? Ed.] The visual effects, of course, step in where our heroines powers end: creating the reball and the wisps of blue ame that spring from her palms as her power builds. Well use LightWave 3D to</p> <p>060 | 3D WORLD February 2006</p> <p>Pyrokinetic effects | TUTORIALS</p> <p>STAGE ONE | The background plate and initial scene</p> <p>Locate the Fireball folder on this issues CD and copy it to your computer. Inside, youll nd a JPEG image sequence that makes up the background plate for the shot, as well as a lo-res QuickTime movie. Load LightWave Layout, set the content folder to Fireball &gt; lwcontent and, from the Image Editor, load the plate image sequence. Make sure the start frame is set to 1 and not 0.</p> <p>01</p> <p>From the Compositing tab on the Effects panel, set the plate as the Background Image. In the Display panel [D], set the Camera View Background to Background Image. Set the scenes end frame to 320 and scrub the Time Slider to see our heroine go through her motions in the Camera view.</p> <p>02</p> <p>Set the Camera Zoom to something like 4.3 (roughly a horizontal eld of view of 35 degrees), and move it to about 1.5m in Y. Rotate it so the horizon and perspective in the grid approximates that in the plate.</p> <p>03</p> <p>STAGE TWO | Rotoscoping the 3D hand</p> <p>To create re ying from our models hand, well need to rotoscope a 3D hand over her own and use it as an emitter for particles. Enter Modeler and load hand.lwo from the Objects folder. This is a generic hand model with a simple skeleton already set up.</p> <p>04</p> <p>Load hand.lwo into Layout, convert the bones layer to Skelegons and set the hand geometry to use these bones to deform. You can now move and rotate the tiny root bone of the hierarchy to match the position of the models hand.</p> <p>05</p> <p>Start at frame 220. Position the root bone over her wrist (you can see her watch, which is a useful guide) and rotate Bone01(7) to ex the hand into position. You can roughly select and rotate the nger bones into position, too.</p> <p>06</p> <p>EXPERT TIPView the whole frame</p> <p>i</p> <p>Step forward 10 frames and move the hand to keep it loosely in position. Repeat this at each 10-frame interval throughout the sequence, so the animation is blocked out. The tricky bit comes around frames 250-280, where she pulls her hand back and shoots it forward. Make sure you move the hand back and forth in Z enough so that it scales with perspective.</p> <p>07</p> <p>Once youve got the position of the hand roughed out in 10-frame intervals, you can go back and ne-tune the position of the ngers to match the live action. You can then start lling in keyframes where necessary between the 10s, so the 3D hand remains locked over the live action throughout the shot.</p> <p>08</p> <p>With the 3D hand superimposed over our heroines own hand, its hard to see what shes doing with her ngers. Refer to the background image by going into the Image Editor, making sure Use Layout Time is on and double-clicking the thumbnail image sequence. The current frame opens. Since playback of the scene is jerky with the plate loading in the background, make a preview if you need to watch the animation back to check it. Alternatively, just load the reball_roto.lws scene from the CD to get to this stage.</p> <p>February 2006</p> <p>| 061</p> <p>TUTORIALS | Pyrokinetic effects</p> <p>STAGE THREE | Adding the particles</p> <p>With the hand nicely rotoscoped, you can start adding some particles. In Modeler, select the hand object, then copy and paste it twice into two other layers. In the rst layer, delete the polygons around the wrist and use the Smooth Scale tool to expand the hand by about 3mm. Name the layer Emit.</p> <p>09</p> <p>Shrink the second copy of the hand by a few millimetres and name this layer Collision. Both layers are automatically added to Layout, and you just need to set them to use the bones from the Skelegons layer to animate them. From the hand_emit objects Properties panel, add FX_Emitter on the Dynamics tab.</p> <p>10</p> <p>In the ParticleFX panel, the Nozzle should already be set to Object-Surface. Set the Birth Rate up to 500, the Particle Limit to 2,000, activate Fixed and set the Start Frame to 180. Hit either the Calculate button on the Dynamics tab or bring up the FX Browser (Utilities &gt; Plugins (Additional) &gt; FX Browser) and choose Start.</p> <p>11</p> <p>EXPERT TIPDont move!</p> <p>i</p> <p>LightWave 3D 8.3 locks up the computer while simulating particles, so once youve pressed Start or Calculate, its important not to touch anything else in the program, or to try to switch to another application or process. This will crash LightWave, so resist the temptation to check your email! You can quit the particle simulation by pressing [Ctrl] for a few seconds if you really need to do something else. Thankfully, this bug has been xed in LightWave 8.5, which also has a handy progress slider for dynamics calculation on the FX Browser.</p> <p>The trail of particles looks great, but it should really drift upwards. Add a Dynamics Gravity object and simulate again to see the particles drift up. You can add some randomisation by setting variations on Weight and Resistance with the +/ elds on the emitters Particle tab, as well as a tiny bit of Vibration on the Motion tab.</p> <p>12</p> <p>Where particles are born under the hand, they now immediately pass through it upwards under gravity, so we wont get any re lapping around it. To resolve this, select the hand_collide layer. On its Properties panels Dynamics tab, apply FX Collision and open its panel.</p> <p>13</p> <p>Set the type to Object-Subdiv and Bounce/Bind power to 100. Simulate again and this smaller collision hand will repel the particles created just outside its surface by the slightly bigger emitter hand, causing them to lap around the main hand. You can set Roughness in the Collision panel to 50% for variation.</p> <p>14</p> <p>Once the re has started burning from the models hand, it shoots upwards and away. We want it to spiral in an organic, ame-like way, so well add a couple of Wind objects to propel the particles. However, we want these effects to be located around the middle of the hand.</p> <p>15</p> <p>Add a null and call it parented_to_bone. On its Motion panel, add the Follower plug-in and set Item To Follow to be a suitable bone in the hands palm. Turn on World Coordinates and turn off the HPB rotate and XYZ scale options (by setting Source to None). The null will now follow the position of the hand, but will remain oriented vertically (because it isnt inheriting rotations).</p> <p>16</p> <p>062 | 3D WORLD February 2006</p> <p>Pyrokinetic effects | TUTORIALS</p> <p>STAGE THREE (Continued) | Adding the particles</p> <p>Add a Wind, call it spiral_wind and parent it to the parented_to_bone null. Set the Wind mode to Rotation(Y), the Radius to 150mm and Spiral Amount to 100%. Simulate and youll see the particles rise with a slight spiralling motion. You could turn this Wind off (tick the box next to FX_Wind in the Dynamic tab) to see the results of other Winds without being affected by this one.</p> <p>17</p> <p>Add another Wind, call it vertical_wind and again parent it to parented_to_bone. Set this Winds mode to Cylinder-Explosion, its Radius to 250mm and Power to 50%. Simulate and youll see that this Wind causes the particles to be sucked inward toward the middle of a cylindrical effector, so they seem to rise in a column without spreading out so much.</p> <p>18</p> <p>Add another Wind and call it turbulence_wind. Leave it at the origin and, on its panel, set Mode to Turbulence and turn off Falloff. Use the Vector tab to set the Turbulence Size XYZ to 500mm and make Turbulence Vector X 1m. This Wind adds a random motion that helps to add more organic twists.</p> <p>19</p> <p>Load particles_nal.lws to see the nal particle animation created for the shot. We applied a few more tweaks to add some extra detail and to x any problems. We also animated the emitters Birth Rate so the re cuts off once the reball is released, and added a little random variation during the rest of the shot.</p> <p>20</p> <p>We found that we had to turn the collision with hand_collide object off at certain points (like when the hand moves violently through the frame) to prevent particles bouncing around like crazy. Add an envelope to the Bounce/Bind power, and keyframe it down to 0% if you experience any strange behaviour.</p> <p>21</p> <p>We also created the actual reball, which is straightforward compared to the trail of re a particle emitter simply shoots out of our characters hand at the appropriate moment, leaving a trail of particles that are rendered with HyperVoxels.</p> <p>22</p> <p>STAGE FOUR | Render settings for HyperVoxels</p> <p>In the HyperVoxels panel, activate the hand_emitter layer, set Object Type to Volume and open VIPER to render a quick particle preview. On the Geometry tab, set Particle Size to about 40mm and Variation to 50%. On the Shading tab, set Color to a suitable shade of blue, Opacity to 25% and Thickness to 5%. On the HyperTexture tab, choose the Crumple texture.</p> <p>23</p> <p>You can use the Preview pop-up in VIPER to create a lo-res preview to check how the effect looks in motion. Particles tend to pop into and out of existence, so you can use Gradients to control and rene the effect. Apply a Gradient on the Particle Size, set to Particle Age (so the particles are 0 per cent when theyre born), scale up really quickly and scale down as they get older.</p> <p>24</p> <p>It may take some tweaking to get the HyperVoxels looking really good, and the render time for the sequence can be quite long. You can load the reball_nished LightWave scene from the 3D World CD to see our nal settings..</p> <p>25</p> <p>February 2006 3D WORLD | 063</p> <p>TUTORIALS | Pyrokinetic effects</p> <p>STAGE FIVE | Compositing in After Effects</p> <p>In After Effects (or the compositing package of your choice), start a new composition at 640x480 (square pixels) and 25fps. Import the background image sequence and the rendered re element, layering the render over the background (remember that the render only begins at frame 170).</p> <p>26</p> <p>Now copy and paste the re layer, select the lower layer and apply a Blur lter to it. Blur it by about 100 pixels until you have a vague blue blob, and then set the Layer Blending mode to Screen. This will add a blue halo around the re, so it seems to light up the screen and nearby objects.</p> <p>27</p> <p>You can duplicate the re layer again and apply a Brightness/Contrast tool to darken it until only the brightest areas of the scene remain. Blur this and layer over the original with the Blending mode set to Screen. This creates a highlight glow that seems to spill around the edges of the models ngers.</p> <p>28</p> <p>The background video is extremely noisy (it was shot in low light), whereas the rendered re is totally clean. Add a Noise lter into the re effect using its Alpha channel as a mask, and match the noise against our models dark surroundings.</p> <p>29</p> <p>We also added camera shake to the nal shot. Create a new composition and drag the rst composition into it. You can now expand the motion options for the clip in the composition, scale it up a tiny bit and add keyframes for position and rotation to simulate shake.</p> <p>30</p> <p>As always with a composite, its the extra touches at the end that really help to sell the nal result. If you look at the on the CD, youll notice that weve added a few extra sweeteners to this scene, such as the lens are that comes from the reball when its at its peak intensity. After Effects has a standard Photoshop-like lens are generator that works just ne, but</p> <p>31</p> <p>for this effect (pictured above), we used the excellent Knoll Lens Factory suite of plug-ins to make a really impressive are that sends reections across the shot. Alternatively, you could create this kind of effect by parenting a light to the reball emitter in LightWave, turning on Lens Flares to render it as a separate pass, and then compositing it in. All of these methods will produce a great nishing touch. </p> <p>064 | 3D WORLD February 2006</p>