lightwave hellboy fire effect

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TUTORIALS | Pyrokinetic effects

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

LIGHTWAVE 3D

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

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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

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. www.redstarstudio.co.uk

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

060 | 3D WORLD February 2006

Pyrokinetic effects | TUTORIALS

STAGE ONE | The background plate and initial scene

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 > lwcontent and, from the Image Editor, load the plate image sequence. Make sure the start frame is set to 1 and not 0.

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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.

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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.

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STAGE TWO | Rotoscoping the 3D hand

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.

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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.

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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.

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EXPERT TIPView the whole frame

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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.

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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.

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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.

February 2006

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TUTORIALS | Pyrokinetic effects

STAGE THREE | Adding the particles

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.

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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.

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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 > Plugins (Additional) > FX Browser) and choose Start.

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EXPERT TIPDont move!

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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.

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.

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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.

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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.

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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.

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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).

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062 | 3D WORLD February 2006

Pyrokinetic effects | TUTORIALS

STAGE THREE (Continued) | Adding the particles

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.

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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.

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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 Tu