3d artist Voon Jiat Lim shared some techniques and tools that help him create amazing 3d visual effects.
I’m Voon Jiat Lim and I’m from Malaysia. I studied at Gnomon School of Visual Effects and my main focus is on VFX. I came from a generalist background, so I’m very familiar with all aspects such as modeling, animation, rigging, lighting, texturing as well as mel and python scripting. But VFX was the track that really got me interested, many people will think that its a very technical field but actually it can be very artistic too. Yes, it does have a very steep learning curve but after acquiring the basics skills such as manipulating data and particle motion etc. everything is artistic and based on your creativity to create amazing results.
I got really interested in VFX because I was always admired breakdowns of movie scenes and it inspired me to do it myself. After discovering Houdini, it opened so many doors for me. Having access to low-level data and manipulating them for abstract and controlled effects got me even more interested in the VFX field. I’ve also always been a fan of mathematics in school so having able to apply math in VFX just made my job that much more fun.
I always breakdown a shot to simple elements first then I’ll slowly layer complexity into it. Houdini is very procedural, so start simple first is important so you don’t spend too much time waiting for simulations and iterate faster. Not to mention looking for reference is key to making your shot looking realistic and believable.
As for the dragon fire shot, I’ve gathered mostly references from flamethrowers as they are the closest thing that I could think of to dragon fire. I emitted a stream of particles as fuel to achieve the liquid fuel spraying look, on top of that I’ve also emitter more particles coming out of the stream to introduce more density and temperature.
Some artistic choices were made of course to reach a much more interesting looking fire, I started with just flames and no smoke but after adding thick rolling smoke it added so much to the overall look of the fire. With my experiences in pyro effects so far, I find the most important part comes from the way you create the fuel source as well as particle movement the more interesting your source is the better the result is.
When I was animating the dragon I also made sure it has enough head movement to create an interesting spray, not too big that the container gets out of control. The animation and rigging were fairly simple and I’ve used nCloth for the wings and webbing of the dragon.
Constituent parts of the flame
I gathered tons of references for flames and I like to experiment different shading curves for a different result. Most of the time flames have bright and dark areas, having a sharp spiky curve can achieve that look. Also visualizing the temperature field in Houdini is important, it tells you the motion of your flame and whether it dissipates properly. The micro-solvers in Houdini is really helpful for achieving looks that you desire. I usually create a big and a small turbulence field and use different control fields as masks, depending on the effect that I’m going for. Turbulence is a great breaking up tool to remove the generic mushroom cloud look. I use disturbance at the very end just to kick in some details after I’m happy with the overall motion of the pyro sim.
As for lighting I usually split them in a different render layer just so I have more control in Comp. I create a Key, Fill and Rim light(depending on your scene) and render them Red Green and Blue respectively so I can extract them separately later in Nuke.
I was experimenting with FractureFX and I love the way it’s set up with layers of rules you can have for your simulation, such as breaking the glass first upon the impact of the missile before the concrete. Using a Maya Plugin is useful when you are trying to render in Maya, it saves you the trouble of transferring the simulation from one program to another.