This is an account from the beginning concept to the final compositing of the grand finale of the Helios preview video. This single scene became such a powerful example that the Helios software was rewritten to include a smoke plume cloud type.
This is the Helios “hero image”. Having a soft spot in my heart for volcanic things, a personal goal in building Helios was to have all sorts of clouds, not just those that float in the sky. In Vue, creating thunderheads has been just as hard as creating a realistic plume of smoke. Having seen various volcano “burps” - and with having QuadSpinner’s co-founder, Cynthia Najim, living right next door to the youngest and most active volcano in Central America - we had more than enough visual reference to take on this beast of a task.
The final image of a trailer has to be a finale in every sense of the word. We were searching for the perfect piece to end the Helios trailer with. It needed to represent the core values of the software. But the volcano was never in mind for that finale. The volcano started as an experiment in just how far we could push the clouds in Helios. The image below shows the first incarnation of the smoke.
Created using the same logic that was powering normal Cumulonimbus (Cb) in the library, this Plume cloud (Pl) was extrapolated as a new type. Instead of focusing on lateral movement like a Cb, the Pl goes upwards and expands. Normally, you work with multiple settings to scale different features of the plume, but with the Pl Cloud Type in Helios, you simply have a command called “Grow”. This takes care of growth in terms of height, thickness, subvapor light intensity, detailing of cloud features, and more.
Rather than using a one-size-fits-all approach, we divided each Cloud Type (read more about the types on the Helios website) into separate logic sets. In other words, we don’t apply the same settings or the same rules to all the cloud types. Cloud types (in nature) are diverse and their uniqueness needs to be captured accurately in the type of settings we expose for them.
The darker image above represents a fully formed Plume (Pl) cloud type. The coloration and Subvapor Lighting are treated differently without having to apply a new color tone.
To experiment with this new cloud type, I took it into a volcano scene where it was placed in the center of the cone and expanded as the volcano was erupting. The color hue was changed to look like smoke/ash and mud particles instead of an intense black smoke. You can also notice how the Pl cloud is interacting with the EcoSystem instances at the base by softly engulfing them.
The animation was working out quite well, but the setting needed a deeper dramatic tone. The volcano was made completely barren instead of having some vegetation on it. The visual toning went from bright blue day skies to a dark overcast night, with intense reds and browns controlling the entire palette. New explosive lighting and details were added to the Pl cloud by setting up a large number of Quadratic Omni lights in the cone of the volcano.
Dark cloud cover was added to complete the mood of the image – at least for the pure 3D portion. Certain final lighting changes were made to make the image easier to work with in post-production. Once all the elements looked good, the scene was rendered in multipass to isolate the cloudy sky (Cs), the erupting volcano plume (Pl), and the volcano terrain itself. In post-production, video footage of colored particles was overlaid.
Finally, a color correction pass and some lighting effects were added to complete the animation.
This entire process was finished in a few hours. It was apparent to everyone on the team that this would be the defining image of the trailer. Large modifications were made to the trailer itself to have the impact of the volcano deeply integrated into the sequences. The particles took on a more prominent role as intro and outro for the trailer. We also re-sequenced the order of shots to flow better in terms of motion and color as the viewer was taken from one image to the next, resulting in an intense eruption at the end.
A video breakdown of this process is available on the Helios website in the Compositing section. The finished product can be seen at the end of the Helios preview video.
The volcano scene was too powerful and exciting to not expand upon. Currently, the scene is being extended to include more visuals and will eventually end up as a key pivotal shot in a future animation project. Keep checking back for updates.