Produce a render for an advertising campaign

Create VFX for commercials with Lightwave and Houdini

Iñaki González breaks down an advertising project

The project I am going to break down here is a pitch for a commercial I did for an advertising agency in Barcelona, Spain. The campaign was about promoting a brand of still water, and the overarching theme was relating to the purity of this water brand as being like the water you may extract from a glacier. It was also important to find similarities to the legend of Excalibur, which has always fascinated me.

With this idea in mind, I decided to create a bottle made of stainless steel emerging from the ice, and cutting through it as if it was a sword.

This was a project that had several technical challenges, such as creating a pattern of ice that needed to look clean and believable when breaking, simulating this effect using dynamics, achieving the right look not just with the lighting but also with the shading, creating some smoke as the bottle is emerging, and then making sure that all the elements are glued together in the final composition.

Throughout my career I have used many different types of software and rendering engines, most of the time due to production demands, but currently my choices are Lightwave 3D, Houdini, Unreal Engine, Octane Render, Photoshop, Fusion 9 and Resolve, whenever I am running a team, or just freelancing.

Lightwave 3D was chosen for modelling, doing Bullet Dynamics, and also to run Octane Render. Houdini was used to create the broken ice geometry and also for fluid container dynamics. Compositing was done using Fusion Studio.

01 SET UP THE MODELLING BACKGROUNDS

It is very important to make sure your reference image has enough quality, allowing us to zoom into the details of its shape. If the image does not have the quality demanded for the modelling task, it will be really easy to miss details that are important when trying to achieve photoreal renders. Make sure you save your background with the right image and map it into a plane.

02 START DRAWING THE BOTTLE

Once we have set up a background reference to model from, and make sure we have saved it, use the Spline Draw tool to start adding points following the shape of the bottle. Spline Draw is a tool that’s really easy to use, you just need to add points and it will create an open curve by default. It has several really cool options, such as converting the first and ending points into control points, making the curve closed, or even resampling the curve and adding more points based on the existing ones.

03 ADD POINTS WHERE NEEDED

Spline Draw is a simple yet powerful tool. The idea is to draw the main points, and then resample and add more if needed. In order to create the right tension in between points, we will need to play with the distance between these points, as having them really close will give them more tension than having them farther away. This tool does not include control tangents; in case you need them, another tool can be used, Bezier, but it is a bit more complicated as it creates different curves that will need merging later on.

04 SET VALUE FOR AXES

We need to make sure that the first and last created points are over the Z or X axis, depending on how the reference image was set. We use Set Value for this, a tool that allows us to set a value in any of the three axes at the same time, guaranteeing us a ‘perfect revolution’ for the selected points. No selected points means that all points are selected.

05 REVOLVE THE CURVE

After creating the curve, we need to copy it into a new layer. If we do not do that, once the curve is ‘revolved’, the initial curve will be lost. We always want to work in the least destructive way possible, so make sure it is copied first. We use the Lathe tool to revolve the curve over Y and make sure the starting and end angles match 0º and 360º. Then set up a number of sides to get a smooth revolved mesh, and voilá! The cap mesh is done. Apply the same technique for the bottle’s body.

06 POLISH THE MESH

The base bottle is modelled but we still need to add some extra detail and clean the revolved mesh a bit. The Lathe tool freezes the original curve before revolving, generating an amount of polygons higher than what is needed for us. The Band Glue tool is great to optimise, clean, and keep the right amount of polygons. For adding detail and subdivisions, Band Saw Pro is also a great tool.

07 UV MAPPING

Once the model is finished, a UV map needs to be created. By default, the map will fit a 1:1 proportion, stretching and distorting the mesh. To solve this, we will use the cube trick. Create a cube that is bigger than the bottle, so when the UV map is created for both elements, the cube will be fitted in the 1:1 proportion, keeping the mesh of the bottle untouched in the UV space.

08 BASIC ANIMATION

Lightwave is a 3D software split into two different programs. Modeller is used to generate assets, and Layout is used to animate, light, shade and render. From now on we will be working in Layout. The animation for this project is very simple. We just need to move the bottle along the Y axis and maybe also rotate along Heading. Load the different assets generated in Modeller such the Bottle, Background, Ground etc, and animate the bottle. Once the basic animation is keyed, the curves can be tweaked in the Graph Editor.

09 LIGHTING SETUP

After creating the basic animation, before even adding dynamics, it is recommended to start setting up the lighting. Octane is a GPU unbiased renderer that helps us achieve photoreal results quickly, as it works with physically accurate lights and shaders. We add two key lights at each side of the bottle, and another one on top as a fill light – a pretty standard photo studio lighting rig.

10 SHADE THE BOTTLE AND ICE

The shader for the bottle is made using a diffuse material for the red label, and a glossy material for the metal. An Octane Material Mixer is added, using a mask made in Photoshop to weigh the balance of the different materials in the shader, and mix them. The ice is done using a specular material. Octane is great at handling reflection and refraction blurring, something that adds lots of realism to any render. In the ‘old days’ this was a really expensive calculation, adding bump maps based on distance, but the result was never as good.

11 FBX VS ALEMBIC

When working with hybrid pipelines where different parts of the project are done using different software, it is very important that animation, objects, and cameras all come together. The choice for this project was using Alembic. Alembic is great for handling complex animation as even Bullet Dynamics are exported properly. FBX is good when exporting cameras or objects, but not great when needing to export advanced animation. Make sure you doublecheck that the scene scale stays the same when exported.

12 GET READY FOR ICE CRACKING

With the scene inside Houdini, the ground is cracked but not simulated. I decided to generate the ground ‘cracked’ version in Houdini, using its procedural and node-based nature, and creating a tool to break the ground based on points scattered along the surface. The object is exported as OBJ and can be used in Lightwave 3D to simulate the breaks using Bullet.

13 BREAK THE ICE

Back to Lightwave 3D, in Layout, click FX Tools and make the bottle a Kinematic object. Then, make the cracked ground a Parts object. Tweak and test out the Dynamic Frame Rate setting under the World folder. Friction, Glue Strength, Breaking Angle and Breaking Distance will be the most important parameters to modify and get the ice broken nicely.

14 GEOMETRY INTO SMOKE

With the main animation, lighting and shading done, and also the Bullet Dynamics locked down, it is time to head back into Houdini and use the Smoke Solver to generate the VFX of the ‘emerging’ smoke. Smoke Solver needs a ‘density’ attribute (field) to start emitting from. VDB From Polygons is the tool to use, as it converts the geometry to voxels that are volumetric (3D) pixels. Start with a bigger voxel size and refine from there. Keep in mind that the size of the scene and objects is very important when dealing with voxels.

15 DOPS SMOKE SOLVER

Houdini works at different levels or contexts, and we have just scratched the surface and worked at SOP level until now. Dynamics are run at a different level, DOPS (Dynamic Operators), but it is possible to call them from SOPS using a DOP Network. The idea is to dive into Dynamics, get the simulation ready, and then import them back into SOPS using DOP Import Fields. To start running the simulation at DOPS there are three nodes needed: Smoke Object, Source Volume and Smoke Solver. Add Gravity to make the smoke fall.

16 RIGHT VOXEL SIZE AND NOISE

To set up the fluid container at the right size for the simulation, it is possible to use a Box geometry as reference and then use the same settings for the container. The voxel size needs trial and error, but starting from the voxel size set up in SOPS should be a good starting point. Gas Turbulence is used to add some variation and noise to the smoke.

17 IMPORT FIELDS FROM DOPS

The assets needed to start the simulation are done in SOPS. Then, the simulation is run in DOPS, and finally, it is brought into SOPS for rendering. To do that, a DOP Import Fields node is needed. It is important to make sure the right DOP Network and DOP node (Smoke Object) are selected, and that the Density field is chosen. Smoke Object will contain the simulation data. The Smoke Solver will compute the simulation that is stored in the Smoke Object, and the Source Volume node tells the solver where to simulate from.

18 SMOKE SHADER AND RENDERING

It is now time to add a shader and render it. Select Volume from the Material Palette folder. Choose Billowy Smoke and drag into the viewport, just over the simulated smoke. Billowy Smoke is a shader with two channels, Density and Temperature. Density will be the field to use. It is important to know that the same field can be used in both texture channels if needed.

19 THE POWER OF INSTANCING

Instancing is a technique of duplicating geometry at render time. Select some cracked pieces and save them as a separate object split into layers. Select the layer containing the ice cracks and add Instance Generator from Object Properties>instancer. Add as many layers from the object as needed, and change the Generation Type to Surface. Play around with the sizes and orientation until you are happy, and maybe animate some parameters such as scale to add even more variation. Make sure instances are in local mode.

20 OCTANE RENDERING PROCESS

In Lightwave 3D Octane works as a node-based system, and it is really intuitive. To begin with, just open the Octane Render Target and add a Direct Lighting as Kernel, a great option for testing. After testing and rendering a quick animation test if needed, it is recommended to change it to Path Tracing, as reflection and refraction blurring are handled better.

21 RENDER AOVS

Octane enables us to render separate buffers such as Direct and Indirect Diffuse, Direct and Indirect Reflection, Z Depth, Object ID etc. Add a Render Pass node and switch on the ones you need. Usually Diffuse, Reflection, Depth, Motion Vectors, Material ID and Ambient Occlusion are the ones to use in compositing. Make sure an output directory is set, that EXR Untonemapped is selected and hit Render. If instances are not updated change Rendering Scene Update Mode to Full Scene Reload from the Render Target options.

22 COMPOSITING

Fusion 9 is used for compositing the shot. I prefer it over Nuke as it has a very powerful free version, but also a final version in a price range suitable for freelancers or small studios. Drop a loader for every render and layer, and connect them using the Merge node. It is important to add a Gamut node at the end of the chain in order to set up a colour space and be able to preview it.

23 DEPTH OF FIELD

To have more control over the final look, but also to save us from high render times, it is better to add DOF in compositing. I really like the Depth Blur node, it works great! Just make sure the output from the loader of the Z Depth is connected to the Blur Image input, choose the Focal Point, and change the Z Scale. Tweak the Blur Size too if needed and correct with the Depth of Field slider.

24 USE VECTORS FOR MOTION BLUR

Utilising motion vectors is another compositing technique that can save our project when adding motion blur. The technique is based on adding colour to the image based on the change in position of the mesh, from one frame to the next one. The Fusion Vector Motion Blur node will use the RGB values or the Vector X and Y data to add motion blur over the image, and also applies it based on an intensity. Flipping channels is another option we can use when needed. •