With Strings Attached Breakdown

With Strings Attached is a 3D animated short film by graduating senior Jerika Melgar in which I was tasked with rendering, editing and final exporting. Upon reviewing the set and shots, my head was flooded with ideas for cool lighting. Consequently I proposed to relight the project in addition to my other tasks. This was my first foray into lighting for animation and presented a number of challenges.

For better or for worse, I decided to take charge of the visual look of the project upon receiving the first round of animation. Jerika had no plan for lighting, other than the established set lighting that was done by another student previously, which I personally found flat, boring and impractical to render for animation. Having done a significant amount of lighting design for film productions in the quarters before, I felt I could do better.

Previous established lighting. Original modeling, texturing and lighting by Michael Devore.

Since the set was a treehouse, I envisioned a dark blue ambiance with bright streaks of light shining through gaps in the wood creating interesting shadows andeffects. Reference imagery was collected and I got approval to proceed.

Samples of photographic reference collected, various authors.

Out of 25 total shots, a single shot was selected as a pilot for getting the workflow down. This shot contained one of the characters and a good amount of the set in focus. I spent more time on this shot than any other, but the time was well spent developing the look and ironing out issues.

The existing texturing had to be reworked significantly to achieve realistic lighting. I ended up replacing nearly all textures and developed a wood shader I used on most everything. Also changed was the outside environment – previously just a solid color. An area of the set near the protruding tree trunk had a sphere with foliage, but this was not sufficient for other shots that looked out other windows. In addition, I wanted the foliage to have some life and movement, so I ditched the environment spheres completely and shot some video plates of trees outside of my house. These were color corrected and composited into the shots later on.
Video plate of foliage, final composite with foliage in background.

In order to add some life to the set itself, I played with some ways of getting the light to move around as if it were shining through moving branches and leaves. I ended up creating two planes that had a foliage alpha channel and moved them around infront of the sun light in Maya. This worked to an extent but broke down in shots that had the characters in full frontal sunlight. Ultimately more R&D time would have been helpful to iron out the issues.

To create the splashes of light as seen in the reference imagery, I used the existing set structure and simply shined a light in from outside. By removing or adding specific wood panels, creating gaps here and there, interesting patterns were created and I had a fairly good amount of control over where the light was falling. This allowed the characters to always have some pattern of light on them, even if the set was relatively dark, creating moody contrast and depth.
The set wall which light was directed through. Although never visibly seen, each gap was placed to provide a specific streak or splash of light.
Streaks and splashes of light illuminated the characters but keep the environment dark and moody, helping to drive the story.

In lighting for realistic projects, I normally use Final Gather to provide secondary diffuse bounces. The intent was to use it onĀ With Strings, however, I found that rendering Final Gather was prohibitively expensive time-wise for 25 shots. I used a Final Gather-rendered reference frame and lit the set without any global illumination at all, placing bounce lights to mimic what I saw in the fully-rendered reference. This decreased render times per frame from 45 minutes to about five minutes. It was easier to get away with faking global illumination because of the stylistic splashes of light approach. The original set, pictured previously, lighting relied almost entirely on global illumination and two overhead lights.
Bounce and fill lights were key to creating economical lighting.
A solitary splash of light barely illuminates the main character once he is broken and abandoned.

In addition to complex lighting, mastering the project in 1080p was a contributing factor to the render time. Unfortunately there was no way around this, as the depth render pass used to compute depth of field had to be rendered at a very large resolution. The main beauty render pass also had to be at least 1080p for the post-processed depth of field to work without artifacts. The post DoF technique proved effective, however, as rendering depth of field baked in the beauty pass would have pushed the render time even further.

Motion blur was employed on many shots, though I had to be very selective because it usually increased render time by a factor of two. When it was not needed, it was not used.

25 shots were delivered fully lit and rendered. Lighting for character animation was a fascinating experience, as was taking knowledge of film lighting and applying it in a different way.

  • The Pipeline
    • I set up a rigid directory structure and had no problems referencing files or transferring my assets to the renderfarm.
  • Using Reference to Develop Style
    • Finding and presenting reference images gave a clear goal and guide.
  • More tests for R&D
    • I took one shot to completion first and spent a lot of time on it to iron out issues, but I should have selected an additional shot of a different style. Problems such as the moving foliage through light were only apparent in certain shots. Unfortunately there wasn’t much time to rework what I had.

4 thoughts on “With Strings Attached Breakdown

  1. Adi

    Hey Stephen, Great job on the breakdown. I was wondering what technique you used for rendering the light fog?

  2. Jacky

    Doesn’t really look like it’s mainkg contact with the floor on the first bounce imo. There should be a smaller shadow under it like there is on the second bounce and trough the end.But I am looking forward to the tutorial and the render looks sweet.

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