Since Monster House was basically an animated horror film, it was important to maintain the intensity of the scary moments in the characters’ expressions and body language. One common theme throughout most of the film, which was especially true of the scarier sequences, was the application of what the crew came to call the “trapezoid mouth.”

“While the mocap facial data was actually pretty faithful to the literal position and shape of the mouth in general, an extremely distressed mouth expression usually had to be enhanced manually into a trapezoid shape,” Hofstedt notes. “There was a breakthrough shot early in the production where Chowder is yelling for help. The first version was OK, but Chowder’s mouth looked rather mild and rounded. The actor’s mouth on the take was convincing for a human, but for a stylized animated character, it was missing the intensity. So animation supervisor Troy Saliba did a sketch that had the mouth corners pulled down, the lower lip fairly flat straight across, and the upper lip with a couple of distinct corners, hence the trapezoid mouth was born. This technique became a shorthand approach throughout the film to add an extra level of intensity to shots where there was fear or distress onscreen, which basically was about 85% of the movie.”

The House itself was 100% keyframed (as was the dog). With this character, the animators had to strike a delicate balance in the way the House moved. It needed to feel heavy and massive, yet it also had to be maneuverable and energetic. Although animators had the ability to add squash and stretch to the animation, they strove to keep it subtle in order to maintain the rigidity of the materials.

One epic shot near the end of the movie has DJ swinging around at the end of a cable dangling from a crane swinging around a construction site. Animating the camera move alone on that shot took several artists a few days… “There was a very complicated choreography of managing the constraints between the camera, the character and the environment,” Hofstedt recalls. “Sometimes the camera had to follow DJ, sometimes it had to follow the dynamite, sometimes it had to aim at the House, and sometimes the camera drove the action. There was a careful blending between each constraint switch as to appear seamless onscreen, all the while managing the switches in speed and direction. And none of the animation could be finished until the camera got locked down…”

 

Film Noir Influence
When time came to address lighting issues, Redd’s background in photography and cinematography became a strong asset for the production. “Monster House is a dream film for a lighter, it’s a scary adventure and, therefore, demands strict visual storytelling. For this movie, the shadows were just as, if not more important, than the light. In creating mystery, one has to be very conscious of not revealing too much too soon. Creating dramatic lighting requires heavy contrast, hot hots, dark darks — but also the choice of color plays an important role. Some colors appear to have more luminance than others, and you have to balance that by light angles and shadow softness. I tried to take a photographic approach as the starting point, and then added the necessary drama to create interest and tension in a scary scene. I took my crew down to a stage and lit a physical miniature set with different style lights, gels, smoke effects, etc., to get everyone on the same page stylistically. Again, in creating our unique universe, we always kept the ‘miniature set’ feel in our minds — this comes through as shallow depth-of-field, blown-out highlights, and subtle falloffs with shadow edges.

“We developed new rendering technology with Marcos Fajardo at Imageworks. The first day Gil Kenan and I met, back in Feb. 2004, we both talked about how much we loved stop-motion films, and how we wanted to make a movie that looked like it was shot on film, but using all the modern miraculous technology. So for me, light quality was an absolute key ingredient. The simplest thing to create reality in a CG image — bounce light. Indirect colored diffusion. It’s what makes a plastic dollhouse still look ‘real.’ We mostly stayed away from ambient occlusion, because it doesn’t incorporate color into its calculations. We chose our characters’ skin to look more like high-density foam or clay. We didn’t want to introduce any materials that tried to feel like human skin or hair. Digital effects supervisor Seth Maury and I spent many weeks mapping out and testing sun color, shadow color, shadow length, etc. as this was all important to the passage of time in the film.”

Other software packages used on Monster House included Maya for modeling and animation, Maxon BodyPaint and PhotoShop for texturing, and Houdini for many of the effects and natural phenomena. The crew also developed a sprite renderer called Splat, that allowed them to create seemingly rich and deep volumetric effects efficiently. These smoke and dust effects appear throughout the movie. The shots were composited with proprietary software Bonsai.