How MPC created the tree monster for A Monster Calls film

MPC created the transformation and intricate anatomy of the monster in Juan Antonio Bayona’s A Monster Calls film, as well as Conor’s neighbourhood and set extensions for the final cemetery scene.


MPC worked on the close-up scenes between main protagonist Conor O’Malley and the titular monster in A Monster Calls, modelling and adjusting the monster’s facial expressions and anatomy, as well as the environments for Conor’s neighbourhood and rooftop of his house.

A Monster Calls, directed by Juan Antonio Bayona, is based on the original novel written by Patrick Ness. It follows Conor’s (Lewis MacDougall) moving journey of dealing with his single mother’s terminal illness with the help of a tree monster. Watch the trailer here

MPC Montreal VFX supervisor Ferran Domenech oversaw the team’s work on more than 180 shots.

MPC modelled the monster’s full body for the transformation and close-up shots throughout the film, mainly working on dialogue scenes of the monster (voiced by Liam Neeson) against the performance of Lewis MacDougall.

The VFX company also created the monster’s transformation from a small Yew tree into the monster and his bigger and scarier version, with an internal fiery glow and protruding spiky branches.


MPC modelled and adjusted the monster’s facial anatomy from the original head scan supplied from production and modelled and textured the whole body, which is made up of different types of wood pieces intertwined with branches and vines.

These were then rigged to articulate and simulate a musculature and nervous system – with the facial rig requiring the most research.

The whole face of the monster was built as a jigsaw of hundreds of sliding pieces that would neither stretch nor deform like rubber, but instead slide alongside each other. This allowed for a wide range of expressions and lipsync dialogue whilst keeping the nature of rigid wood pieces.

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The monster’s eyes were a vital way to portray emotion. MPC designed them to resemble human eyes whilst keeping a natural tree-like base quality at its root.

To do this, MPC used textures from lighter wooden surfaces on the sclera, with the colour palette of the iris derived from the moss covering the monster’s body, and the wet areas of the eyes based on different types of tree sap.


MPC also worked on the final nightmare cemetery sequence, in which MPCs FX and technical animation departments created destruction elements and destroyable props.

The technical animation department added wind simulations to the small branches that sprout from the monster, and added leaves and bark that would fall when the monster transformed from a normal Yew tree into the 40ft tall monster.


The close-up performances of the monster were animated as full keyframe shots both for body and facial acting. 

This was realised with a wide selection of directed video references of Liam Neeson for each scene, although no motion capture data was used in the finals shots.

The video sessions were used as guidance for the animators as they worked with the audio. This can be seen in the final scene when the monster helps Conor face his nightmare, delivering an emotional performance based on real-life.

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