We implement our models in PyTorch [45]. The network architectures for the geometry-, texture-, and deformation-
networks are illustrated in Fig. 7. We initialize the geometry network with geometric initialization [1] to produce a sphere
at the origin. For the deformation network, we initialize the linear blend skinning weights to have uniform weights for all
bones and the expression and pose blendshapes to be zero. For the geometry network, we use positional encoding [40] with
6 frequency components, and condition on a per-frame learnable latent code l ∈ R32.

Fig. 8 shows the modiﬁed geometry network for the C-Net, and the deformation network for the D-Net and B-Morph
baselines (see Section 4.2 in the main paper for deﬁnitions). We initialize the ablated geometry and deformation networks in
the same way as our method. The displacement output for D-Net is also initialized to be zero.

2.3. Ray Tracing
I M Avatar- Implicit Morphable Head Avatars from Videos