  Measured Bidirectional Texture Function (BTF) can faithfully reproduce a
realistic appearance but is costly to acquire and store due to its 6D nature
(2D spatial and 4D angular). Therefore, it is practical and necessary for
rendering to synthesize BTFs from a small example patch. While previous methods
managed to produce plausible results, we find that they seldomly take into
consideration the property of being dynamic, so a BTF must be synthesized
before the rendering process, resulting in limited size, costly pre-generation
and storage issues. In this paper, we propose a dynamic BTF synthesis scheme,
where a BTF at any position only needs to be synthesized when being queried.
Our insight is that, with the recent advances in neural dimension reduction
methods, a BTF can be decomposed into disjoint low-dimensional components. We
can perform dynamic synthesis only on the positional dimensions, and during
rendering, recover the BTF by querying and combining these low-dimensional
functions with the help of a lightweight Multilayer Perceptron (MLP).
Consequently, we obtain a fully dynamic 6D BTF synthesis scheme that does not
require any pre-generation, which enables efficient rendering of our infinitely
large and non-repetitive BTFs on the fly. We demonstrate the effectiveness of
our method through various types of BTFs taken from UBO2014.
