ToF ReSTIR: Time-of-flight rendering with spatio-temporal reservoir resampling

1Dartmouth College

In ACM Transactions on Graphics (Proceedings of SIGGRAPH), 2026

Teaser
We propose a real-time Time-of-Flight (ToF) rendering method inspired by ReSTIR, a state-of-the-art technique for steady-state real-time rendering, augmented with a novel path-length-aware shift mapping. (A) Compared to conventional path tracing and naive path reuse adapted from steady-state ReSTIR [Lin et al. 2022], our method produces improved visual results for both time-gated image rendering and transient histogram rendering in dynamic scenes at interactive frame rates. (B) We further demonstrate two interactive downstream applications enabled by our renderer. For non-line-of-sight (NLOS) reconstruction, we recover hidden voxel geometry using temporally focused imaging [Pediredla et al. 2019a], where time-gated image simulation with our method reliably reconstructs the shape of the teapot. We also simulate NLOS navigation tasks [Young et al. 2025], where the reduced noise in our rendered transient histograms enables robust neural network inference and reliable path planning, whereas baseline methods fail to produce safe paths due to noise.
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Abstract

We present a novel spatio-temporal reuse framework for time-resolved light transport, enabling efficient Monte Carlo rendering of time-of-flight (ToF) phenomena such as time-gated imaging and transient light capture. Existing ToF rendering methods are computationally expensive, scale poorly to complex dynamic scenes, and are therefore unsuitable for applications with strict latency constraints. To address this limitation, we draw inspiration from ReSTIR, a reuse-based technique for steady-state real-time rendering, and adapt its core principles to interactive-rate ToF simulation. However, naively applying existing ReSTIR methods to ToF rendering leads to severe inefficiency, as reused paths frequently violate optical path-length constraints and thus contribute little or no signal. We overcome this challenge by introducing a path reuse formulation that explicitly enforces physically valid optical path lengths. The key idea is path-length-aware shift mapping, a geometric transformation based on Newton's method that adjusts reused light paths to satisfy temporal gating constraints, inspired by specular manifold exploration in steady-state caustics rendering. The resulting framework substantially improves the efficiency of ToF rendering across a wide range of scenarios, including complex scenes with glossy or specular materials and dynamic motion. Our method supports both time-gated and transient rendering at interactive frame rates, enabling simulation under practical latency constraints. We demonstrate the effectiveness of our approach through two downstream applications, including shape reconstruction and navigation.

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Juhyeon Kim, Wojciech Jarosz, Adithya Pediredla. ToF ReSTIR: Time-of-flight rendering with spatio-temporal reservoir resampling. ACM Transactions on Graphics (Proceedings of SIGGRAPH), 45(4), July 2026. 
@article{kim26tof-restir,
    author  = {Kim, Juhyeon and Jarosz, Wojciech and Pediredla, Adithya},
    title   = {{ToF} {ReSTIR}: {T}ime-of-flight rendering with spatio-temporal reservoir resampling},
    journal = {ACM Transactions on Graphics (Proceedings of SIGGRAPH)},
    year    = {2026},
    month   = jul,
    day     = {23},
    volume  = {45},
    number  = {4},
    doi     = {10/rrcp}
}
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