Instant Neural Graphics Primitives with a Multiresolution Hash Encoding
ACM Transactions on Graphics, 2022 · paper · Computer science
Introduces a multiresolution hash-table input encoding that lets a small neural network represent graphics primitives, implemented in fused GPU kernels. It enables training in seconds and rendering in tens of milliseconds at 1920×1080.
Checked: PDF from arxiv.org, fetched 4 Oct 2026. Page numbers are those of that PDF.
1 finding
Substance The Fig. 2 caption says encoding (e) "trains over 8× faster" than (b), but the printed times are 12:45 for (b) and 1:48 for (e), a ratio of about 7.1×.
- p. 3 Fig. 2 caption and panel labels
trains over 8× faster
- p. 3 Fig. 2 panel (b) and (e) labels
12:45 / PSNR 22.90
- p. 3 Fig. 2 panel (e)
1:48 / PSNR 22.61
Only the authors can say what is right here.
Judge's note: I read the labels under the panels on the p.3 image: (b) 438 k + 0, 12:45 / PSNR 22.90; (e) 10 k + 494 k, 1:48 / PSNR 22.61. 765 s / 108 s = 7.08. The caption names (e) and (b) explicitly, and rounding cannot close the gap to 8. Either the caption factor or one of the printed times needs revising, and only the authors can say which.
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22 minor (typos and the like; most checked by the judge only)
Reference or label Section 2 cites "attention components of recurrent architectures [Gehring et al. 2017]", but the reference-list entry is "Convolutional Sequence to Sequence Learning" (ICML'17), a convolutional model.
- p. 2 Section 2, paragraph 2
attention components of recurrent architectures [Gehring et al. 2017]
- p. 12 References
Convolutional Sequence to Sequence Learning
- p. 2
tion components of recurrent architectures [Gehring et al. 2017]
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: that the Gehring et al. ConvS2S model is non-recurrent; its title in the reference list (p.12) does say 'Convolutional'. The p.2 text attributes 'recurrent architectures' to this citation. Gehring et al. do use position embeddings and attention, so the citation is relevant to input encodings, but the descriptor 'recurrent' does not fit the cited work. Only the authors can say whether a different reference was meant or the wording should change.
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Reference or label The Fig. 9 header reads "Multiresolution hash encoding (Ours), T = 15, 133 FPS"; T is a hash table size and is written elsewhere as a power of two (e.g. 2^14 … 2^24).
- p. 8 Fig. 9 header
Multiresolution hash encoding (Ours), 𝑇 = 15, 133 FPS
Judge's note: The crop of p.8 shows 'T = 15' with no base 2 or superscript, so this is not an extraction artefact. Everywhere else in the paper T is written as 2^k. The label presumably means T = 2^15.
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Reference or label The reference list has "Convolutional Occupancy Networks" twice: Peng et al. 2020a (ECCV) and 2020b "(2020). arXiv:2003.04618 [cs.CV]"; 2020b is cited in Sec. 6 for the generative setting.
- p. 13 References
2020b. Convolutional Occupancy Networks. (2020). arXiv:2003.04618 [cs.CV]
- p. 11 Discussion, Generative setting
typically a CNN such as StyleGAN [Chan et al. 2021; DeVries et al. 2021; Peng et al. 2020b]
- p. 11 Section 6, Generative setting
[Chan et al. 2021; DeVries et al. 2021; Peng et al. 2020b]
- p. 13 Reference list
2020b. Convolutional Occupancy Networks. (2020). arXiv:2003.04618
Judge's note: The p.13 crop shows both entries with identical authors and title. This is a duplicate entry. Citing it among CNN-populated feature-grid works is a loose fit rather than clearly wrong, since ConvONet fills a feature grid with a CNN. The defect is mainly the duplication; the citation could be merged into 2020a.
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Reference or label Lehmer 1951 reference gives "Harvard University Press, Cambridge, United Kingdom, 141–146."
- p. 12 References, Lehmer 1951
Harvard University Press, Cambridge, United Kingdom
- p. 12 Reference list, Lehmer 1951
Harvard University Press, Cambridge, United Kingdom, 141–146.
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: Harvard University Press is located in Cambridge, Massachusetts, USA. The crop confirms the printed text.
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Wording Fig. 1 caption says the method uses the same hyperparameters across tasks and "only vary the hash table size". The Introduction ("configured by just two values—the number of parameters T and the desired finest resolution Nmax") and the Table 1 caption ("Only the hash table size T and max. resolution Nmax need to be tuned to the task") say Nmax is also set per task.
- p. 1 Fig. 1 caption
hyperparameters across all tasks and only vary the hash table size
- p. 2 Introduction
configured by just two values—the number of parameters 𝑇and the desired finest resolution 𝑁max
- p. 4 Table 1 caption
Only the hash table size𝑇and max. resolution 𝑁max need to be tuned to the task.
Judge's note: Checked the Fig. 1 caption, the Introduction and Table 1; Section 4 also sets Nmax per task. Nmax is set by a rule (2048 × scene size, half the image width, 2^19), so it is arguably not tuned. Even so, the caption's "only" conflicts with Table 1's own wording.
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Wording The Introduction calls T "the number of parameters T". Table 1 and Section 3 define T as the maximum entries per level (hash table size), with the parameter count bounded by "T · L · F which in our case is always T · 16 · 2".
- p. 2 Introduction, third paragraph
the number of parameters 𝑇
- p. 4 Section 3
bounded by 𝑇· 𝐿· 𝐹which in our case is always 𝑇· 16 · 2
Judge's note: This is loose shorthand rather than an outright error, since the parameter count scales with T. It is still inconsistent with the formal definition.
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Wording Section 2 says the hash encoding's quality is comparable to the dense grid encoding "despite having 20× fewer parameters", but no pair of Fig. 2 parameter counts gives 20×.
- p. 3 Section 2, Sparse parametric encodings, last paragraph
despite having 20× fewer parameters
- p. 3 Fig. 2 labels
10 k + 494 k
- p. 3 Fig. 2 labels (d) and (e)
10 k + 16.3 M
Only the authors can say what is right here.
Judge's note: Fig. 2 (p.3) counts: (c) 10 k + 33.6 M, (d) 10 k + 16.3 M, (e) 10 k + 494 k, (f) 10 k + 12.6 M. The sentence compares with the multiresolution grid (d). Against (d), (e) has about 32–33× fewer parameters and (f) about 1.3× fewer. Against (c), the ratios are about 67× and 2.7×. The 20× matches no printed pair. It may be a loose lower bound, but the paper does not say which configurations it refers to.
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Wording Table 1 lists "ranges in our results" for T as "2^14 to 2^24", but the Fig. 6 caption reports a model with "hash table sizes T of 2^12".
- p. 4 Table 1
Max. entries per level (hash table size)
- p. 7 Fig. 6 caption
With hash table sizes 𝑇 of 2
Judge's note: Table 1 and the Fig. 6 caption checked in the images. The stated range does not cover the 2^12 result.
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Wording The stated cache condition "2 · T · F > 6 · 2^20" with F = 2 is first met at T = 2^21, whereas the text puts the performance drop just beyond T ≤ 2^19 and attributes it to individual levels.
- p. 6 Section 4, Performance considerations
2 · 𝑇 · 𝐹 > 6 · 2
Only the authors can say what is right here.
Judge's note: With F = 2 the inequality holds only for T > 1.5·2^20. Several levels being resident in cache at once could explain the drop, but the text says "individual levels". The authors should clarify.
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Wording Sec. 5.2 says NGLOD is compared with hash encoding "at roughly equal parameter count", but Fig. 7 lists NGLOD at 22.3 M, 16.0 M, 11.1 M and 24.2 M against 12.2 M for hash.
- p. 7 Section 5.2
at roughly equal parameter count
- p. 8 Fig. 7 labels
22.3 M (params)
Judge's note: I read the Fig. 7 labels on the p.8 image. Two NGLOD models have about 1.8× and 2.0× the hash parameter count. NGLOD's size depends on the octree for each shape, so the counts cannot be matched exactly. 'Roughly equal' is loose wording for up to a factor of 2.
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Wording "the first 16 coefficients of the spherical harmonics basis (i.e. up to degree 4)": 16 coefficients correspond to degrees 0–3. Degree 4 would bring the total to 25.
- p. 9 Section 5.4, Model Architecture
spherical harmonics basis (i.e. up to degree 4)
Judge's note: "Degree 4" may be meant as four bands, so the wording is ambiguous rather than clearly wrong.
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Typo Introduction, para 2: "The important commonality of the these approaches" has a doubled determiner.
- p. 2 Introduction, paragraph 2
The important commonality of the these approaches
- p. 2
The important commonality of the these approaches is an encod-
Judge's note: The p.2 image shows 'of the these approaches'. It should read 'of these approaches'.
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Typo "as well a a batch size" should read "as well as a batch size".
- p. 6 Section 4, Training
as well a a batch size
Judge's note: Visible in the page image.
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Typo "𝜖 = 10−15, The choice of 𝛽1 and 𝛽2": a comma ends the sentence where a full stop is needed.
- p. 6 Section 4, Training
𝜖 = 10−15, The choice
- p. 6 Section 4, Training
𝜖 = 10−15, The choice of 𝛽1 and 𝛽2 makes
Judge's note: Checked page 6. The comma is followed by a capitalised "The".
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Typo Fig. 10 caption: "number of neurons the hidden layers" is missing "in".
- p. 9 Fig. 10 caption
number of neurons the hidden layers of the density and color MLPs
Judge's note: Visible in the crop.
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Typo "the peak signal to noise ratio (PSNR) our NeRF implementation" is missing "of".
- p. 10 Section 5.4, Comparison with high-quality offline NeRF
the peak signal to noise ratio (PSNR) our NeRF implementation
Judge's note: Visible in the crop.
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Typo Kingma & Ba reference: "arXiv:1412.6980 (June 2014)"; the identifier prefix 1412 indicates December 2014.
- p. 12 References, Kingma and Ba
arXiv:1412.6980 (June 2014)
- p. 12 Reference list
arXiv:1412.6980 (June 2014).
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: arXiv identifier 1412 denotes a December 2014 submission. The crop confirms the printed text.
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Typo Micikevicius et al. reference: "arXiv:1710.03740 (Oct. 2018)"; the identifier prefix 1710 indicates October 2017.
- p. 12 References, Micikevicius et al.
arXiv:1710.03740 (Oct. 2018)
- p. 12 Reference list
arXiv:1710.03740 (Oct. 2018).
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: arXiv identifier 1710 denotes October 2017. The entry's year 2018 may reflect a later version, but the month and year do not fit together. The crop confirms the printed text.
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Typo Page ranges in the references are printed with malformed doubled dashes: "1243—-1252", "191––205", "165—-172", "1—-11".
- p. 12 References (Gehring, Hadadan, Jansen, Nooruddin entries)
1243—-1252
- p. 12 References (Nooruddin and Turk)
191––205
Judge's note: The doubled dashes are visible in the page image, so this is not an extraction artefact. It is cosmetic.
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Typo Month abbreviations in some references are lowercase ("(nov 2013)", "(apr 2003)", "(dec 2018)"), while other entries use "Nov." and "Dec.".
- p. 12 References, Nießner et al. and Nooruddin and Turk
Article 169 (nov 2013)
- p. 12 References, Nooruddin and Turk
(apr 2003)
Judge's note: Seen in the page image. This is a house-style inconsistency only.
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Typo Pharr et al. reference repeats the edition: "From Theory to Implementation (3rd ed.) (3rd ed.)".
- p. 13 References, Pharr et al. 2016
(3rd ed.) (3rd ed.)
- p. 13 Reference list
From Theory to Implementation (3rd ed.) (3rd ed.)
Judge's note: Visible in the page image: once in the italic title and again as a separate edition field.
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Typo Misspelling in Appendix E.1: "non-linear step size as benefitial" should read "beneficial".
- p. 14 Appendix E.1, Related work
non-linear step size as benefitial
Judge's note: Seen in the crop of page 14.
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