2D Triangle Splatting for Direct Differentiable Mesh Training
Pith reviewed 2026-05-19 08:23 UTC · model grok-4.3
The pith
2D triangle splatting replaces 3D Gaussians to produce ready-to-use meshes directly from training
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
2D Triangle Splatting replaces 3D Gaussian primitives with 2D triangle primitives. This naturally forms a discrete mesh-like structure while retaining the benefits of continuous volumetric modeling. Through the incorporation and controlled annealing of a compactness parameter, the method maintains differentiability during training while producing triangle meshes with fully opaque faces at the end of optimization without the need for additional post-processing.
What carries the argument
2D triangle primitives equipped with an annealed compactness parameter that keeps the representation differentiable during optimization and forces opaque faces at convergence
If this is right
- Visual quality remains competitive with 3D Gaussian splatting methods.
- Fully opaque triangle meshes are obtained directly at the end of optimization.
- No separate post-processing step is needed to reach a usable mesh.
- Advanced effects such as relighting and shadow rendering become more straightforward.
Where Pith is reading between the lines
- The final meshes could plug directly into conventional graphics pipelines for faster rendering.
- Real-time applications might benefit if the triangle count stays low enough after training.
- The same annealing idea could be tested on other primitive shapes to improve mesh regularity.
Load-bearing premise
Annealing a compactness parameter keeps the entire training process differentiable and forces the triangles to become fully opaque by the final step.
What would settle it
A run that ends with visible semi-transparent faces or requires separate post-processing to create a valid mesh would show the direct production claim does not hold.
Figures
read the original abstract
Differentiable rendering with 3D Gaussian primitives has emerged as a powerful method for reconstructing high-fidelity 3D scenes from multi-view images. While it offers improvements over NeRF-based methods, this representation still encounters challenges with rendering speed and advanced rendering effects, such as relighting and shadow rendering, compared to mesh-based models. In this paper, we propose 2D Triangle Splatting (2DTS), a novel method that replaces 3D Gaussian primitives with 2D triangle primitives. This representation naturally forms a discrete mesh-like structure while retaining the benefits of continuous volumetric modeling. Through the incorporation and controlled annealing of a compactness parameter, our method maintains differentiability during training while producing triangle meshes with fully opaque faces at the end of optimization without the need for additional post-processing. Experimental results demonstrate that our triangle-based representation achieves competitive visual quality with Gaussian-based methods while providing a more direct bridge to mesh-based representations. Our method bridges the gap between differentiable rendering and traditional mesh-based rendering, offering a promising solution for applications requiring renderable mesh-like reconstructions. Please visit our project page at https://gaoderender.github.io/triangle-splatting.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper proposes 2D Triangle Splatting (2DTS), replacing 3D Gaussian primitives with 2D triangle primitives for differentiable rendering from multi-view images. It introduces a compactness parameter with controlled annealing to maintain differentiability during optimization while yielding triangle meshes with fully opaque faces at convergence, without post-processing. The method claims competitive visual quality versus Gaussian splatting and a more direct bridge to traditional mesh-based representations and rendering effects such as relighting.
Significance. If the central claims are substantiated, the work would be significant for closing the gap between continuous volumetric differentiable rendering and discrete mesh pipelines. Direct production of opaque, renderable triangle meshes could enable faster inference and advanced effects unavailable in Gaussian splatting, with potential downstream utility in graphics applications requiring mesh outputs. The annealing schedule for opacity is a concrete technical contribution if shown to be stable and effective.
major comments (2)
- [Abstract and §3] Abstract and §3 (method parameterization): the claim that the approach 'produc[es] triangle meshes with fully opaque faces at the end of optimization without the need for additional post-processing' is load-bearing for the 'more direct bridge to mesh-based representations' assertion. If each 2D triangle is parameterized and optimized independently (as with Gaussians) without explicit vertex-sharing, edge connectivity, or manifold constraints during training, the final output remains an unstructured collection of separate faces. This would require post-processing to obtain a standard mesh with shared vertices, directly contradicting the no-post-processing guarantee tied to the compactness annealing.
- [§4] §4 (experiments): the abstract states 'competitive visual quality' yet supplies no quantitative metrics, PSNR/SSIM tables, ablation studies on the compactness schedule, or error analysis. Without these, the experimental support for the central claim cannot be evaluated and the comparison to Gaussian baselines remains unverified.
minor comments (2)
- [Figure captions and §3.2] Figure captions and §3.2: clarify whether the rendered output during training uses alpha blending over the 2D triangles or a different compositing rule, and show explicit before/after annealing visualizations of face opacity.
- [Notation] Notation: define the compactness parameter and its annealing schedule with an explicit equation or pseudocode so that the transition from differentiable to opaque is reproducible.
Simulated Author's Rebuttal
We thank the referee for the constructive and detailed feedback. We address each major comment below with clarifications and indicate planned revisions to improve the manuscript.
read point-by-point responses
-
Referee: [Abstract and §3] Abstract and §3 (method parameterization): the claim that the approach 'produc[es] triangle meshes with fully opaque faces at the end of optimization without the need for additional post-processing' is load-bearing for the 'more direct bridge to mesh-based representations' assertion. If each 2D triangle is parameterized and optimized independently (as with Gaussians) without explicit vertex-sharing, edge connectivity, or manifold constraints during training, the final output remains an unstructured collection of separate faces. This would require post-processing to obtain a standard mesh with shared vertices, directly contradicting the no-post-processing guarantee tied to the compactness annealing.
Authors: We appreciate the referee's careful analysis of this distinction. The 2D triangles are optimized independently without explicit vertex sharing or manifold constraints during training, similar to Gaussian primitives. The compactness annealing drives each triangle to full opacity by convergence, allowing the resulting opaque faces to be rendered directly via standard triangle rasterization without any post-processing for transparency or opacity adjustment. Our claim of 'no additional post-processing' and 'more direct bridge to mesh-based representations' specifically refers to this opacity property and the discrete triangle structure, which can be used immediately in mesh pipelines. We acknowledge that producing a single connected manifold mesh with shared vertices would require separate post-processing steps (e.g., vertex merging), which is not part of our current guarantee. We will revise the abstract and §3 to explicitly clarify this scope and avoid overstatement regarding topological connectivity. revision: yes
-
Referee: [§4] §4 (experiments): the abstract states 'competitive visual quality' yet supplies no quantitative metrics, PSNR/SSIM tables, ablation studies on the compactness schedule, or error analysis. Without these, the experimental support for the central claim cannot be evaluated and the comparison to Gaussian baselines remains unverified.
Authors: We agree that quantitative metrics are necessary to rigorously support the claim of competitive visual quality. The current manuscript emphasizes qualitative results and visual comparisons in §4. In the revision we will add PSNR/SSIM tables against Gaussian splatting baselines, ablation studies on the compactness annealing schedule, and relevant error analysis to enable direct evaluation of the experimental claims. revision: yes
Circularity Check
Derivation self-contained via new primitives and annealing schedule
full rationale
The paper defines 2D Triangle Splatting as a replacement for 3D Gaussians, using an independently introduced compactness parameter that is annealed to produce opaque faces. No load-bearing step reduces the claimed mesh output or differentiability to a fitted quantity from prior work or self-citation by construction. The bridge to mesh representations and lack of post-processing follow directly from the proposed representation and schedule rather than tautological redefinition of inputs. This is the normal case of an honest new method with independent content.
Axiom & Free-Parameter Ledger
free parameters (1)
- compactness parameter
axioms (1)
- domain assumption 2D triangle primitives naturally form a discrete mesh-like structure while retaining benefits of continuous volumetric modeling.
Lean theorems connected to this paper
-
IndisputableMonolith/Cost/FunctionalEquation.leanwashburn_uniqueness_aczel unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
opacity of the triangle on each pixel oj as: oj = O · exp(− 1/2 e2γ j), ej = 1 − 3 · min(a1 j , a2 j , a3 j )
-
IndisputableMonolith/Foundation/AlphaCoordinateFixation.leanalpha_pin_under_high_calibration unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
compactness parameter γ … gradually increasing … solid mesh representation
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
-
[1]
Barron, Ben Mildenhall, Matthew Tancik, Pe- ter Hedman, Ricardo Martin-Brualla, and Pratul P
Jonathan T. Barron, Ben Mildenhall, Matthew Tancik, Pe- ter Hedman, Ricardo Martin-Brualla, and Pratul P. Srini- vasan. Mip-NeRF: A multiscale representation for anti- aliasing neural radiance fields, 2021. 2
work page 2021
-
[2]
Barron, Ben Mildenhall, Dor Verbin, Pratul P
Jonathan T. Barron, Ben Mildenhall, Dor Verbin, Pratul P. Srinivasan, and Peter Hedman. Mip-NeRF 360: Unbounded anti-aliased neural radiance fields. CVPR, 2022. 2, 6, 7, 11, 12
work page 2022
-
[3]
PGSR: Planar-based gaussian splat- ting for efficient and high-fidelity surface reconstruction
Danpeng Chen, Hai Li, Weicai Ye, Yifan Wang, Weijian Xie, Shangjin Zhai, Nan Wang, Haomin Liu, Hujun Bao, and Guofeng Zhang. PGSR: Planar-based gaussian splat- ting for efficient and high-fidelity surface reconstruction. IEEE Transactions on Visualization and Computer Graph- ics, pages 1–12, 2024. 1, 3
work page 2024
-
[4]
Point-based multi-view stereo network
Rui Chen, Songfang Han, Jing Xu, and Hao Su. Point-based multi-view stereo network. In The IEEE International Con- ference on Computer Vision (ICCV), 2019. 2
work page 2019
-
[5]
Zhiqin Chen, Thomas Funkhouser, Peter Hedman, and An- drea Tagliasacchi. MobileNeRF: Exploiting the polygon ras- terization pipeline for efficient neural field rendering on mo- bile architectures. In The Conference on Computer Vision and Pattern Recognition (CVPR), 2023. 3
work page 2023
-
[6]
Plenoxels: Radiance fields without neural networks
Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, 2022. 5
work page 2022
-
[7]
Kaolin: A pytorch library for accelerating 3d deep learning research
Clement Fuji Tsang, Maria Shugrina, Jean Francois Lafleche, Or Perel, Charles Loop, Towaki Takikawa, Vismay Modi, Alexander Zook, Jiehan Wang, Wenzheng Chen, Tian- chang Shen, Jun Gao, Krishna Murthy Jatavallabhula, Ed- ward Smith, Artem Rozantsev, Sanja Fidler, Gavriel State, Jason Gorski, Tommy Xiang, Jianing Li, Michael Li, and Rev Lebaredian. Kaolin: ...
-
[8]
Yasutaka Furukawa and Carlos Hern ´andez. Multi-view stereo: A tutorial. Foundations and Trends® in Computer Graphics and Vision, 9(1-2):1–148, 2015. 2
work page 2015
-
[9]
Accurate, dense, and robust multiview stereopsis
Yasutaka Furukawa and Jean Ponce. Accurate, dense, and robust multiview stereopsis. IEEE Transactions on Pattern Analysis and Machine Intelligence, 32(8):1362–1376, 2010. 2
work page 2010
-
[10]
Relightable 3D Gaussians: Realistic point cloud relighting with BRDF decomposition and ray tracing
Jian Gao, Chun Gu, Youtian Lin, Zhihao Li, Hao Zhu, Xun Cao, Li Zhang, and Yao Yao. Relightable 3D Gaussians: Realistic point cloud relighting with BRDF decomposition and ray tracing. In ECCV, pages 73–89, Berlin, Heidelberg,
-
[11]
TetSphere Splatting: Representing high-quality ge- ometry with Lagrangian volumetric meshes
Minghao Guo, Bohan Wang, Kaiming He, and Wojciech Ma- tusik. TetSphere Splatting: Representing high-quality ge- ometry with Lagrangian volumetric meshes. In The Thir- teenth International Conference on Learning Representa- tions, 2025. 1, 3
work page 2025
-
[12]
GES: Generalized exponential splatting for efficient radiance field rendering
Abdullah Hamdi, Luke Melas-Kyriazi, Jinjie Mai, Guocheng Qian, Ruoshi Liu, Carl V ondrick, Bernard Ghanem, and Andrea Vedaldi. GES: Generalized exponential splatting for efficient radiance field rendering. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 19812–19822, 2024. 2, 3
work page 2024
-
[13]
Deep blending for free-viewpoint image-based rendering
Peter Hedman, Julien Philip, True Price, Jan-Michael Frahm, George Drettakis, and Gabriel Brostow. Deep blending for free-viewpoint image-based rendering. ACM Transactions on Graphics (Proc. SIGGRAPH Asia) , 37(6):257:1–257:15,
- [14]
-
[15]
3d convex splatting: Radiance field rendering with 3d smooth convexes,
Jan Held, Renaud Vandeghen, Abdullah Hamdi, Adrien Deli‘ege, Anthony Cioppa, Silvio Giancola, Andrea Vedaldi, Bernard Ghanem, and Marc Van Droogenbroeck. 3D con- vex splatting: Radiance field rendering with 3D smooth con- vexes. arXiv, abs/2411.14974, 2024. 1, 3
-
[16]
2D gaussian splatting for geometrically ac- curate radiance fields
Binbin Huang, Zehao Yu, Anpei Chen, Andreas Geiger, and Shenghua Gao. 2D gaussian splatting for geometrically ac- curate radiance fields. In SIGGRAPH 2024 Conference Pa- pers. Association for Computing Machinery, 2024. 1, 2, 3, 5, 6, 7, 8, 12, 13
work page 2024
-
[17]
Learning a multi-view stereo machine
Abhishek Kar, Christian H ¨ane, and Jitendra Malik. Learning a multi-view stereo machine. In Advances in Neural Infor- mation Processing Systems . Curran Associates, Inc., 2017. 2
work page 2017
-
[18]
3D gaussian splatting for real-time radiance field rendering
Bernhard Kerbl, Georgios Kopanas, Thomas Leimk ¨uhler, and George Drettakis. 3D gaussian splatting for real-time radiance field rendering. ACM Transactions on Graphics, 42 (4), 2023. 1, 2, 3, 6, 9, 12
work page 2023
-
[19]
Tanks and temples: Benchmarking large-scale scene reconstruction
Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: Benchmarking large-scale scene reconstruction. ACM Transactions on Graphics (ToG) , 36 (4):1–13, 2017. 6, 11, 13, 14. 6, 7, 11, 12
work page 2017
-
[20]
K.N. Kutulakos and S.M. Seitz. A theory of shape by space carving. In Proceedings of the Seventh IEEE International Conference on Computer Vision, pages 307–314 vol.1, 1999. 2
work page 1999
-
[21]
Modular primitives for high-performance differentiable rendering
Samuli Laine, Janne Hellsten, Tero Karras, Yeongho Seol, Jaakko Lehtinen, and Timo Aila. Modular primitives for high-performance differentiable rendering. ACM Transac- tions on Graphics, 39(6), 2020. 3
work page 2020
-
[22]
Matrixcity: A large-scale city dataset for city-scale neural rendering and beyond
Yixuan Li, Lihan Jiang, Linning Xu, Yuanbo Xiangli, Zhen- zhi Wang, Dahua Lin, and Bo Dai. Matrixcity: A large-scale city dataset for city-scale neural rendering and beyond. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 3205–3215, 2023. 7, 12, 13
work page 2023
-
[23]
Weikai Lin, Yu Feng, and Yuhao Zhu. MetaSapiens: Real- time neural rendering with efficiency-aware pruning and ac- celerated foveated rendering, 2024. 1
work page 2024
-
[24]
William E. Lorensen and Harvey E. Cline. Marching cubes: A high resolution 3d surface construction algorithm. SIG- GRAPH Comput. Graph., 21(4):163–169, 1987. 2
work page 1987
-
[25]
Srinivasan, Matthew Tancik, Jonathan T
Ben Mildenhall, Pratul P. Srinivasan, Matthew Tancik, Jonathan T. Barron, Ravi Ramamoorthi, and Ren Ng. NeRF: Representing scenes as neural radiance fields for view syn- thesis. In ECCV, 2020. 1, 2, 6, 7, 8, 11, 12
work page 2020
-
[26]
Extracting Triangular 3D Models, Materials, and Light- ing From Images
Jacob Munkberg, Jon Hasselgren, Tianchang Shen, Jun Gao, Wenzheng Chen, Alex Evans, Thomas M¨uller, and Sanja Fi- dler. Extracting Triangular 3D Models, Materials, and Light- ing From Images. In Proceedings of the IEEE/CVF Confer- ence on Computer Vision and Pattern Recognition (CVPR) , pages 8280–8290, 2022. 2, 3, 6, 7, 8
work page 2022
-
[27]
Newcombe, Shahram Izadi, Otmar Hilliges, David Molyneaux, David Kim, Andrew J
Richard A. Newcombe, Shahram Izadi, Otmar Hilliges, David Molyneaux, David Kim, Andrew J. Davison, Push- meet Kohi, Jamie Shotton, Steve Hodges, and Andrew Fitzgibbon. KinectFusion: Real-time dense surface mapping and tracking. In 2011 10th IEEE International Symposium on Mixed and Augmented Reality , pages 127–136, 2011. 1, 3
work page 2011
-
[28]
Sch ¨onberger, Enliang Zheng, Jan-Michael Frahm, and Marc Pollefeys
Johannes L. Sch ¨onberger, Enliang Zheng, Jan-Michael Frahm, and Marc Pollefeys. Pixelwise view selection for unstructured multi-view stereo. In Computer Vision – ECCV 2016, pages 501–518, Cham, 2016. Springer International Publishing. 1, 2
work page 2016
-
[29]
Deep marching tetrahedra: a hybrid represen- tation for high-resolution 3d shape synthesis
Tianchang Shen, Jun Gao, Kangxue Yin, Ming-Yu Liu, and Sanja Fidler. Deep marching tetrahedra: a hybrid represen- tation for high-resolution 3d shape synthesis. In Advances in Neural Information Processing Systems (NeurIPS), 2021. 3
work page 2021
-
[30]
Flexible isosurface extraction for gradient-based mesh optimization
Tianchang Shen, Jacob Munkberg, Jon Hasselgren, Kangxue Yin, Zian Wang, Wenzheng Chen, Zan Gojcic, Sanja Fidler, Nicholas Sharp, and Jun Gao. Flexible isosurface extraction for gradient-based mesh optimization. ACM Trans. Graph., 42(4), 2023. 3
work page 2023
-
[31]
MeshSplats: Mesh-based rendering with gaussian splatting initialization,
Rafał Tobiasz, Grzegorz Wilczy ´nski, Marcin Mazur, Sławomir Tadeja, and Przemysław Spurek. MeshSplats: Mesh-based rendering with gaussian splatting initialization,
-
[32]
Mvsnet: Depth inference for unstructured multi-view stereo
Yao Yao, Zixin Luo, Shiwei Li, Tian Fang, and Long Quan. Mvsnet: Depth inference for unstructured multi-view stereo. European Conference on Computer Vision (ECCV), 2018. 2
work page 2018
-
[33]
GSDF: 3DGS meets SDF for improved neural rendering and reconstruction
Mulin Yu, Tao Lu, Linning Xu, Lihan Jiang, Yuanbo Xiangli, and Bo Dai. GSDF: 3DGS meets SDF for improved neural rendering and reconstruction. In Advances in Neural Infor- mation Processing Systems , pages 129507–129530. Curran Associates, Inc., 2024. 3
work page 2024
-
[34]
Mip-Splatting: Alias-free 3D gaus- sian splatting
Zehao Yu, Anpei Chen, Binbin Huang, Torsten Sattler, and Andreas Geiger. Mip-Splatting: Alias-free 3D gaus- sian splatting. Conference on Computer Vision and Pattern Recognition (CVPR), 2024. 2
work page 2024
-
[35]
RaDe-GS: Rasterizing depth in gaussian splatting, 2024
Baowen Zhang, Chuan Fang, Rakesh Shrestha, Yixun Liang, Xiaoxiao Long, and Ping Tan. RaDe-GS: Rasterizing depth in gaussian splatting, 2024. 1, 3
work page 2024
-
[36]
Neu- ral signed distance function inference through splatting 3d gaussians pulled on zero-level set
Wenyuan Zhang, Yu-Shen Liu, and Zhizhong Han. Neu- ral signed distance function inference through splatting 3d gaussians pulled on zero-level set. In Advances in Neural Information Processing Systems, 2024. 3
work page 2024
-
[37]
Open3D: A Modern Library for 3D Data Processing
Qian-Yi Zhou, Jaesik Park, and Vladlen Koltun. Open3D: A modern library for 3D data processing. arXiv:1801.09847,
work page internal anchor Pith review Pith/arXiv arXiv
-
[38]
M. Zwicker, H. Pfister, J. van Baar, and M. Gross. Ewa vol- ume splatting. In Proceedings Visualization, 2001. VIS ’01., pages 29–538, 2001. 3 A. Detailed Proof of Equations A.1. Render Normal from Depth Given a rendered depth image dj, we can infer a camera space normal image n′ j as follows. We first define: Dj = [Dx, Dy] |Pj = 1 d ∂d ∂x , 1 d ∂d ∂y |Pj...
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.