Hexelate: Compact Surface Primitives for Efficient Scene Rendering and Reconstruction

Novel view synthesis and 3D reconstruction have advanced rapidly with radiance fields and splatting, yet their memory and computational demands limit their use in resource-constrained settings. We introduce Hexels, planar hexagonal surface elements with a first-order spatial color field for efficient 3D scene and 2D image representation. Hexels exploit locally planar regions with smoothly varying appearance using fewer, larger primitives. Their hexagonal support provides an area and boundary-efficient domain, while the local color field captures appearance variation within each primitive.Across 34 scenes, compact fixed-population Hexels improve PSNR over memory-matched 2DGS by 4.53–7.38 dB across dataset subsets. With densification and view-dependent appearance, Hexels improve PSNR over unconstrained 2DGS by 0.89 dB on DTU and 0.88 dB on Tanks and Temples. On Mip-NeRF360, they are 0.33 dB below 2DGS while rendering at $2.06\times$ its speed with 83.9% less deployment storage. For all-view DTU surface reconstruction, fixed-population Hexels achieve 0.978 mm Chamfer distance, reducing error by 28.9% relative to memory-matched 2DGS, although unconstrained 2DGS remains more accurate. The same primitive also improves 2D image representation over Image-GS.