ZoomSplat: Rethinking Multi-view Frequency Bounds for Anti-aliased Feed-forward 3D Gaussian Splatting

Feed-forward 3D Gaussian Splatting (FF-3DGS) enables efficient sparse-view reconstruction and novel view synthesis, but these reconstructions can exhibit severe erosion and grid-like artifacts when rendered beyond the context-image sampling rates such as zoom-in operation. We propose ZoomSplat for FF-3DGS with detail-preserving reconstruction and smooth higher-resolution rendering from a fixed Gaussian representation. Although FF-3DGS models combine information from multiple input views, existing multi-view 3D frequency constraint governed by the largest sampling rate of individual views does not account for their combined observations and can impose excessive smoothing. To address this, our ZoomSplat integrates multiview-aware 3D filtering into Gaussian prediction for the first time, through an aggregated multiview frequency bound that permits finer Gaussian scales in regions supported by multiple observations. Explicit filter-size conditioning then enables the FF-3DGS models to account explicitly for the resulting filter sizes. Finally, an Opaque Scene Prior (OSP) combines termination-conditioned color normalization with transmittance regularization to compensate for residual transparency and to encourage opaque coverage. On DL3DV with six context views, ZoomSplat improves average 1.4dB PSNR across $1\times$, $2\times$, $4\times$, and $8\times$ rendering scales over TokenGS that is the second best FF-3DGS model and lifts average 3.2dB PSNR over the baseline of DepthSplat.