ExMesh++: From Multi-View Images to Relightable UV-PBR Mesh Assets via Topology-Adaptive Reconstruction and Decomposition

Chuanjin Fan Lifan Wu Wenjie Chang Hanzhi Chang Wenfei Yang Tianzhu Zhang

University of Science and Technology of China · Alibaba Group, Amap

Paper Watch video
ExMesh++ topology-adaptive optimization, exported UV-PBR asset maps, and relighting results.
ExMesh++ progressively refines an explicit mesh, exports standard UV-PBR maps, and renders the same asset under novel environment illumination.

01 · Overview

  1. 01

    Topology-adaptive explicit reconstruction

    Mesh geometry and topology are directly optimized through vertex splitting and merging, with consistent UV updates during topology changes.

  2. 02

    UV-PBR decomposition on a stable carrier

    The reconstructed mesh and UV coordinates are frozen before optimizing explicit PBR maps and environment lighting, reducing compensation among geometry, materials, and illumination.

  3. 03

    Shared materials for indirect illumination

    One-bounce diffuse indirect lighting traces secondary rays and queries the same UV-PBR maps, without introducing a learned residual appearance field.

  4. 04

    Exportable assets for standard workflows

    The resulting compact mesh and material maps can be directly relit and edited in standard graphics tools.

ExMesh++ extends our previous ExMesh framework from explicit mesh reconstruction to complete relightable asset reconstruction. Visit the ExMesh project page

02 · Video

03 · Interactive Results

Rotate the asset. Change the light.

Explore the exported UV-PBR assets in real time while geometry and materials remain fixed and only the environment illumination changes. This browser preview uses direct environment lighting only and does not include the one-bounce indirect illumination used by our offline renderer.

Object

Real-time UV-PBR preview

Preparing the interactive viewer…

Drag to rotate · Scroll or pinch to zoom

Lighting

04 · Method

Two-stage ExMesh++ method: topology-adaptive UV mesh reconstruction followed by UV-PBR asset decomposition with direct and indirect illumination.
Stage I

Topology-adaptive UV mesh reconstruction

Vertex splitting and merging refine explicit geometry and connectivity while local updates keep the UV parameterization valid.

Stage II

UV-PBR asset decomposition

The mesh-UV carrier is frozen while shared material maps and environment lighting are optimized for direct and one-bounce illumination.

05 · Results

Material-light decomposition

On Synthetic4Relight, ExMesh++ recovers cleaner albedo, roughness, and environment lighting while preserving convincing appearance under novel illumination.

Qualitative comparison of relighting, albedo, roughness, and recovered environment maps on Synthetic4Relight.
Relight · Albedo · Roughness · Environment map

Indirect illumination

Secondary-ray tracing queries the same shared UV-PBR materials, producing smoother, illumination-dependent indirect components around occlusions and nearby surfaces.

Relighting comparison under fireplace, forest, night, and snow environment maps with indirect-light component insets.
Training illumination and four novel environments

06 · Citation

Build on ExMesh++.

If you find this work useful, please cite our paper.

BibTeX 
@article{fan2026exmeshpp,
  title   = {ExMesh++: From Multi-View Images to Relightable
             UV-PBR Mesh Assets via Topology-Adaptive
             Reconstruction and Decomposition},
  author  = {Fan, Chuanjin and Wu, Lifan and Chang, Wenjie and
             Chang, Hanzhi and Yang, Wenfei and Zhang, Tianzhu},
  journal = {arXiv preprint arXiv:2608.24109},
  year    = {2026}
}