From 96be9b22b8d538ef5fa445837482be5c6626ffb7 Mon Sep 17 00:00:00 2001
From: Aditya kharmale <134163659+AdityaKharmaleGoat7@users.noreply.github.com>
Date: Fri, 9 Oct 2026 16:31:53 +0900
Subject: [PATCH] Make pymeshlab imports lazy in exporter utilities

---
 nerfstudio/exporter/exporter_utils.py |  4 +++-
 nerfstudio/exporter/tsdf_utils.py     |  5 +++--
 tests/test_exporter_imports.py        | 21 +++++++++++++++++++++
 3 files changed, 27 insertions(+), 3 deletions(-)
 create mode 100644 tests/test_exporter_imports.py

diff --git a/nerfstudio/exporter/exporter_utils.py b/nerfstudio/exporter/exporter_utils.py
index 3cd1fc2872..21ac101ad7 100644
--- a/nerfstudio/exporter/exporter_utils.py
+++ b/nerfstudio/exporter/exporter_utils.py
@@ -23,7 +23,6 @@
 from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple
 
 import numpy as np
-import pymeshlab
 import torch
 from jaxtyping import Float
 from rich.progress import BarColumn, Progress, TaskProgressColumn, TextColumn, TimeRemainingColumn
@@ -41,6 +40,7 @@
     # Importing open3d can take ~1 second, so only do it below if we actually
     # need it.
     import open3d as o3d
+    import pymeshlab
 
 
 @dataclass
@@ -71,6 +71,8 @@ def get_mesh_from_pymeshlab_mesh(mesh: pymeshlab.Mesh) -> Mesh:  # type: ignore
 
 def get_mesh_from_filename(filename: str, target_num_faces: Optional[int] = None) -> Mesh:
     """Get a Mesh from a filename."""
+    import pymeshlab
+
     ms = pymeshlab.MeshSet()  # type: ignore
     ms.load_new_mesh(filename)
     if target_num_faces is not None:
diff --git a/nerfstudio/exporter/tsdf_utils.py b/nerfstudio/exporter/tsdf_utils.py
index f3f1e53571..427bea964c 100644
--- a/nerfstudio/exporter/tsdf_utils.py
+++ b/nerfstudio/exporter/tsdf_utils.py
@@ -23,7 +23,6 @@
 from typing import List, Optional, Tuple, Union
 
 import numpy as np
-import pymeshlab
 import torch
 import torch.nn.functional as F
 from jaxtyping import Bool, Float
@@ -50,7 +49,7 @@ class TSDF:
     weights: Float[Tensor, "xdim ydim zdim"]
     """TSDF weights for each voxel."""
     colors: Float[Tensor, "xdim ydim zdim 3"]
-    """TSDF colors for each voxel."""
+    """TSDF colors of each voxel."""
     voxel_size: Float[Tensor, "3"]
     """Size of each voxel in the TSDF. [x, y, z] size."""
     origin: Float[Tensor, "3"]
@@ -147,6 +146,8 @@ def export_mesh(cls, mesh: Mesh, filename: str) -> None:
             mesh: The mesh to export.
             filename: The filename to export the mesh to.
         """
+        import pymeshlab
+
         assert mesh.colors is not None
         vertex_matrix = mesh.vertices.cpu().numpy().astype("float64")
         face_matrix = mesh.faces.cpu().numpy().astype("int32")
diff --git a/tests/test_exporter_imports.py b/tests/test_exporter_imports.py
new file mode 100644
index 0000000000..9174f95cfc
--- /dev/null
+++ b/tests/test_exporter_imports.py
@@ -0,0 +1,21 @@
+"""Tests for exporter dependency imports."""
+
+import importlib
+import sys
+
+
+def test_exporter_modules_do_not_eagerly_import_pymeshlab(monkeypatch):
+    """Exporter modules should import without initializing pymeshlab."""
+    monkeypatch.setitem(sys.modules, "pymeshlab", None)
+
+    modules = [
+        "nerfstudio.exporter.exporter_utils",
+        "nerfstudio.exporter.tsdf_utils",
+    ]
+    for module in modules:
+        sys.modules.pop(module, None)
+
+    for module in modules:
+        importlib.import_module(module)
+
+    assert sys.modules["pymeshlab"] is None