filter low opacities when exporting

nerfstudio/scripts/exporter.py

@@ -609,9 +609,17 @@ def main(self) -> None:
             n_after = np.sum(select)
             if n_after < n_before:
                 CONSOLE.print(f"{n_before - n_after} NaN/Inf elements in {k}")
+        nan_count = np.sum(select) - n
+
+        # filter gaussians that have opacities < 1/255, because they are skipped in cuda rasterization
+        low_opacity_gaussians = (map_to_tensors["opacity"]).squeeze(axis=-1) < -5.5373  # logit(1/255)
+        lowopa_count = np.sum(low_opacity_gaussians)
+        select[low_opacity_gaussians] = 0
 
         if np.sum(select) < n:
-            CONSOLE.print(f"values have NaN/Inf in map_to_tensors, only export {np.sum(select)}/{n}")
+            CONSOLE.print(
+                f"{nan_count} Gaussians have NaN/Inf and {lowopa_count} have low opacity, only export {np.sum(select)}/{n}"
+            )
             for k, t in map_to_tensors.items():
                 map_to_tensors[k] = map_to_tensors[k][select]
             count = np.sum(select)