SceneContraction maps to range [-2, 2], not [-1, 1]. (#1872)

nerfstudio/field_components/spatial_distortions.py

@@ -51,7 +51,7 @@ class SceneContraction(SpatialDistortion):
             \\end{cases}
 
         If the order is not specified, we use the Frobenius norm, this will contract the space to a sphere of
-        radius 1. If the order is L_inf (order=float("inf")), we will contract the space to a cube of side length 2.
+        radius 2. If the order is L_inf (order=float("inf")), we will contract the space to a cube of side length 4.
         If using voxel based encodings such as the Hash encoder, we recommend using the L_inf norm.
 
         Args:

nerfstudio/fields/sdf_field.py

@@ -257,8 +257,8 @@ class SDFField(Field):
         """forward the geonetwork"""
         if self.use_grid_feature:
             positions = self.spatial_distortion(inputs)
-
-            positions = (positions + 1.0) / 2.0
+            # map range [-2, 2] to [0, 1]
+            positions = (positions + 2.0) / 4.0
             feature = self.encoding(positions)
         else:
             feature = torch.zeros_like(inputs[:, :1].repeat(1, self.encoding.n_output_dims))