update documenation in geometry.py.

1 files changed, 13 insertions, 3 deletions

diff --git a/geometry.py b/geometry.py
index cccf516..1b1f004 100644
--- a/geometry.py
+++ b/geometry.py
@@ -12,6 +12,7 @@ import gzip
 standard_wavelengths = np.arange(200, 810, 20).astype(np.float32)
 
 class Mesh(object):
+    "Triangle mesh object."
     def __init__(self, vertices, triangles, remove_duplicate_vertices=False):
         vertices = np.asarray(vertices, dtype=np.float32)
         triangles = np.asarray(triangles, dtype=np.int32)
@@ -74,6 +75,8 @@ class Mesh(object):
         return Mesh(np.concatenate((self.vertices, other.vertices)), np.concatenate((self.triangles, other.triangles + len(self.vertices))))
 
 class Solid(object):
+    """Solid object attaches materials, surfaces, and colors to each triangle
+    in a Mesh object."""
     def __init__(self, mesh, material1=None, material2=None, surface=None, color=0xffffff):
         self.mesh = mesh
 
@@ -194,27 +197,34 @@ def morton_order(mesh, bits):
     return interleave(mean_positions, bits)
 
 class Geometry(object):
+    "Geometry object."
     def __init__(self, detector_material=None):
         self.detector_material = detector_material
         self.solids = []
         self.solid_rotations = []
         self.solid_displacements = []
 
-    def add_solid(self, solid, rotation=np.identity(3), displacement=(0,0,0)):
+    def add_solid(self, solid, rotation=None, displacement=None):
         """
         Add the solid `solid` to the geometry. When building the final triangle
         mesh, `solid` will be placed by rotating it with the rotation matrix
         `rotation` and displacing it by the vector `displacement`.
         """
 
-        rotation = np.asarray(rotation, dtype=np.float32)
+        if rotation is None:
+            rotation = np.identity(3)
+        else:
+            rotation = np.asarray(rotation, dtype=np.float32)
 
         if rotation.shape != (3,3):
             raise ValueError('rotation matrix has the wrong shape.')
 
         self.solid_rotations.append(rotation.astype(np.float32))
 
-        displacement = np.asarray(displacement, dtype=np.float32)
+        if displacement is None:
+            displacement = np.zeros(3)
+        else:
+            displacement = np.asarray(displacement, dtype=np.float32)
 
         if displacement.shape != (3,):
             raise ValueError('displacement vector has the wrong shape.')