diff --git a/gprMax/geometry_outputs.py b/gprMax/geometry_outputs.py
index c2efc83c..2da25a9f 100644
--- a/gprMax/geometry_outputs.py
+++ b/gprMax/geometry_outputs.py
@@ -335,9 +335,9 @@ class GeometryObjects(object):
         self.materialsfilename = basefilename + '_materials.txt'
 
         # Sizes of arrays to write necessary to update progress bar
-        self.solidsize = (self.nx + 1) * (self.ny + 1) * (self.nz + 1) * np.dtype(np.int16).itemsize
-        self.rigidsize = 18 * (self.nx + 1) * (self.ny + 1) * (self.nz + 1) * np.dtype(np.int8).itemsize
-        self.IDsize = 6 * (self.nx + 1) * (self.ny + 1) * (self.nz + 1) * np.dtype(np.uint32).itemsize
+        self.solidsize = self.nx * self.ny * self.nz * np.dtype(np.int16).itemsize
+        self.rigidsize = 18 * self.nx * self.ny * self.nz * np.dtype(np.int8).itemsize
+        self.IDsize = 6 * self.nx * self.ny * self.nz * np.dtype(np.uint32).itemsize
         self.datawritesize = self.solidsize + self.rigidsize + self.IDsize
 
     def write_hdf5(self, G, pbar):
@@ -355,14 +355,14 @@ class GeometryObjects(object):
         fdata.attrs['dx_dy_dz'] = (G.dx, G.dy, G.dz)
 
         # Get minimum and maximum integers of materials in geometry objects volume
-        minmat = np.amin(G.ID[:, self.xs:self.xf + 1, self.ys:self.yf + 1, self.zs:self.zf + 1])
-        maxmat = np.amax(G.ID[:, self.xs:self.xf + 1, self.ys:self.yf + 1, self.zs:self.zf + 1])
-        fdata['/data'] = G.solid[self.xs:self.xf + 1, self.ys:self.yf + 1, self.zs:self.zf + 1].astype('int16') - minmat
+        minmat = np.amin(G.ID[:, self.xs:self.xf, self.ys:self.yf, self.zs:self.zf])
+        maxmat = np.amax(G.ID[:, self.xs:self.xf, self.ys:self.yf, self.zs:self.zf])
+        fdata['/data'] = G.solid[self.xs:self.xf, self.ys:self.yf, self.zs:self.zf].astype('int16') - minmat
         pbar.update(self.solidsize)
-        fdata['/rigidE'] = G.rigidE[:, self.xs:self.xf + 1, self.ys:self.yf + 1, self.zs:self.zf + 1]
-        fdata['/rigidH'] = G.rigidH[:, self.xs:self.xf + 1, self.ys:self.yf + 1, self.zs:self.zf + 1]
+        fdata['/rigidE'] = G.rigidE[:, self.xs:self.xf, self.ys:self.yf, self.zs:self.zf]
+        fdata['/rigidH'] = G.rigidH[:, self.xs:self.xf, self.ys:self.yf, self.zs:self.zf]
         pbar.update(self.rigidsize)
-        fdata['/ID'] = G.ID[:, self.xs:self.xf + 1, self.ys:self.yf + 1, self.zs:self.zf + 1] - minmat
+        fdata['/ID'] = G.ID[:, self.xs:self.xf, self.ys:self.yf, self.zs:self.zf] - minmat
         pbar.update(self.IDsize)
 
         # Write materials list to a text file