diff --git a/docs/source/usersguide/input.rst b/docs/source/usersguide/input.rst
index d7245bc6e1..f7e70ef209 100644
--- a/docs/source/usersguide/input.rst
+++ b/docs/source/usersguide/input.rst
@@ -1092,7 +1092,7 @@ The ``<tally>`` element accepts the following sub-elements:
       all of the harmonic moments of order 0 to N.  N must be between 0 and 10.
 
     :total-YN:
-      The total reaction rate expanded via spherical harmonics about the 
+      The total reaction rate expanded via spherical harmonics about the
       direction of motion of the neutron, :math:`\Omega`.
       This score will tally all of the harmonic moments of order 0 to N.  N must
       be between 0 and 10.
@@ -1229,7 +1229,7 @@ sub-elements:
 attribute or sub-element:
 
   :pixels:
-    Specifies the number of pixes or voxels to be used along each of the basis
+    Specifies the number of pixels or voxels to be used along each of the basis
     directions for "slice" and "voxel" plots, respectively. Should be two or
     three integers separated by spaces.
 
@@ -1321,11 +1321,11 @@ attributes or sub-elements.  These are not used in "voxel" plots:
       boundaries. Specifying this as 0 indicates that lines will be 1 pixel
       thick, specifying 1 indicates 3 pixels thick, specifying 2 indicates
       5 pixels thick, etc.
-    
+
     :color:
       Specifies the custom color for the meshlines boundaries. Should be 3
       integers separated by whitespace.  This element is optional.
-    
+
       *Default*: 0 0 0 (black)
 
     *Default*: None
diff --git a/src/relaxng/plots.rnc b/src/relaxng/plots.rnc
index a7c657864d..27b2ae7f72 100644
--- a/src/relaxng/plots.rnc
+++ b/src/relaxng/plots.rnc
@@ -3,28 +3,29 @@ element plots {
     (element id { xsd:int } | attribute id { xsd:int })? &
     (element filename { xsd:string { maxLength = "50" } } |
       attribute filename { xsd:string { maxLength = "50" } })? &
-    (element type { "slice" } | attribute type { "slice" })? &
+    (element type { "slice" | "voxel" } |
+      attribute type { "slice" | "voxel" })? &
     (element color { ( "cell" | "mat" | "material" ) } |
       attribute color { ( "cell" | "mat" | "material" ) })? &
-    (element origin { list { xsd:double+ } } | 
+    (element origin { list { xsd:double+ } } |
       attribute origin { list { xsd:double+ } })? &
-    (element width { list { xsd:double+ } } | 
+    (element width { list { xsd:double+ } } |
       attribute width { list { xsd:double+ } })? &
     (element basis { ( "xy" | "yz" | "xz" ) } |
       attribute basis { ( "xy" | "yz" | "xz" ) })? &
-    (element pixels { list { xsd:int+ } } | 
+    (element pixels { list { xsd:int+ } } |
       attribute pixels { list { xsd:int+ } })? &
     (element background { list { xsd:int+ } } |
       attribute background { list { xsd:int+ } })? &
     element col_spec {
       (element id { xsd:int } | attribute id { xsd:int }) &
-      (element rgb { list { xsd:int+ } } | 
+      (element rgb { list { xsd:int+ } } |
         attribute rgb { list { xsd:int+ } })
     }* &
     element mask {
-      (element components { list { xsd:int+ } } | 
+      (element components { list { xsd:int+ } } |
         attribute components { list { xsd:int+ } }) &
-      (element background { list { xsd:int+ } } | 
+      (element background { list { xsd:int+ } } |
         attribute background { list { xsd:int+ } })
     }* &
     element meshlines {
@@ -32,7 +33,7 @@ element plots {
         attribute meshtype { ( "tally" | "entropy" | "ufs" | "cmfd" ) }) &
       (element id { xsd:int } | attribute id { xsd:int })? &
       (element linewidth { xsd:int } | attribute linewidth { xsd:int }) &
-      (element color { list { xsd:int+ } } | 
+      (element color { list { xsd:int+ } } |
         attribute color { list { xsd:int+ } })?
     }*
   }*