Index: trunk/src/tmcsim/interfaces/CADViewer.java
===================================================================
--- trunk/src/tmcsim/interfaces/CADViewer.java	(revision 44)
+++ trunk/src/tmcsim/interfaces/CADViewer.java	(revision 44)
@@ -0,0 +1,15 @@
+package tmcsim.interfaces;
+
+/**
+ * CADViewer specifies the behavior for classes that want to be Observers of the
+ * CADSimulator.
+ *
+ * @author jdalbey
+ */
+public interface CADViewer extends java.util.Observer
+{
+
+    public void setVisible(boolean state);
+
+    public void update(java.util.Observable obs, Object obj);
+}