diff --git a/src/java/com/threerings/media/tile/bundle/tools/TileSetBundler.java b/src/java/com/threerings/media/tile/bundle/tools/TileSetBundler.java
index 19667b484..0b5dadaa5 100644
--- a/src/java/com/threerings/media/tile/bundle/tools/TileSetBundler.java
+++ b/src/java/com/threerings/media/tile/bundle/tools/TileSetBundler.java
@@ -1,5 +1,5 @@
 //
-// $Id: TileSetBundler.java,v 1.2 2001/11/29 00:13:20 mdb Exp $
+// $Id: TileSetBundler.java,v 1.3 2001/11/29 21:58:15 mdb Exp $
 
 package com.threerings.media.tools.tile.bundle;
 
@@ -30,7 +30,7 @@ import com.samskivert.io.PersistenceException;
 import com.threerings.media.Log;
 import com.threerings.media.tile.TileSet;
 import com.threerings.media.tile.TileSetIDBroker;
-import com.threerings.media.tile.bundle.BundledTileSetRepository;
+import com.threerings.media.tile.bundle.BundleUtil;
 import com.threerings.media.tile.bundle.TileSetBundle;
 import com.threerings.media.tools.tile.xml.TileSetRuleSet;
 
@@ -270,8 +270,7 @@ public class TileSetBundler
         try {
             // first write a serialized representation of the tileset
             // bundle object to the bundle jar file
-            JarEntry entry = new JarEntry(
-                BundledTileSetRepository.METADATA_PATH);
+            JarEntry entry = new JarEntry(BundleUtil.METADATA_PATH);
             jar.putNextEntry(entry);
             ObjectOutputStream oout = new ObjectOutputStream(jar);
             oout.writeObject(bundle);
diff --git a/src/java/com/threerings/media/tile/tools/xml/ObjectTileSetRuleSet.java b/src/java/com/threerings/media/tile/tools/xml/ObjectTileSetRuleSet.java
new file mode 100644
index 000000000..02ca9c1c9
--- /dev/null
+++ b/src/java/com/threerings/media/tile/tools/xml/ObjectTileSetRuleSet.java
@@ -0,0 +1,75 @@
+//
+// $Id: ObjectTileSetRuleSet.java,v 1.1 2001/11/29 21:58:15 mdb Exp $
+
+package com.threerings.media.tools.tile.xml;
+
+import java.awt.Dimension;
+import java.awt.Point;
+
+import org.xml.sax.Attributes;
+import org.apache.commons.digester.Digester;
+
+import com.samskivert.util.StringUtil;
+import com.samskivert.xml.CallMethodSpecialRule;
+
+import com.threerings.media.tile.TileSet;
+import com.threerings.media.tile.ObjectTileSet;
+
+/**
+ * Parses {@link ObjectTileSet} instances from a tileset description. An
+ * object tileset description looks like so:
+ *
+ * <pre>
+ * &lt;tileset name="Sample Object Tileset"&gt;
+ *   &lt;imagePath&gt;path/to/image.png&lt;/imagePath&gt;
+ *   &lt;!-- the widths (per row) of each tile in pixels --&gt;
+ *   &lt;widths&gt;265&lt;/widths&gt;
+ *   &lt;!-- the heights (per row) of each tile in pixels --&gt;
+ *   &lt;heights&gt;224&lt;/heights&gt;
+ *   &lt;!-- the number of tiles in each row --&gt;
+ *   &lt;tileCounts&gt;4&lt;/tileCounts&gt;
+ *   &lt;!-- the offset in pixels to the upper left tile --&gt;
+ *   &lt;offsetPos&gt;0, 0&lt;/offsetPos&gt;
+ *   &lt;!-- the gap between tiles in pixels --&gt;
+ *   &lt;gapSize&gt;0, 0&lt;/gapSize&gt;
+ *   &lt;!-- the widths (in unit tile count) of the objects --&gt;
+ *   &lt;objectWidths&gt;4, 3, 4, 3&lt;/objectWidths&gt;
+ *   &lt;!-- the heights (in unit tile count) of the objects --&gt;
+ *   &lt;objectHeights&gt;3, 4, 3, 4&lt;/objectHeights&gt;
+ * &lt;/tileset&gt;
+ * </pre>
+ */
+public class ObjectTileSetRuleSet extends TileSetRuleSet
+{
+    // documentation inherited
+    public void addRuleInstances (Digester digester)
+    {
+        super.addRuleInstances(digester);
+
+        digester.addRule(
+            _prefix + TILESET_PATH + "/objectWidths",
+            new CallMethodSpecialRule(digester) {
+                public void parseAndSet (String bodyText, Object target)
+                {
+                    int[] widths = StringUtil.parseIntArray(bodyText);
+                    ((ObjectTileSet)target).setObjectWidths(widths);
+                }
+            });
+
+        digester.addRule(
+            _prefix + TILESET_PATH + "/objectHeights",
+            new CallMethodSpecialRule(digester) {
+                public void parseAndSet (String bodyText, Object target)
+                {
+                    int[] heights = StringUtil.parseIntArray(bodyText);
+                    ((ObjectTileSet)target).setObjectHeights(heights);
+                }
+            });
+    }
+
+    // documentation inherited
+    protected Class getTileSetClass ()
+    {
+        return ObjectTileSet.class;
+    }
+}
diff --git a/src/java/com/threerings/media/tile/tools/xml/SwissArmyTileSetRuleSet.java b/src/java/com/threerings/media/tile/tools/xml/SwissArmyTileSetRuleSet.java
index 2d49e0362..ea59d27c4 100644
--- a/src/java/com/threerings/media/tile/tools/xml/SwissArmyTileSetRuleSet.java
+++ b/src/java/com/threerings/media/tile/tools/xml/SwissArmyTileSetRuleSet.java
@@ -1,5 +1,5 @@
 //
-// $Id: SwissArmyTileSetRuleSet.java,v 1.6 2001/11/29 20:39:37 mdb Exp $
+// $Id: SwissArmyTileSetRuleSet.java,v 1.7 2001/11/29 21:58:15 mdb Exp $
 
 package com.threerings.media.tools.tile.xml;
 
@@ -12,6 +12,7 @@ import org.apache.commons.digester.Digester;
 import com.samskivert.util.StringUtil;
 import com.samskivert.xml.CallMethodSpecialRule;
 
+import com.threerings.media.Log;
 import com.threerings.media.tile.TileSet;
 import com.threerings.media.tile.SwissArmyTileSet;
 
@@ -95,6 +96,36 @@ public class SwissArmyTileSetRuleSet extends TileSetRuleSet
             });
     }
 
+    // documentation inherited
+    public boolean isValid (Object target)
+    {
+        SwissArmyTileSet set = (SwissArmyTileSet)target;
+        boolean valid = super.isValid(target);
+
+        // check for a <widths> element
+        if (set.getWidths() == null) {
+            Log.warning("Tile set definition missing valid <widths> " +
+                        "element [set=" + set + "].");
+            valid = false;
+        }
+
+        // check for a <heights> element
+        if (set.getHeights() == null) {
+            Log.warning("Tile set definition missing valid <heights> " +
+                        "element [set=" + set + "].");
+            valid = false;
+        }
+
+        // check for a <tileCounts> element
+        if (set.getTileCounts() == null) {
+            Log.warning("Tile set definition missing valid <tileCounts> " +
+                        "element [set=" + set + "].");
+            valid = false;
+        }
+
+        return valid;
+    }
+
     // documentation inherited
     protected Class getTileSetClass ()
     {
diff --git a/src/java/com/threerings/media/tile/tools/xml/TileSetRuleSet.java b/src/java/com/threerings/media/tile/tools/xml/TileSetRuleSet.java
index e8bb099c6..009b9f5de 100644
--- a/src/java/com/threerings/media/tile/tools/xml/TileSetRuleSet.java
+++ b/src/java/com/threerings/media/tile/tools/xml/TileSetRuleSet.java
@@ -1,5 +1,5 @@
 //
-// $Id: TileSetRuleSet.java,v 1.4 2001/11/21 02:42:15 mdb Exp $
+// $Id: TileSetRuleSet.java,v 1.5 2001/11/29 21:58:15 mdb Exp $
 
 package com.threerings.media.tools.tile.xml;
 
@@ -9,6 +9,11 @@ import org.apache.commons.digester.Digester;
 import org.apache.commons.digester.Rule;
 import org.apache.commons.digester.RuleSetBase;
 
+import com.samskivert.util.StringUtil;
+import com.samskivert.xml.ValidatedSetNextRule;
+import com.samskivert.xml.ValidatedSetNextRule.Validator;
+
+import com.threerings.media.Log;
 import com.threerings.media.tile.TileSet;
 
 /**
@@ -16,7 +21,8 @@ import com.threerings.media.tile.TileSet;
  * instance. Derived classes would extend this and add rules for their own
  * special tilesets.
  */
-public abstract class TileSetRuleSet extends RuleSetBase
+public abstract class TileSetRuleSet
+    extends RuleSetBase implements Validator
 {
     /** The component of the digester path that is appended by the tileset
      * rule set to match a tileset. This is appended to whatever prefix is
@@ -69,6 +75,33 @@ public abstract class TileSetRuleSet extends RuleSetBase
             _prefix + TILESET_PATH + "/imagePath", "setImagePath", 0);
     }
 
+    /**
+     * The ruleset can be provided to a {@link ValidatedSetNextRule} to
+     * ensure that the tileset was fully parsed before doing something
+     * with it.
+     */
+    public boolean isValid (Object target)
+    {
+        TileSet set = (TileSet)target;
+        boolean valid = true;
+
+        // check for the 'name' attribute
+        if (StringUtil.blank(set.getName())) {
+            Log.warning("Tile set definition missing 'name' attribute " +
+                        "[set=" + set + "].");
+            valid = false;
+        }
+
+        // check for an <imagePath> element
+        if (StringUtil.blank(set.getImagePath())) {
+            Log.warning("Tile set definition missing <imagePath> element " +
+                        "[set=" + set + "].");
+            valid = false;
+        }
+
+        return valid;
+    }
+
     /**
      * A tileset rule set will create tilesets of a particular class,
      * which must be provided by the derived class via this method.
diff --git a/src/java/com/threerings/media/tile/tools/xml/UniformTileSetRuleSet.java b/src/java/com/threerings/media/tile/tools/xml/UniformTileSetRuleSet.java
index 9b4d7445f..1bdf122ac 100644
--- a/src/java/com/threerings/media/tile/tools/xml/UniformTileSetRuleSet.java
+++ b/src/java/com/threerings/media/tile/tools/xml/UniformTileSetRuleSet.java
@@ -1,11 +1,12 @@
 //
-// $Id: UniformTileSetRuleSet.java,v 1.5 2001/11/29 20:39:37 mdb Exp $
+// $Id: UniformTileSetRuleSet.java,v 1.6 2001/11/29 21:58:15 mdb Exp $
 
 package com.threerings.media.tools.tile.xml;
 
 import org.xml.sax.Attributes;
 import org.apache.commons.digester.Digester;
 
+import com.threerings.media.Log;
 import com.threerings.media.tile.TileSet;
 import com.threerings.media.tile.UniformTileSet;
 
@@ -43,6 +44,36 @@ public class UniformTileSetRuleSet extends TileSetRuleSet
             new Class[] { java.lang.Integer.TYPE });
     }
 
+    // documentation inherited
+    public boolean isValid (Object target)
+    {
+        UniformTileSet set = (UniformTileSet)target;
+        boolean valid = super.isValid(target);
+
+        // check for a <width> element
+        if (set.getWidth() == 0) {
+            Log.warning("Tile set definition missing valid <width> " +
+                        "element [set=" + set + "].");
+            valid = false;
+        }
+
+        // check for a <height> element
+        if (set.getHeight() == 0) {
+            Log.warning("Tile set definition missing valid <height> " +
+                        "element [set=" + set + "].");
+            valid = false;
+        }
+
+        // check for a <tileCount> element
+        if (set.getTileCount() == 0) {
+            Log.warning("Tile set definition missing valid <tileCount> " +
+                        "element [set=" + set + "].");
+            valid = false;
+        }
+
+        return valid;
+    }
+
     // documentation inherited
     protected Class getTileSetClass ()
     {
diff --git a/src/java/com/threerings/media/tile/tools/xml/XMLTileSetParser.java b/src/java/com/threerings/media/tile/tools/xml/XMLTileSetParser.java
index 5093fa261..1e794f517 100644
--- a/src/java/com/threerings/media/tile/tools/xml/XMLTileSetParser.java
+++ b/src/java/com/threerings/media/tile/tools/xml/XMLTileSetParser.java
@@ -1,5 +1,5 @@
 //
-// $Id: XMLTileSetParser.java,v 1.4 2001/11/27 22:06:39 mdb Exp $
+// $Id: XMLTileSetParser.java,v 1.5 2001/11/29 21:58:15 mdb Exp $
 
 package com.threerings.media.tools.tile.xml;
 
@@ -16,6 +16,7 @@ import org.apache.commons.digester.Digester;
 import org.apache.commons.digester.Rule;
 
 import com.samskivert.util.ConfigUtil;
+import com.samskivert.xml.ValidatedSetNextRule;
 
 import com.threerings.media.Log;
 import com.threerings.media.tile.TileSet;
@@ -57,8 +58,10 @@ public class XMLTileSetParser
 
         // add a set next rule which will put tilesets with this prefix
         // into the array list that'll be on the top of the stack
-        _digester.addSetNext(prefix + TileSetRuleSet.TILESET_PATH,
-                             "add", "java.lang.Object");
+        _digester.addRule(prefix + TileSetRuleSet.TILESET_PATH,
+                          new ValidatedSetNextRule(_digester, 
+                                                   "add", Object.class,
+                                                   ruleset));
     }
 
     /**