Use multi-comp fin splitting

core/src/net/sf/openrocket/rocketcomponent/FinSet.java

@@ -1421,6 +1421,45 @@ public abstract class FinSet extends ExternalComponent implements AxialPositiona
 		fireComponentChangeEvent(ComponentChangeEvent.MASS_CHANGE);
 	}
 
+	/**
+	 * Split the fin set into individual fins.
+	 * @return  A list of the new fin sets.
+	 */
+	public List<FinSet> splitFins() {
+		RocketComponent parent = getParent();
+		int index = parent.getChildPosition(this);
+		int count = getFinCount();
+		double base = getBaseRotation();
+
+		List<FinSet> splitFins = null;		// List of all the split fins
+
+		if (count > 1) {
+			parent.removeChild(index);
+			splitFins = new ArrayList<>();
+			for (int i = 0; i < count; i++) {
+				FinSet copy = (FinSet) this.copy();
+				copy.setFinCount(1);
+				copy.setBaseRotation(base + i * 2 * Math.PI / count);
+				copy.setName(copy.getName() + " #" + (i + 1));
+				copy.setOverrideMass(getOverrideMass() / getFinCount());
+				parent.addChild(copy, index + i);
+
+				splitFins.add(copy);
+			}
+		}
+
+		// Split fins for children
+		for (RocketComponent listener : configListeners) {
+			if (listener instanceof FinSet) {
+				((FinSet) listener).splitFins();
+				this.removeConfigListener(listener);
+			}
+		}
+
+		return splitFins;
+	}
+
+
 	// for debugging.  You can safely delete this method
 	public static String getPointDescr( final Coordinate[] points, final String name, final String indent){
 		return getPointDescr(Arrays.asList(points), name, indent);

swing/src/net/sf/openrocket/gui/configdialog/FinSetConfig.java

@@ -109,23 +109,8 @@ public abstract class FinSetConfig extends RocketComponentConfig {
 				SwingUtilities.invokeLater(new Runnable() {
 					@Override
 					public void run() {
-						RocketComponent parent = component.getParent();
-						int index = parent.getChildPosition(component);
-						int count = ((FinSet) component).getFinCount();
-						double base = ((FinSet) component).getBaseRotation();
-						if (count <= 1)
-							return;
-						
 						document.addUndoPosition("Split fin set");
-						parent.removeChild(index);
+						((FinSet) component).splitFins();
-						for (int i = 0; i < count; i++) {
-							FinSet copy = (FinSet) component.copy();
-							copy.setFinCount(1);
-							copy.setBaseRotation(base + i * 2 * Math.PI / count);
-							copy.setName(copy.getName() + " #" + (i + 1));
-							copy.setOverrideMass(((FinSet) component).getOverrideMass()/((FinSet) component).getFinCount());
-							parent.addChild(copy, index + i);
-						}
 					}
 				});