diff --git a/core/src/main/java/info/openrocket/core/database/Databases.java b/core/src/main/java/info/openrocket/core/database/Databases.java
index 0889233de..b6ade7c53 100644
--- a/core/src/main/java/info/openrocket/core/database/Databases.java
+++ b/core/src/main/java/info/openrocket/core/database/Databases.java
@@ -189,18 +189,35 @@ public class Databases {
 	 * @param type			the material type.
 	 * @param baseName		the base name of the material.
 	 * @param density		the density of the material.
+	 * @param group			the material group.
 	 * @return				the material object from the database or a new material.
 	 */
-	public static Material findMaterial(Material.Type type, String baseName, double density) {
+	public static Material findMaterial(Material.Type type, String baseName, double density, MaterialGroup group) {
 		Database<Material> db = getDatabase(type);
 		String name = trans.get("material", baseName);
 
 		for (Material m : db) {
-			if (m.getName().equalsIgnoreCase(name) && MathUtil.equals(m.getDensity(), density)) {
+			if (m.getName().equalsIgnoreCase(name) && MathUtil.equals(m.getDensity(), density) && m.getGroup() == group) {
 				return m;
 			}
 		}
-		return Material.newMaterial(type, name, density, true);
+		return Material.newMaterial(type, name, density, group, true);
+	}
+
+	/**
+	 * Find a material from the database or return a new user defined material if the specified
+	 * material with the specified density is not found.
+	 * <p>
+	 * This method will attempt to localize the material name to the current locale, or use
+	 * the provided name if unable to do so.
+	 *
+	 * @param type			the material type.
+	 * @param baseName		the base name of the material.
+	 * @param density		the density of the material.
+	 * @return				the material object from the database or a new material.
+	 */
+	public static Material findMaterial(Material.Type type, String baseName, double density) {
+		return findMaterial(type, baseName, density, null);
 	}
 	
 	/**
diff --git a/core/src/main/resources/l10n/messages.properties b/core/src/main/resources/l10n/messages.properties
index 6523eaaed..d51d999e0 100644
--- a/core/src/main/resources/l10n/messages.properties
+++ b/core/src/main/resources/l10n/messages.properties
@@ -939,6 +939,7 @@ custmatdlg.title.Custommaterial = Custom material
 custmatdlg.lbl.Materialname = Material name:
 custmatdlg.lbl.Materialtype = Material type:
 custmatdlg.lbl.Materialdensity = Material density:
+custmatdlg.lbl.MaterialGroup = Material group:
 custmatdlg.checkbox.Addmaterial = Add material to application database
 
 
diff --git a/swing/src/main/java/info/openrocket/swing/gui/dialogs/CustomMaterialDialog.java b/swing/src/main/java/info/openrocket/swing/gui/dialogs/CustomMaterialDialog.java
index 7561c914d..f868ae9e9 100644
--- a/swing/src/main/java/info/openrocket/swing/gui/dialogs/CustomMaterialDialog.java
+++ b/swing/src/main/java/info/openrocket/swing/gui/dialogs/CustomMaterialDialog.java
@@ -21,6 +21,7 @@ import javax.swing.JTextField;
 import info.openrocket.core.database.Databases;
 import info.openrocket.core.l10n.Translator;
 import info.openrocket.core.material.Material;
+import info.openrocket.core.material.MaterialGroup;
 import info.openrocket.core.startup.Application;
 
 import net.miginfocom.swing.MigLayout;
@@ -39,10 +40,11 @@ public class CustomMaterialDialog extends JDialog {
 	
 	private boolean okClicked = false;
 	private JComboBox<Material.Type> typeBox;
-	private JTextField nameField;
+	private final JTextField nameField;
 	private DoubleModel density;
-	private JSpinner densitySpinner;
-	private UnitSelector densityUnit;
+	private final JSpinner densitySpinner;
+	private final UnitSelector densityUnit;
+	private JComboBox<MaterialGroup> groupBox;
 	private JCheckBox addBox;
 
 	public CustomMaterialDialog(Window parent, Material material, boolean saveOption, boolean addToApplicationDatabase,
@@ -118,6 +120,17 @@ public class CustomMaterialDialog extends JDialog {
 		updateDensityModel();
 
 
+		// Material group
+		panel.add(new JLabel(trans.get("custmatdlg.lbl.MaterialGroup")));
+		groupBox = new JComboBox<>(MaterialGroup.ALL_GROUPS);
+		if (material != null && !material.isUserDefined()) {
+			groupBox.setSelectedItem(material.getEquivalentGroup());
+		} else {
+			groupBox.setSelectedItem(MaterialGroup.CUSTOM);
+		}
+		panel.add(groupBox, "span, growx, wrap");
+
+
 		// Save option
 		if (saveOption) {
 			//// Add material to application database
@@ -175,6 +188,7 @@ public class CustomMaterialDialog extends JDialog {
 		Material.Type type;
 		String name;
 		double materialDensity;
+		MaterialGroup group;
 		
 		if (typeBox != null) {
 			type = (Material.Type) typeBox.getSelectedItem();
@@ -183,10 +197,10 @@ public class CustomMaterialDialog extends JDialog {
 		}
 		
 		name = nameField.getText().trim();
-		
 		materialDensity = this.density.getValue();
+		group = (MaterialGroup) groupBox.getSelectedItem();
 		
-		return Databases.findMaterial(type, name, materialDensity);
+		return Databases.findMaterial(type, name, materialDensity, group);
 	}