diff --git a/plugins/LayerView/LayerView.qml b/plugins/LayerView/LayerView.qml
index ad363af4aa..b26d301648 100644
--- a/plugins/LayerView/LayerView.qml
+++ b/plugins/LayerView/LayerView.qml
@@ -10,16 +10,16 @@ import UM 1.0 as UM
 
 Item 
 {
-    width: UM.Theme.sizes.button.width
-    height: UM.Theme.sizes.slider_layerview_size.height
+    width: UM.Theme.getSize("button").width
+    height: UM.Theme.getSize("slider_layerview_size").height
 
     Slider 
     {
         id: slider
-        width: UM.Theme.sizes.slider_layerview_size.width
-        height: UM.Theme.sizes.slider_layerview_size.height
+        width: UM.Theme.getSize("slider_layerview_size").width
+        height: UM.Theme.getSize("slider_layerview_size").height
         anchors.left: parent.left
-        anchors.leftMargin: UM.Theme.sizes.slider_layerview_margin.width/2
+        anchors.leftMargin: UM.Theme.getSize("slider_layerview_margin").width/2
         orientation: Qt.Vertical
         minimumValue: 0;
         maximumValue: UM.LayerView.numLayers;
@@ -34,11 +34,11 @@ Item
         anchors.left: parent.left
         anchors.verticalCenter: parent.verticalCenter
         z: slider.z - 1
-        width: UM.Theme.sizes.slider_layerview_background.width
-        height: slider.height + UM.Theme.sizes.default_margin.height * 2
-        color: UM.Theme.colors.tool_panel_background;
-        border.width: UM.Theme.sizes.default_lining.width
-        border.color: UM.Theme.colors.lining
+        width: UM.Theme.getSize("slider_layerview_background").width
+        height: slider.height + UM.Theme.getSize("default_margin").height * 2
+        color: UM.Theme.getColor("tool_panel_background");
+        border.width: UM.Theme.getSize("default_lining").width
+        border.color: UM.Theme.getColor("lining")
 
         MouseArea {
             id: sliderMouseArea
diff --git a/plugins/PerObjectSettingsTool/PerObjectSettingsPanel.qml b/plugins/PerObjectSettingsTool/PerObjectSettingsPanel.qml
index f64e3d4935..087c100f2c 100644
--- a/plugins/PerObjectSettingsTool/PerObjectSettingsPanel.qml
+++ b/plugins/PerObjectSettingsTool/PerObjectSettingsPanel.qml
@@ -22,13 +22,13 @@ Item {
         anchors.top: parent.top;
         anchors.left: parent.left;
 
-        spacing: UM.Theme.sizes.default_margin.height;
+        spacing: UM.Theme.getSize("default_margin").height;
 
         UM.SettingItem {
             id: profileSelection
 
-            width: UM.Theme.sizes.setting.width;
-            height: UM.Theme.sizes.setting.height;
+            width: UM.Theme.getSize("setting").width;
+            height: UM.Theme.getSize("setting").height;
 
             name: catalog.i18nc("@label", "Object profile")
             type: "enum"
@@ -48,8 +48,8 @@ Item {
 
         Column {
             id: customisedSettings
-            spacing: UM.Theme.sizes.default_lining.height;
-            width: UM.Theme.sizes.setting.width + UM.Theme.sizes.setting.height/2;
+            spacing: UM.Theme.getSize("default_lining").height;
+            width: UM.Theme.getSize("setting").width + UM.Theme.getSize("setting").height/2;
 
             Repeater {
                 id: settings;
@@ -57,8 +57,8 @@ Item {
                 model: UM.ActiveTool.properties.getValue("Model").getItem(base.currentIndex).settings
 
                 UM.SettingItem {
-                    width: UM.Theme.sizes.setting.width;
-                    height: UM.Theme.sizes.setting.height;
+                    width: UM.Theme.getSize("setting").width;
+                    height: UM.Theme.getSize("setting").height;
 
                     name: model.label;
                     type: model.type;
@@ -80,8 +80,8 @@ Item {
                     {
                         anchors.left: parent.right;
 
-                        width: UM.Theme.sizes.setting.height;
-                        height: UM.Theme.sizes.setting.height;
+                        width: UM.Theme.getSize("setting").height;
+                        height: UM.Theme.getSize("setting").height;
 
                         onClicked: UM.ActiveTool.properties.getValue("Model").removeSettingOverride(UM.ActiveTool.properties.getValue("Model").getItem(base.currentIndex).id, model.key)
 
@@ -98,8 +98,8 @@ Item {
                                     height: parent.height/2
                                     sourceSize.width: width
                                     sourceSize.height: width
-                                    color: control.hovered ? UM.Theme.colors.setting_control_button_hover : UM.Theme.colors.setting_control_button
-                                    source: UM.Theme.icons.cross1
+                                    color: control.hovered ? UM.Theme.getColor("setting_control_button_hover") : UM.Theme.getColor("setting_control_button")
+                                    source: UM.Theme.getIcon("cross1")
                                 }
                             }
                         }
@@ -112,7 +112,7 @@ Item {
         {
             id: customise_settings_button;
             anchors.right: profileSelection.right;
-            height: UM.Theme.sizes.setting.height;
+            height: UM.Theme.getSize("setting").height;
             visible: parseInt(UM.Preferences.getValue("cura/active_mode")) == 1
 
             text: catalog.i18nc("@action:button", "Add Setting");
@@ -123,16 +123,16 @@ Item {
                 {
                     width: control.width;
                     height: control.height;
-                    border.width: UM.Theme.sizes.default_lining.width;
-                    border.color: control.pressed ? UM.Theme.colors.action_button_active_border :
-                                  control.hovered ? UM.Theme.colors.action_button_hovered_border : UM.Theme.colors.action_button_border
-                    color: control.pressed ? UM.Theme.colors.action_button_active :
-                           control.hovered ? UM.Theme.colors.action_button_hovered : UM.Theme.colors.action_button
+                    border.width: UM.Theme.getSize("default_lining").width;
+                    border.color: control.pressed ? UM.Theme.getColor("action_button_active_border") :
+                                  control.hovered ? UM.Theme.getColor("action_button_hovered_border") : UM.Theme.getColor("action_button_border")
+                    color: control.pressed ? UM.Theme.getColor("action_button_active") :
+                           control.hovered ? UM.Theme.getColor("action_button_hovered") : UM.Theme.getColor("action_button")
                 }
                 label: Label
                 {
                     text: control.text;
-                    color: UM.Theme.colors.setting_control_text;
+                    color: UM.Theme.getColor("setting_control_text");
                     anchors.centerIn: parent
                 }
             }
@@ -181,7 +181,7 @@ Item {
             }
 
             Column {
-                width: view.width - UM.Theme.sizes.default_margin.width * 2;
+                width: view.width - UM.Theme.getSize("default_margin").width * 2;
                 height: childrenRect.height;
 
                 Repeater {
@@ -212,11 +212,11 @@ Item {
                                 }
                                 label: Row
                                 {
-                                    spacing: UM.Theme.sizes.default_margin.width;
+                                    spacing: UM.Theme.getSize("default_margin").width;
                                     Image
                                     {
                                         anchors.verticalCenter: parent.verticalCenter;
-                                        source: control.checked ? UM.Theme.icons.arrow_right : UM.Theme.icons.arrow_bottom;
+                                        source: control.checked ? UM.Theme.getIcon("arrow_right") : UM.Theme.getIcon("arrow_bottom");
                                     }
                                     Label
                                     {
@@ -260,7 +260,7 @@ Item {
 
                                 delegate: ToolButton {
                                     id: button;
-                                    x: model.depth * UM.Theme.sizes.default_margin.width;
+                                    x: model.depth * UM.Theme.getSize("default_margin").width;
                                     text: model.name;
                                     tooltip: model.description;
                                     visible: !model.global_only
diff --git a/plugins/USBPrinting/ControlWindow.qml b/plugins/USBPrinting/ControlWindow.qml
index efe1e21b25..553da23fed 100644
--- a/plugins/USBPrinting/ControlWindow.qml
+++ b/plugins/USBPrinting/ControlWindow.qml
@@ -21,7 +21,7 @@ UM.Dialog
         anchors.fill: parent;
         Row
         {
-            spacing: UM.Theme.sizes.default_margin.width;
+            spacing: UM.Theme.getSize("default_margin").width;
             Text
             {
                 //: USB Printing dialog label, %1 is head temperature
diff --git a/resources/qml/AboutDialog.qml b/resources/qml/AboutDialog.qml
index e3e9f8e9b7..eb8795c5a6 100644
--- a/resources/qml/AboutDialog.qml
+++ b/resources/qml/AboutDialog.qml
@@ -24,7 +24,7 @@ UM.Dialog
         width: parent.width * 0.75
         height: width * (1/4.25)
 
-        source: UM.Theme.images.logo
+        source: UM.Theme.getImage("logo")
 
         sourceSize.width: width
         sourceSize.height: height
diff --git a/resources/qml/Cura.qml b/resources/qml/Cura.qml
index c291f6178c..f320e03e67 100644
--- a/resources/qml/Cura.qml
+++ b/resources/qml/Cura.qml
@@ -400,7 +400,7 @@ UM.MainWindow
                     bottomMargin: UM.Theme.getSize("default_margin").height;
                 }
 
-                source: UM.Theme.images.logo;
+                source: UM.Theme.getImage("logo");
                 width: UM.Theme.getSize("logo").width;
                 height: UM.Theme.getSize("logo").height;
                 z: -1;
diff --git a/resources/qml/SidebarHeader.qml b/resources/qml/SidebarHeader.qml
index 2875332872..adc29a3daf 100644
--- a/resources/qml/SidebarHeader.qml
+++ b/resources/qml/SidebarHeader.qml
@@ -161,30 +161,30 @@ Item
     Rectangle {
         id: materialSelectionRow
         anchors.top: variantRow.bottom
-        anchors.topMargin: UM.MachineManager.hasMaterials ? UM.Theme.sizes.default_margin.height : 0
+        anchors.topMargin: UM.MachineManager.hasMaterials ? UM.Theme.getSize("default_margin").height : 0
         width: base.width
-        height: UM.MachineManager.hasMaterials ? UM.Theme.sizes.sidebar_setup.height : 0
+        height: UM.MachineManager.hasMaterials ? UM.Theme.getSize("sidebar_setup").height : 0
         visible: UM.MachineManager.hasMaterials
 
         Label{
             id: materialSelectionLabel
             text: catalog.i18nc("@label","Material:");
             anchors.left: parent.left
-            anchors.leftMargin: UM.Theme.sizes.default_margin.width;
+            anchors.leftMargin: UM.Theme.getSize("default_margin").width;
             anchors.verticalCenter: parent.verticalCenter
             width: parent.width/100*45
-            font: UM.Theme.fonts.default;
-            color: UM.Theme.colors.text;
+            font: UM.Theme.getFont("default");
+            color: UM.Theme.getColor("text");
         }
 
         ToolButton {
             id: materialSelection
             text: UM.MachineManager.activeMaterial
             width: parent.width/100*55
-            height: UM.Theme.sizes.setting_control.height
+            height: UM.Theme.getSize("setting_control").height
             tooltip: UM.MachineManager.activeMaterial;
             anchors.right: parent.right
-            anchors.rightMargin: UM.Theme.sizes.default_margin.width
+            anchors.rightMargin: UM.Theme.getSize("default_margin").width
             anchors.verticalCenter: parent.verticalCenter
             style: UM.Theme.styles.sidebar_header_button