diff --git a/src/app_context.ts b/src/app_context.ts
index 0d22c37..7504a59 100644
--- a/src/app_context.ts
+++ b/src/app_context.ts
@@ -28,7 +28,8 @@ export class AppContext {
 
     private _workerController: WorkerController;
     private _lastAction?: EAction;
-    public maxConstraint?: Vector3;
+    public minConstraint?: { x: number, z: number };
+    public maxConstraint?: { x: number, z: number };
     private _materialManager: MaterialMapManager;
     private _loadedFilename: string | null;
 
@@ -109,8 +110,17 @@ export class AppContext {
             AppConsole.success(LOC('import.imported_mesh'));
             this._addWorkerMessagesToConsole(resultImport.messages);
 
+            UI.Get._ui.voxelise.components.constraintAxis.setValue('y');
+            UI.Get._ui.voxelise.components.size.setValue(80);
+
+            this.minConstraint = Vector3.copy(resultImport.result.dimensions)
+                .mulScalar(AppConfig.Get.CONSTRAINT_MINIMUM_HEIGHT).ceil();
             this.maxConstraint = Vector3.copy(resultImport.result.dimensions)
-                .mulScalar(AppConfig.Get.CONSTRAINT_MAXIMUM_HEIGHT / 8.0).floor();
+                .mulScalar(AppConfig.Get.CONSTRAINT_MAXIMUM_HEIGHT).floor();
+
+            UI.Get._ui.voxelise.components.constraintAxis.setOptionEnabled(0, this.minConstraint.x > 0 && this.minConstraint.x <= this.maxConstraint.x);
+            UI.Get._ui.voxelise.components.constraintAxis.setOptionEnabled(2, this.minConstraint.z > 0 && this.minConstraint.z <= this.maxConstraint.z);
+
             this._materialManager = new MaterialMapManager(resultImport.result.materials);
             UI.Get.updateMaterialsAction(this._materialManager);
 
diff --git a/src/ui/components/combobox.ts b/src/ui/components/combobox.ts
index af7d0eb..02c7e0c 100644
--- a/src/ui/components/combobox.ts
+++ b/src/ui/components/combobox.ts
@@ -55,6 +55,11 @@ export class ComboboxComponent<T> extends ConfigComponent<T, HTMLSelectElement>
         });
     }
 
+    public setOptionEnabled(index: number, enabled: boolean) {
+        const option = UIUtil.getElementById(this._getId() + '-' + index) as HTMLOptionElement;
+        option.disabled = !enabled;
+    }
+
     public override _generateInnerHTML() {
         const builder = new HTMLBuilder();
 
@@ -130,4 +135,8 @@ export class ComboboxComponent<T> extends ConfigComponent<T, HTMLSelectElement>
             }
         });
     }
+
+    public setValue(value: T) {
+        this._setValue(value);
+    }
 }
diff --git a/src/ui/components/slider.ts b/src/ui/components/slider.ts
index 49b8357..cdab22d 100644
--- a/src/ui/components/slider.ts
+++ b/src/ui/components/slider.ts
@@ -31,6 +31,10 @@ export class SliderComponent extends ConfigComponent<number, HTMLDivElement> {
         this._valueHovered = false;
     }
 
+    public setValue(value: number) {
+        this._setValue(value);
+    }
+
     public override setDefaultValue(value: number) {
         super.setDefaultValue(value);
         this._internalValue = value;
diff --git a/src/ui/layout.ts b/src/ui/layout.ts
index 3598d54..cb0e93f 100644
--- a/src/ui/layout.ts
+++ b/src/ui/layout.ts
@@ -33,6 +33,7 @@ import { VectorComponent } from './components/vector';
 import { AppConsole } from './console';
 import { AppIcons } from './icons';
 import { HTMLBuilder, MiscComponents } from './misc';
+import { AppConfig } from '../config';
 
 export type Group = {
     id: string,
@@ -83,7 +84,7 @@ export class UI {
     }
 
     public uiOrder = ['settings', 'import', 'materials', 'voxelise', 'assign', 'export'];
-    private _ui = {
+    public _ui = {
         'settings': {
             id: 'settings',
             label: LOC('settings.heading'),
@@ -130,20 +131,27 @@ export class UI {
                     .addItem({ payload: 'z', displayLocKey: 'voxelise.components.z_axis' })
                     .setLabel('voxelise.components.constraint_axis')
                     .addValueChangedListener((value: TAxis) => {
-                        /*
-                        TODO:
                         switch (value) {
-                            case 'x':
-                                this._ui.voxelise.components.size.setMax(this._appContext.maxConstraint?.x ?? 400);
+                            case 'x': {
+                                ASSERT(this._appContext !== undefined && this._appContext.minConstraint !== undefined && this._appContext.maxConstraint !== undefined);
+                                console.log('min', this._appContext.minConstraint, 'max', this._appContext.maxConstraint);
+                                this._ui.voxelise.components.size.setMin(this._appContext.minConstraint.x);
+                                this._ui.voxelise.components.size.setMax(this._appContext.maxConstraint.x);
                                 break;
-                            case 'y':
-                                this._ui.voxelise.components.size.setMax(this._appContext.maxConstraint?.y ?? AppConfig.Get.CONSTRAINT_MAXIMUM_HEIGHT);
+                            }
+                            case 'y': {
+                                this._ui.voxelise.components.size.setMin(AppConfig.Get.CONSTRAINT_MINIMUM_HEIGHT);
+                                this._ui.voxelise.components.size.setMax(AppConfig.Get.CONSTRAINT_MAXIMUM_HEIGHT);
                                 break;
-                            case 'z':
-                                this._ui.voxelise.components.size.setMax(this._appContext.maxConstraint?.z ?? 400);
+                            }
+                            case 'z': {
+                                ASSERT(this._appContext !== undefined && this._appContext.minConstraint !== undefined && this._appContext.maxConstraint !== undefined);
+                                console.log('min', this._appContext.minConstraint, 'max', this._appContext.maxConstraint);
+                                this._ui.voxelise.components.size.setMin(this._appContext.minConstraint.z);
+                                this._ui.voxelise.components.size.setMax(this._appContext.maxConstraint.z);
                                 break;
+                            }
                         }
-                        */
                     }),
                 'size': new SliderComponent()
                     .setMin(3)