diff --git a/backend/app/services/price_engine.py b/backend/app/services/price_engine.py
index b8239f1..6828a52 100644
--- a/backend/app/services/price_engine.py
+++ b/backend/app/services/price_engine.py
@@ -98,14 +98,24 @@ def _estimate_weight(file_info: FileInfo, density_g_cm3: float,
     logger.debug("Walls: perimeter=%.1f mm/layer, thickness=%.1f mm, volume=%.1f mm3",
                  perimeter_per_layer_mm, wall_thickness_total, wall_volume_mm3)
 
-    # Top + bottom solid layers volume
+    # Top + bottom solid layers volume (use interior footprint, excluding walls)
     solid_layers = TOP_SOLID_LAYERS + BOTTOM_SOLID_LAYERS
     solid_volume_mm3 = footprint_mm2 * layer_height_mm * solid_layers
     logger.debug("Solid top/bottom: footprint=%.1f mm2, layers=%d, volume=%.1f mm3",
                  footprint_mm2, solid_layers, solid_volume_mm3)
 
-    # Interior volume for infill (total volume minus walls minus top/bottom)
-    interior_volume_mm3 = max(volume_mm3 - wall_volume_mm3 - solid_volume_mm3, 0)
+    # Shell = walls + top/bottom. Cap at 75% of volume so infill always matters.
+    shell_volume_mm3 = wall_volume_mm3 + solid_volume_mm3
+    max_shell = volume_mm3 * 0.75
+    if shell_volume_mm3 > max_shell:
+        scale = max_shell / shell_volume_mm3
+        wall_volume_mm3 *= scale
+        solid_volume_mm3 *= scale
+        shell_volume_mm3 = max_shell
+        logger.debug("Shell capped: scale=%.2f, shell=%.1f mm3", scale, shell_volume_mm3)
+
+    # Interior volume for infill (total volume minus shell)
+    interior_volume_mm3 = volume_mm3 - shell_volume_mm3
     infill_volume_mm3 = interior_volume_mm3 * (infill_percent / 100.0)
     logger.debug("Infill: interior=%.1f mm3, infill%%=%d, infill_volume=%.1f mm3",
                  interior_volume_mm3, infill_percent, infill_volume_mm3)
@@ -152,11 +162,18 @@ def _estimate_print_time(file_info: FileInfo, layer_height_mm: float,
                  outer_wall_time_s, inner_wall_time_s, wall_time_s)
 
     # Infill time: total infill length / speed
-    # infill_length = infill_volume / (line_width * layer_height)
+    # Use weight-based total volume, then subtract shell (capped same as weight calc)
     total_filament_mm3 = weight_grams / density_g_cm3 * 1000.0
     wall_volume_mm3 = perimeter_per_layer_mm * WALL_COUNT * LINE_WIDTH_MM * layer_height_mm * num_layers
     solid_volume_mm3 = footprint_mm2 * layer_height_mm * (TOP_SOLID_LAYERS + BOTTOM_SOLID_LAYERS)
-    infill_volume_mm3 = max(total_filament_mm3 - wall_volume_mm3 - solid_volume_mm3, 0)
+    shell_volume_mm3 = wall_volume_mm3 + solid_volume_mm3
+    max_shell = volume_mm3 * 0.75
+    if shell_volume_mm3 > max_shell:
+        scale = max_shell / shell_volume_mm3
+        wall_volume_mm3 *= scale
+        solid_volume_mm3 *= scale
+        shell_volume_mm3 = max_shell
+    infill_volume_mm3 = max(total_filament_mm3 - shell_volume_mm3, 0)
     infill_length_mm = infill_volume_mm3 / (LINE_WIDTH_MM * layer_height_mm)
     infill_time_s = infill_length_mm / SPEED_INFILL
     logger.debug("Infill time: length=%.0f mm, time=%.0fs", infill_length_mm, infill_time_s)
diff --git a/frontend/src/views/MaterialsView.vue b/frontend/src/views/MaterialsView.vue
index 25eaf71..054e335 100644
--- a/frontend/src/views/MaterialsView.vue
+++ b/frontend/src/views/MaterialsView.vue
@@ -39,8 +39,9 @@
           </div>
 
           <div v-if="mat.color_options?.length" class="mt-3 flex flex-wrap gap-1.5">
-            <span v-for="c in mat.color_options" :key="c" class="rounded-full bg-gray-100 px-2 py-0.5 text-[10px] text-gray-600">
-              {{ c }}
+            <span v-for="c in mat.color_options" :key="c.hex" class="inline-flex items-center gap-1 rounded-full bg-gray-100 px-2 py-0.5 text-[10px] text-gray-600">
+              <span class="inline-block h-3 w-3 rounded-full border border-gray-300 flex-shrink-0" :style="{ backgroundColor: c.hex }"></span>
+              {{ c.name }}
             </span>
           </div>
         </div>