diff --git a/README.md b/README.md
index f543a3d..6f7714f 100644
--- a/README.md
+++ b/README.md
@@ -56,6 +56,8 @@ You can always find the most up-to-date [API documentation here](https://mod-con
 
 ## Data Model
 
+> **Note on Units**: All units decsribing the geometry of prefab elements are expressed in **millimeters (mm)** unless otherwise specified.
+
 ```mermaid
 erDiagram
     PrefabElement {
diff --git a/src/types/common/boundingBoxSchema.ts b/src/types/common/boundingBoxSchema.ts
index a42c181..b1b1315 100644
--- a/src/types/common/boundingBoxSchema.ts
+++ b/src/types/common/boundingBoxSchema.ts
@@ -1,12 +1,19 @@
 import { z } from "zod";
 
-const BoundingBoxSchema = z.object({
-    width: z.number().gt(0, "Width must be greater than 0"),
-    height: z.number().gt(0, "Height must be greater than 0"),
-    depth: z.number().gt(0, "Depth must be greater than 0")
+const BoundingBoxSchema = z.object({  
+  max: z.tuple([
+    z.number().positive(),  
+    z.number().positive(),  
+    z.number().positive()  
+  ]).describe("Maximum corner in millimeters and defined in the local coordianate system"),
+  
 }).openapi({
-    description: "The bounding box of an element in millimeters.",
+  description: "Local bounding box aligned to element's own axes, origin at (0,0,0). Dimensions in millimeters."
 });
 
 type BoundingBox = z.infer<typeof BoundingBoxSchema>;
-export { BoundingBoxSchema, BoundingBox };
\ No newline at end of file
+
+export { 
+  BoundingBoxSchema,
+  BoundingBox,
+};
\ No newline at end of file
diff --git a/src/types/common/dimensionalAttributesSchema.ts b/src/types/common/dimensionalAttributesSchema.ts
index eecb412..d96e5a7 100644
--- a/src/types/common/dimensionalAttributesSchema.ts
+++ b/src/types/common/dimensionalAttributesSchema.ts
@@ -2,9 +2,18 @@ import { z } from "zod";
 import { RangeSchema } from "./rangeSchema";
 
 const DimensionalAttributesSchema = z.object({
-    width: RangeSchema,
-    height: RangeSchema,
-    length: RangeSchema
+    length: RangeSchema.describe("Primary dimension along the longest horizontal axis of the element. Used for linear elements like beams, walls, and slabs."),
+    width: RangeSchema.describe("Secondary horizontal dimension perpendicular to length. Used for planar elements like slabs, walls, and panels."),
+    height: RangeSchema.describe("Vertical dimension. Defines the elevation of elements like walls and columns."),
+    depth: RangeSchema.describe("Cross-sectional dimension of structural members like beams and columns."),
+    thickness: RangeSchema.describe("Smallest dimension of planar elements such as walls, slabs, or panels. Represents the cross-sectional depth."),
+    radius: RangeSchema.describe("Radius of circular or cylindrical elements like columns, piles, or pipes."),
+}).openapi({
+  description: 
+  "Dimensional attributes defining the physical size of prefab elements. " +
+    "All dimensions are optional and dependent on element type. " +
+    "All measurements are in millimeters (mm). " +
+    "Ranges represent manufacturing constraints.",
 });
 
 type DimensionalAttributes = z.infer<typeof DimensionalAttributesSchema>;
diff --git a/src/types/entities/prefabElementSchema.ts b/src/types/entities/prefabElementSchema.ts
index aa3da33..02c9abf 100644
--- a/src/types/entities/prefabElementSchema.ts
+++ b/src/types/entities/prefabElementSchema.ts
@@ -49,9 +49,9 @@ const PrefabElementSchema = z.object({
             example: "This CLT wall panel is suitable for multi-story residential buildings and meets fire resistance standards."
         }),
     boundingBox: BoundingBoxSchema
-        .describe("3D bounding dimensions of the prefab element.")
+        .describe("3D bounding dimensions of the prefab element, located at the Local Origin (0,0,0).")
         .openapi({
-            description: "3D bounding dimensions of the prefab element, defining its spatial envelope."
+            description: "3D bounding dimensions of the prefab element, located at the local origin (0,0,0)."
         }),
     images: z.array(z.string()).min(1, "At least one image is required")
         .describe("Image URLs of the element")