Fix iridescence tooltip

com.unity.render-pipelines.high-definition/Documentation~/Material-Type.md

@@ -38,7 +38,7 @@ Unity exposes different properties for your Material depending on the **Material
 | **Anisotropy**                        | Use the slider to set the direction of the anisotropy effect. Negative values make the effect vertical, and positive values make the effect horizontal. This stretches the specular highlights in the given direction.<br />This property only appears when you select **Anisotropy** from the **Material Type** drop-down. |
 | **Anisotropy Map**                    | Assign a Texture, with values from 0 to 1, that controls the strength of the anisotropy effect. HDRP only uses the red channel of this Texture to calculate the strength of the effect.<br />This property only appears when you select **Anisotropy** from the **Material Type** drop-down. |
 | **Iridescence Mask**                  | Assign a Texture, with values from 0 to 1, that controls the strength of the iridescence effect. A texel with a value of 1 corresponds to full strength, while those with a value of 0 disables the iridescence effect.<br />This property only appears when you select **Iridescence** from the **Material Type** drop-down. |
-| **Iridescence Layer Thickness map**   | Assign a Texture, with values from 0 to 1, that controls the thickness of the iridescence. This modifies the color of the effect.<br />This property only appears when you select **Iridescence** from the **Material Type** drop-down. |
+| **Iridescence Layer Thickness map**   | Assign a Texture, with values from 0 to 1, that controls the thickness of the thin iridescence layer over the material. This modifies the color of the effect. Unit is micrometer multiplied by 3. A value of 1 is remapped to 3 micrometers or 3000 nanometers.<br />This property only appears when you select **Iridescence** from the **Material Type** drop-down. |
 | **Iridescence Layer Thickness remap** | Use this min-max slider to remap the thickness values from the **Iridescence Layer Thickness map** to the range you specify. Rather than [clamping](https://docs.unity3d.com/ScriptReference/Mathf.Clamp.html) values to the new range, Unity condenses the original range down to the new range uniformly.<br />This property only appears when you select **Iridescence** from the **Material Type** drop-down. |
 | **Specular Color**                    | Allows you to manually define the specular color. You can assign a Texture to define the specular color on a pixel level and use the color picker to select a global specular color for the Material. If you do both, HDRP multiplies each pixel of the Texture by the color you specify in the color picker.<br />This property only appears when you select **Specular Color** from the **Material Type** drop-down. |
 | **Energy Conserving Specular Color**  | Enable the checkbox to make HDRP reduce the diffuse color of the Material if the specular effect is more intense. This makes the lighting of the Material more consistent, which makes the Material look more physically accurate.<br />This property only appears when you select **Specular Color** from the **Material Type** drop-down. |

com.unity.render-pipelines.high-definition/Documentation~/snippets/shader-graph-blocks/iridescence-thickness.md

@@ -1,6 +1,6 @@
 <tr>
 <td>**Iridescence Thickness**</td>
-<td>The thickness of the iridescence. This changes the gradient of color that the iridescence effect produces.</td>
+<td>The thickness of the iridescence. This changes the gradient of color that the iridescence effect produces. Unit is micrometer multiplied by 3. A value of 1 is remapped to 3 micrometers or 3000 nanometers.</td>
 <td>&#8226; **Material Type** set to **StackLit** <br/>&#8226; **Iridescence** enabled.</td>
 <td>0.0</td>
 </tr>

com.unity.render-pipelines.high-definition/Editor/Material/UIBlocks/LitSurfaceInputsUIBlock.cs

@@ -92,7 +92,7 @@ internal class Styles
             // Iridescence
             public static GUIContent iridescenceMaskText = new GUIContent("Iridescence Mask", "Specifies the Iridescence Mask (R) for this Material - This map controls the intensity of the iridescence.");
             public static GUIContent iridescenceThicknessText = new GUIContent("Iridescence Layer Thickness");
-            public static GUIContent iridescenceThicknessMapText = new GUIContent("Iridescence Layer Thickness map", "Specifies the Iridescence Layer Thickness map (R) for this Material.");
+            public static GUIContent iridescenceThicknessMapText = new GUIContent("Iridescence Layer Thickness map", "Specifies the Thickness map (R) of the thin iridescence layer over the material. Unit is micrometer multiplied by 3. A value of 1 is remapped to 3 micrometers or 3000 nanometers.");
             public static GUIContent iridescenceThicknessRemapText = new GUIContent("Iridescence Layer Thickness remap");
 
             // Clear Coat