# Materials II: Master Materials and Material Functions

A summarised guide on configuring a master material as well as creating and making use of material functions.

## Creating Master Materials
* Within the *Content browser* create a new material and open it in the *Material viewer* window.

* **Parameterise** the options which are intended to be used by instances. This is done by adding a **VectorParameter**, assigning it a **Parameter Name**, and assigning a **Group** under the **General** section of the *Details* pane.

* Thereafter, connect the **VectorParameter** node to the material parameter which is expected to change with instances (i.e base colour).

## Adding Textures to Master Materials
* As previously mentioned, asset textures can be changed by material instances at run time.

* Select the desired texture within the *Content browser*.

* Within the *Material viewer* window of the master material, hold the **T key** and click on an empty space to create a **Texture Sample** node. 

* **Right click** the texture sample and select **Convert to Parameter** to have the texture converted to a **texture object**. This now allows the texture to be modified in instances.

* Assign the texture object a **Parameter Name** and **Group**.

## Creating Material Functions
* Material functions are a way of sharing shader code between multiple materials.

* Within the *Content browser*, **right click** and select **Material Function** from the **Materials & Textures** option.

## Basic Material Function Example
* In this example, the goal is to configure the material function to implement basic texture tiling which can be shared between materials.

* Open the material function within its viewer to edit the function.

* Within the **Material Expression Function Output** section of the *Details* pane, enter an **Output Name** and **Description**. This defines the function name and a brief description of what it does.

* Add a **TextureCoordinate** node as well as a **Function Input** node. Within the function input, define an **Input Name**, **Description** and **Input Type**. The objective of this is to multiply the number of tiles.

* Add a **Multiply** node and connect the inputs to the **TextureCoordinate** and **Function Input** nodes.

* Connect the result of the **Multiply** node to the **Output TitleOut** node.

* Finally, select **Apply**.

* Adjusting the scalar function input will result in varying previewed output.

* This function can now be added to multiple materials and connected to the **Input UVs** of **texture parameters** to enable the tiling.