====Binding Expressions====

You can use //expressions// to change how values from an ARDI asset are translated into effects. 

These are most often used when you need to convert a measurement from raw units (ie. meters) to a value more suitable for an effect.

The basic format is...

<code>
[ <property name/number> ]
</code>

However, there are three expression types that can help change the value.

===Converting to Boolean===
<code>
[ <property name/number>|value1|value2|value3 ]
</code>

This expression results in a boolean (yes/no) value. When the property (for example, 'Mode') matches any one of the given values, the boolean is 'true'. Otherwise, it's 'false'. 

===Using Measurement Scales===
<code>
[ <property name/number>:%:<minimum>:<maximum>]
</code>

This uses the minimum and maximum scale of the measurement to rescale the value. It's most often used to convert properties from a raw value (for instance, tank level measured in meters) to a height (tank level measured in %).

Let's take a look at the following example...

**Tank Level** - Analogue value, 0.5 - 2.5m

If you used this expression... <code>[ Tank Level:%:0:100 ]</code>

Then you would get the following values....

^Input^Output^
|0.5|0 (0%)|
|1|25 (25%)|
|1.5|50 (50%)|
|2|75 (75%)|
|2.5|100 (100%)|

===Mathematical Transform===
<code>
[ <property name/number>:*:<offset>:<multiplier>]
</code>

This option allows you to add an offset and multiplier to your values.

Lets take a look at the last example, where we again want to convert a tank level in meters to a percentage.

**Tank Level** - Analogue value, 0.5 - 2.5m

To convert a 0.5-2.5 value to a 0-1 value, we need to first subtract 0.5, then multiply by 0.5. This gives us the following expression <code>[ Tank Level:*:-0.5:0.5 ]</code>

//NOTE - Where possible, please use the measurement-scale version of this function. This allows users to adjust your visual scales globally from the web interface, without needing to edit individual effect files.//

===Examples===
^Example^Description^
|<code>[ Level ]</code>|A simple copy of the property into the effect.|
|<code>[ Level|1 ]</code>|Is '1' when the property equals one, otherwise it's 0.|
|<code>[ Level|3|5|12 ]</code>|Is '1' when the property equals three, five or twelve, otherwise it's 0|
|<code>[ Level:%:0:100]</code>|Use the percentage of the property range. If the property has a range between 0 and 500, 500 results in an effect value of 100, 250 results in an effect of 50, 0 results in an effect of 0.|
|<code>[ Level:*:20:2 ]</code>|The first option is an //offset// (an amount added to the base) and the second option is a multiplier. In this example, 20 is added to the amount before it is multiplied by 2, so that 0=40, 50 = 140 etc.|