# Trace

### Description

Picks [items](https://renownedgames.gitbook.io/ai-tree/environment-query-system/items) based on condition that they can be traced with a ray from given object.

On top of common parameters that are listed above this test following parameters.

#### Parameters

| Name          | Description                                        |
| ------------- | -------------------------------------------------- |
| Trace To      | Object that needs to be traced to                  |
| Up Offset     | Vertical offset of tracing rays                    |
| Culling Layer | Layermask of layers that are "visible" for tracing |

### Example

In the picture below trace test is used to score [items](https://renownedgames.gitbook.io/ai-tree/environment-query-system/items) based on their visibility from querier position.

<figure><img src="https://2203000093-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FGOxTM7Aj9oiVaIINrEkE%2Fuploads%2FY9bDd7kttr5e8Xb9SalY%2FEQ%20tests%20trace.png?alt=media&#x26;token=acce5504-bb33-4ccd-9004-95bd7535459f" alt=""><figcaption></figcaption></figure>

To achieve this effect set Test Purpose to "Score Only". Set Score Sampling Operation to  "Multiply", set Filter Type to "Maximum" and then set Max Value to any non-negative value (in example it's zero). Then set Trace To to "Querier".

{% hint style="info" %}
For more information about querier visit [EQS Tester](https://renownedgames.gitbook.io/ai-tree/environment-query-system/useful-components/eqs-tester) tab.
{% endhint %}