# Frames

When analyzing the stress-energy tensor the frame of observation influences the values that will be observed. In Warp Factory frame transformations are done on the stress-energy tensor using observer tetrads that can transform the tensor. Currently, this transformation occurs using the [doFrameTransfer](https://applied-physics.gitbook.io/warp-factory/modules/analyzer-module/doframetransfer) function and is an important step that is used in the [getEnergyConditions](https://applied-physics.gitbook.io/warp-factory/modules/analyzer-module/getenergyconditions) function which evaluates the observers for energy condition violations.

{% hint style="info" %}
Only the Eulerian frame is defined which is used to determine the energy conditions, see [#eulerian-frame](https://applied-physics.gitbook.io/warp-factory/modules/analyzer-module/doframetransfer#eulerian-frame "mention")for details on the computation of the frame. 
{% endhint %}

The following frames are defined within Warp Factory:

<table><thead><tr><th width="208">Frame</th><th>Description</th></tr></thead><tbody><tr><td>Eulerian</td><td>Local Eulerian stress-energy tensor at all points in spacetime. Note that this takes a specific spatial orientation in Warp Factory aligned with the coordinate system.</td></tr></tbody></table>