To create your own transformation effect, choose Effects->Trilinear filters->New from the main menu.
You will see the following screen:
For each pixel of the image or its part, the values of RGB components are multiplied by the central matrix element. The RGB components of the adjacent pixels are multiplied by the appropriate matrix elements. Then the results are added termwise (component by component) and divided by the Divider parameter. The division result is the new pixel color.
Click the Preview button to test the filter on the current image. No actual change will be applied to the image.
When you have finished tuning and testing your trilinear filter, click Add to save it.
To delete a custom transformation, choose Effects-> Trilinear filters-> Delete from the main menu, pick the filter you want to delete from the pull-down list and click "OK".