> For the complete documentation index, see [llms.txt](https://help.auxalia.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.auxalia.com/plant-tools/plantexpresstools/how-to-use/off-page-connector-manager/usage/user-interface/viewer.md).

# Viewer

This chapter explains how the Viewer works.

### <mark style="color:blue;">Zoom & Pan</mark>

The Viewer is the same Viewer as used in Plant 3D. When you click on a node in the trees (drawing or OPC) it will be loaded and zoomed onto in the Viewer. You can then use the middle mouse button to either zoom or pan.

![](https://2994090777-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FZH2AGHzvPfBW7YdaaGc0%2Fuploads%2Fgit-blob-174542aa46c01a147a723135973befcc1a951f0b%2FPET-OPCM-UI-041.png?alt=media)

If no drawing not even an empty one is open in Plant 3D and you select a drawing node the Viewer shows a message telling you to have at least one drawing open. Can even be an empty one.

![](https://2994090777-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FZH2AGHzvPfBW7YdaaGc0%2Fuploads%2Fgit-blob-cbdbaad12e940e76cd614f84ded0b2ba82409125%2FPET-OPCM-UI-051.png?alt=media)

As mentioned in [Left Toolbar](/plant-tools/plantexpresstools/how-to-use/off-page-connector-manager/usage/user-interface/left-toolbar.md) the viewer can be disabled by clicking on the Viewer toggle button.

![](https://2994090777-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FZH2AGHzvPfBW7YdaaGc0%2Fuploads%2Fgit-blob-95fa58c1f12409ed23db817a189de897d0d49000%2FPET-OPCM-UI-059.png?alt=media)