---
title: "Trim Surface"
canonical: "https://help.innovyze.com/space/infodrainage2020v2/16417401/Trim%20Surface"
format: markdown
---
Trim Surface is used to define the boundary of the surface loaded in the  [Surface Data](https://help-innovyze.atlassian.net/wiki/spaces/infodrainage2020v2/pages/16417384) form to remove information that is not necessary by the design. I.e. if a large LIDAR tile has been simply loaded and it only requires a certain part of it.

![image](media://b6cedfbc-b1e3-4a94-9300-b2ced0a8b65f)


**Draw a polygon**

The *Drawing Mode* tool > Macro (inline-media-image)

 should be selected with no polygon drawn on the surface, then the drawing cursor > Macro (inline-media-image)

 will appear when entering on the plan.

- Draw a **rectangle**: left-click on the plan, hold down and band select the area. Release the mouse when finished.
- Draw a **polygon:** left-click on the plan to add the first point, then click as many time as you want to add points. Finish the polygon by right-clicking the mouse. During the drawing, you can press the 'Back' key to delete the last vertex, you can also cancel the drawing by pressing the 'Esc' key.


**Edit the polygon**

The *Drawing Mode *tool  > Macro (inline-media-image)

 should be selected to edit the polygon.

| **Action** | **Access** |
| --- | --- |
| Move a vertex | > Macro (legacy-content) |
| Add a vertex | > Macro (legacy-content) |
| Delete a vertex | > Macro (legacy-content) |
| Drag the polygon | > Macro (legacy-content) |
| Remove the polygon | > Macro (legacy-content) |


**Handle the plan**

- Zoom in/zoom out by rolling the wheel of the mouse.
- Band zoom an area by selecting the *Band Zoom* tool > Macro (inline-media-image)

, then the band zoom cursor  > Macro (inline-media-image)

 will appear when entering on the plan.
- Zoom to full size extents with the *Extent*s tool  > Macro (inline-media-image)

.
- Drag the plan by holding down the wheel of the mouse and move it.

**Trim the surface**

After drawing the polygon, the surface is automatically trimmed by clicking OK, then the updated data is displayed in [Surface Data](https://help-innovyze.atlassian.net/wiki/spaces/infodrainage2020v2/pages/16417384).

The surface will not be trimmed if the polygon has crossing edges.