---
title: "Basic Tutorial | Compute inspection between polylines"
slug: "cyclone-3dr-exercise-compute-inspection-between-polylines"
updated: 2026-09-07T11:51:31Z
published: 2026-09-07T11:51:31Z
canonical: "rcdocs.leica-geosystems.com/cyclone-3dr-exercise-compute-inspection-between-polylines"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://rcdocs.leica-geosystems.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Basic Tutorial | Compute inspection between polylines

> [!TIP]
> Open the file **CrossSections.3dr** ([download](https://www.cyclone3dr.com/download_helper.php?File=Cyclone3DRSampleData/CrossSections.3dr)).

It contains:

- the mesh of a **measured tunnel**
- a **theoretical section** of the tunnel at a given kilometric point

Select and show these two elements only.

## Create a section of the measured mesh

As a first step, we will create a section of the measured mesh in the same plane as the theoretical section:

1. Select the mesh and launch [Planar Sections](/v1/docs/cyclone-3dr-planarsectionc),
2. Define the axis of the plane used to compute sections, choose the ![box.jpg](https://cdn.document360.io/820e11db-8ed5-45ae-ac86-f6b77dcb2aa7/Images/Documentation/box.jpg) option and click on the theoretical section,
3. Select the option **List of values** and click a point on the theoretical section,
4. Click **OK**. A section named **Planar Section 232.26** is added in the Planar Sections group.

![measuredMesh.png](https://cdn.document360.io/820e11db-8ed5-45ae-ac86-f6b77dcb2aa7/Images/Documentation/measuredMesh.png)

Section on the measured mesh

## Inspect the polylines

Select and show only the two polylines **Theoretical section** and **Planar Section 232.26**. Select first **Theoretical section**, as it is the reference, and then select **Planar Section 232.26** with **CTRL**, as it is the measure.

Launch the command [Compare Inspect Section vs Section](/v1/docs/cyclone-3dr-compareinspectsectionc).

1. Choose to apply the color on the reference object.
2. Uncheck all options and click **Preview** to compute the inspection, then click on **Edit color** to magnify the distances. Set Magnify to 11.
3. Click **OK** to validate the display. Then, click **OK** again to validate the inspection. A new object called **Comparison Theoretical section / Planar Section 232.26** is added in the Compare Inspect group.

![inspection2poly.png](https://cdn.document360.io/820e11db-8ed5-45ae-ac86-f6b77dcb2aa7/Images/Documentation/inspection2poly.png)

Inspection between two polylines