---
title: "Freehand Sections"
slug: "cyclone-3dr-freehandsectionc"
updated: 2026-09-07T11:51:46Z
published: 2026-09-07T11:51:46Z
canonical: "rcdocs.leica-geosystems.com/cyclone-3dr-freehandsectionc"
---

> ## 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.

# Freehand Sections

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

This command computes one or several sections on one or several meshes on one plane. It also allows you to draw projected polylines on meshes.

> [!TIP]
> ### Requirements
> 
> Select the mesh(es) on which you want to calculate a section and launch the command.

**Best plane**

When using the first option, the plane is defined by the best plane of the clicked points:

1. **Click two points** on the plane. If the points are clicked on the mesh, the projection on the mesh is assumed. Once you have clicked the first two points, the software calculates the first section assuming the plane is perpendicular to the screen view.
2. **Click other points**. Every time you click a new point, a best plane is computed and the section is updated.

**Projected segments**

When using the second option, segments are recursively projected (indefinitely repeated) while the user clicks new points:

1. **Click two points** on the mesh(es) or on the view. Once you have clicked the first two points, the software calculates the projection of the segment defined by the two points onto the mesh(es) according to the screen view direction.
2. **Click other points**. Every time you click a new point, the software calculates the projection of the segment defined by the last two clicked points onto the mesh(es) according to the screen view direction.

> [!WARNING]
> ### Notes
> 
> - The result is one set of polylines or one polyline that you can explode in several segments with [Ungroup Polyline](/v1/docs/cyclone-3dr-ungrouppolylinesc) function or separate with [Cut Polyline](/v1/docs/cyclone-3dr-cutpolylinec) function depending on your needs.
> - You can use the freehand sections in order to separate a mesh ([Constraint Mesh](/v1/docs/cyclone-3dr-constraintmeshc)), to prepare a polyline for further sharp edge reconstruction ([Sharp Edges](/v1/docs/cyclone-3dr-sharpedgesc)), or to create a polyline network for CAD surface reconstruction.

> [!TIP]
> ### Tips & Tricks
> 
> - At any time, you can remove the last clicked point by pressing **Del** or **Backspace** key.
> - Press the **C** key to close the current polyline.

> [!NOTE]
> ### Technical information
> 
> Sections on an inspected mesh
> 
> If the sections are computed on the inspected mesh (considered as well as the reference or measure), the sections will keep the inspection values of the mesh. **It means that the hair diagram will not be, in most cases, in the plane of the section**. It depends on the type of inspection (2D or 3D).
> 
> Restriction: when a mesh was colored as the measure with a cloud as reference, this capability is not available.
> 
> Example of a hair diagram in 3D on a planar section:
> 
> ![SectionOnInspectedMesh_CADMesh.png](https://cdn.document360.io/820e11db-8ed5-45ae-ac86-f6b77dcb2aa7/Images/Documentation/SectionOnInspectedMesh-CADMesh-2.png)
> 
> ***CAD and mesh used to compute the inspection***
> 
> ![SectionOnInspectedMesh_ColorMeasure.png](https://cdn.document360.io/820e11db-8ed5-45ae-ac86-f6b77dcb2aa7/Images/Documentation/SectionOnInspectedMesh-ColorMeasure.png)
> 
> ***3D Inspection with colors applied on the 3D mesh***
> 
> ![SectionOnInspectedMesh_SectionPlaneY.png](https://cdn.document360.io/820e11db-8ed5-45ae-ac86-f6b77dcb2aa7/Images/Documentation/SectionOnInspectedMesh-SectionPlaneY.png)
> 
> ***Section on the inspection mesh (Y plane)***
> 
> ![SectionOnInspectedMesh_HairDiagram.png](https://cdn.document360.io/820e11db-8ed5-45ae-ac86-f6b77dcb2aa7/Images/Documentation/SectionOnInspectedMesh-HairDiagram.png)
> 
> ***Plane Y and hair diagram in 3D: direction of the deviation***
> 
> If you want to have a hair diagram on the plane of the section:
> 
> - Do an inspection in the direction of the plane and then do a section with this plane.
> - Do a section in the plane on both entities (reference and measure) and then do an inspection of this polyline/set of polylines.