# Editing Point Cloud Data

## 1. Overview

This document describes how to edit, clean up, and merge `.e57` point cloud files using **CloudCompare** — an open-source 3D point cloud and mesh processing tool. It covers the GUI workflow on macOS, Windows, and Ubuntu, and the headless command-line workflow useful for automation and CI pipelines.

The workflow is relevant whenever a captured scan needs to be trimmed (e.g. removing irrelevant scan stations, the operator, or environmental noise), or when multiple partial scans need to be combined into a single deliverable `.e57` for downstream consumers (Unity, Unreal, mapping back-ends, VPS pipelines, etc.).

### 1.1 What is .e57?

E57 is an open, vendor-neutral file format (ASTM E2807) for storing 3D imaging data — point clouds, images, and metadata produced by laser scanners and other 3D imaging systems. A single `.e57` typically contains multiple scans ("scan stations") stored as separate child clouds inside one container file.

### 1.2 Prerequisites

* A Mac, Windows, or Ubuntu workstation with at least 8 GB RAM (16 GB+ recommended for large scans).
* CloudCompare v2.13 or newer. Screenshots in this document are from v2.14.beta on macOS.
* One or more `.e57` files to work with.
* For the CLI section: terminal access and the CloudCompare binary on PATH (or its full install path).

***

## 2. Installing CloudCompare

Download the latest stable release for your operating system from the official site: <https://www.cloudcompare.org/release/>

### Platform-specific notes

* **macOS:** Download the `.dmg`, drag CloudCompare into `/Applications`. On first launch, right-click → Open to bypass Gatekeeper if the build is unsigned.
* **Windows:** Use the `.exe` installer. The installer adds CloudCompare to the Start menu and (optionally) the system PATH — enable the PATH option if you plan to use the CLI.
* **Ubuntu / Linux:** Install via Snap (`sudo snap install cloudcompare`) or build from source from the GitHub repository for the latest features.

***

## 3. Editing an .e57 in the GUI

The GUI flow is the simplest way to inspect, trim, and re-export a point cloud. The high-level steps are: open the file → inspect the DB Tree → delete or hide unwanted child clouds → save the parent back out as `.e57`.

### Step 1 — Launch CloudCompare

1. Open the CloudCompare application from the OS launcher.
2. You will see the empty workspace shown below — the **DB Tree** (top-left), **Properties** panel (bottom-left), the **3D View**, and the **Console** at the bottom.

<figure><img src="/files/LQjfxNryOXNecVDuXBrt" alt=""><figcaption></figcaption></figure>

*Figure 1 — CloudCompare main window on first launch.*

### Step 2 — Import the .e57 file

1. Go to **File → Open** (`⌘O` on macOS, `Ctrl+O` on Windows/Linux).
2. Browse to your `.e57` file and confirm.
3. If a **Global Shift / Scale** dialog appears (common for geo-referenced scans with very large coordinates), accept the suggested shift. This avoids floating-point precision issues during display.
4. After loading, the DB Tree shows the parent `.e57` node with one or more child clouds (one per scan station).

{% hint style="info" %}
Each child cloud in the DB Tree corresponds to a separate scan station inside the `.e57`. Toggle the checkbox to the left of any cloud to hide/show it in the 3D view without deleting it — useful for quickly identifying which station holds the data you want to remove.
{% endhint %}

### Step 3 — Delete or trim unwanted parts

There are two common operations:

* **Delete entire child clouds** (e.g. an entire scan station that captured the wrong area).
* **Crop a portion of a cloud** (e.g. remove the operator or background noise from one station).

#### 3.a Deleting full child clouds

1. In the DB Tree, click the first cloud you want to remove.
2. Shift-click or `⌘`/`Ctrl`-click to multi-select additional clouds.
3. Right-click the selection and choose **Delete** from the context menu (see figure below).
4. Confirm the deletion. The clouds are removed from the project (the original file on disk is unchanged until you save).

<figure><img src="/files/mzBT3vZ7FNzpNopqqV42" alt="" width="375"><figcaption></figcaption></figure>

*Figure 2 — Multi-select clouds in the DB Tree and choose Delete.*

#### 3.b Cropping inside a cloud (Segment tool)

1. Select the cloud you want to trim.
2. Activate the **Segment** tool (Edit → Segment, or the scissors icon).
3. Left-click in the 3D view to draw a polygon around the area you want to keep (or remove). Right-click to close the polygon.
4. Press **`I`** to keep points inside the polygon, or **`O`** to remove them. Press the green checkmark to confirm.
5. CloudCompare creates two children: `<name>.segmented` and `<name>.remaining`. Delete whichever one you don't want to keep.

### Step 4 — Save the cleaned file

1. In the DB Tree, select the **parent node** (the top-level `.e57` entry). Selecting the parent ensures all remaining children are exported together.
2. Go to **File → Save** (`⌘S` / `Ctrl+S`).

<figure><img src="/files/YS44dnC8uq5FAsLotkb9" alt=""><figcaption></figcaption></figure>

*Figure 3 — File → Save with the parent node selected.*

3. In the save dialog, enter a file name (e.g. `Cropped`) and choose **E57 cloud (\*.e57)** from the format dropdown. Click **Save**.

<figure><img src="/files/NjfVAr7yWyoleYcGffum" alt=""><figcaption></figcaption></figure>

*Figure 4 — Save dialog with file format set to E57 cloud (\*.e57).*

4. If prompted with E57 export options (compression, sensor info, normals, colors), accept the defaults unless you have a specific downstream constraint.

{% hint style="warning" %}
Always select the **PARENT** node before saving. Saving with only one child selected will export only that single cloud, not the full edited dataset.
{% endhint %}

***

## 4. Command-Line Workflow

CloudCompare ships with a powerful command-line mode that is ideal for automation, batch jobs, and CI pipelines. The CLI is invoked through the same binary as the GUI — it just runs headless when command-line flags are supplied.

### 4.1 Locating the binary

* **macOS:** `/Applications/CloudCompare.app/Contents/MacOS/CloudCompare`
* **Windows:** `C:\Program Files\CloudCompare\CloudCompare.exe`
* **Linux (Snap):** `cloudcompare.CloudCompare`

For brevity, the examples below use `cloudcompare` — substitute the full path or alias the binary in your shell, e.g.:

```bash
# macOS example - add to ~/.zshrc
alias cloudcompare="/Applications/CloudCompare.app/Contents/MacOS/CloudCompare"
```

### 4.2 Merging two .e57 files

This is the most common automation use case — combining multiple captures into a single deliverable `.e57`.

```bash
cloudcompare \
  -C_EXPORT_FMT E57 \
  -O "./Cloud_1.e57" \
  -O "./Cloud_2.e57" \
  -MERGE_CLOUDS \
  -SAVE_CLOUDS FILE "./SF_2.e57"
```

#### Flag reference

| Flag                       | Purpose                                       | Notes                                               |
| -------------------------- | --------------------------------------------- | --------------------------------------------------- |
| `-O <path>`                | Open a file. Repeat for multiple inputs.      | Order matters — inputs are loaded in sequence.      |
| `-C_EXPORT_FMT <FMT>`      | Set the default export format.                | Supported: E57, LAS, PLY, BIN, ASC, etc.            |
| `-MERGE_CLOUDS`            | Merge all currently loaded clouds into one.   | Run after all `-O` flags.                           |
| `-SAVE_CLOUDS FILE <path>` | Save the current cloud to a specific path.    | Without `FILE`, CloudCompare auto-names the output. |
| `-SS <method>`             | Subsample points (RANDOM / SPATIAL / OCTREE). | Useful before merging large clouds.                 |
| `-AUTO_SAVE OFF`           | Disable auto-saving intermediate steps.       | Recommended in pipelines to avoid clutter.          |
| `-SILENT`                  | Suppress GUI dialogs.                         | Essential for headless / CI runs.                   |

### 4.3 Useful CLI variants

#### Convert .e57 to .ply

```bash
cloudcompare \
  -SILENT \
  -O "./scan.e57" \
  -C_EXPORT_FMT PLY \
  -SAVE_CLOUDS FILE "./scan.ply"
```

#### Subsample then merge

```bash
cloudcompare \
  -AUTO_SAVE OFF \
  -C_EXPORT_FMT E57 \
  -O "./Cloud_1.e57" -SS SPATIAL 0.01 \
  -O "./Cloud_2.e57" -SS SPATIAL 0.01 \
  -MERGE_CLOUDS \
  -SAVE_CLOUDS FILE "./merged_subsampled.e57"
```

#### Batch-merge a folder of .e57 files (bash)

```bash
#!/usr/bin/env bash
set -euo pipefail

INPUT_DIR="./scans"
OUTPUT="./merged.e57"

INPUTS=()
for f in "$INPUT_DIR"/*.e57; do
  INPUTS+=("-O" "$f")
done

cloudcompare \
  -SILENT \
  -AUTO_SAVE OFF \
  -C_EXPORT_FMT E57 \
  "${INPUTS[@]}" \
  -MERGE_CLOUDS \
  -SAVE_CLOUDS FILE "$OUTPUT"

echo "Wrote $OUTPUT"
```

{% hint style="info" %}
**CLI tip:** Add `-SILENT` to suppress GUI dialogs and `-AUTO_SAVE OFF` to prevent CloudCompare from writing intermediate files to your working directory. Both are essential for clean CI runs.
{% endhint %}

***

## 5. References

* CloudCompare official site: <https://www.cloudcompare.org/>
* CloudCompare CLI documentation: <https://www.cloudcompare.org/doc/wiki/index.php/Command_line_mode>
* E57 format reference (libE57): <http://www.libe57.org/>
* ASTM E2807 standard for E57: <https://www.astm.org/e2807-11r19.html>


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