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• この教材は、「CloudCompareの基本操作 点群データ解析基礎演習(執筆者：早川裕弌（東京大学空間情報科学研究センター）)」(c)地形鮮明化プロジェクトCC BY NC SAを利用し作成したものです。.
• This is 'CloudCompare: Simple Point Cloud Crop' by Rich Oglesby on Vimeo, the home for high quality videos and the people who love them.

On CloudCompare Download page, click to download the CloudCompare 2.6.1 installer version for Windows 64 bits (or Windows 32 bits based on your operating system). When the downloading completes, double-click on the installer. Click 'Run' and 'Yes', if your system pops up windows for security reasons. When the CloudCompare setup wizard window shows.

PLY is a computer file format known as the Polygon File Format or the Stanford Triangle Format. It was principally designed to store three-dimensional data from 3D scanners. The data storage format supports a relatively simple description of a single object as a list of nominally flat polygons. A variety of properties can be stored, including: color and transparency, surface normals, texture coordinates and data confidence values. The format permits one to have different properties for the front and back of a polygon.There are two versions of the file format, one in ASCII, the other in binary.

The file format[edit]

Files are organised as a header, that specifies the elements of a mesh and their types, followed by the list of elements itself. The elements are usually vertices and faces, but may include other entities such as edges, samples of range maps, and triangle strips.

The header of both ASCII and binary files is ASCII text. Only the numerical data that follows the header is different between the two versions.The header always starts with a 'magic number', a line containing

which identifies the file as a PLY file. The second line indicates which variation of the PLY format this is. It should be one of:

Future versions of the standard will change the revision number at the end - but 1.0 is the only version currently in use.

Comments may be placed in the header by using the word comment at the start of the line. Everything from there until the end of the line should then be ignored. e.g.:

The 'element' keyword introduces a description of how some particular data element is stored and how many of them there are. Hence, in a file where there are 12 vertices, each represented as a floating point (X,Y,Z) triple, one would expect to see:

Other 'property' lines might indicate that colours or other data items are stored at each vertex and indicate the data type of that information. Regarding the data type there are two variants, depending on the source of the ply file. The type can be specified with one of char uchar short ushort int uint float double, or one of int8 uint8 int16 uint16 int32 uint32 float32 float64. For an object with ten polygonal faces, one might see:

The word 'list' indicates that the data is a list of values, the first of which is the number of entries in the list (represented as a 'uchar' in this case). Verilog syntax cheat sheet. In this example each list entry is represented as an 'int'. At the end of the header, there must always be the line:

ASCII or binary format[edit]

In the ASCII version of the format, the vertices and faces are each described one to a line with the numbers separated by white space. In the binary version, the data is simply packed closely together at the 'endianness' specified in the header and with the data types given in the 'property' records. For the common 'property list..' representation for polygons, the first number for that element is the number of vertices that the polygon has and the remaining numbers are the indices of those vertices in the preceding vertex list.

History[edit]

The PLY format was developed in the mid-90s by Greg Turk and others in the Stanford graphics lab under the direction of Marc Levoy. Its design was inspired by the Wavefront .obj format, but the Obj format lacked extensibility for arbitrary properties and groupings, so the 'property' and 'element' keywords were devised to generalize the notions of vertices, faces, associated data, and other groupings.

See also[edit]

• Wavefront .obj file, a 3D geometry definition file format with .obj file extension
• MeshLab: an open source Windows, Mac OS X and Linux application for visualizing, processing and converting three-dimensional meshes to or from the PLY file format.
• CloudCompare, another open source application for handling PLY files.
• Mathematica A technical computing system that can work with PLY files.

References[edit]

1. ^Greg Turk. 'The PLY Polygon File Format'. Archived from the original on 2016-12-04.CS1 maint: discouraged parameter (link)

External links[edit]

CloudCompare is a 3D point cloud processing software (such as those obtained with a laser scanner). It can also handle triangular meshes and calibrated images.

Originally created during a collaboration between Telecom ParisTech and the R&D division of EDF, the CloudCompare project began in 2003 with the PhD of Daniel Girardeau-Montaut on Change detection on 3D geometric data.^[2] At that time, its main purpose was to quickly detect changes in 3D high density point clouds acquired with laser scanners in industrial facilities (such as power plants) or building sites.^[3] Afterwards it evolved towards a more general and advanced 3D data processing software. It is now an independent open source project and a free software.

CloudCompare provides a set of basic tools for manually editing and rendering 3D points clouds and triangular meshes. It also offers various advanced processing algorithms, among which methods for performing:

• projections (axis-based, cylinder or a cone unrolling, ..)
• registration (ICP, ..)
• distance computation (cloud-cloud or cloud-mesh the nearest neighbor distance, ..)
• statistics computation (spatial Chi-squared test, ..)
• segmentation (connected components labeling, front propagation based, ..)
• geometric features estimation (density, curvature, roughness, geological plane orientation, ..)

CloudCompare can handle unlimited scalar fields per point cloud on which various dedicated algorithms can be applied (smoothing, gradient evaluation, statistics, etc.). A dynamic color rendering system helps the user to visualize per-point scalar fields in an efficient way. Therefore, CloudCompare can also be used to visualize N-D data.

The user can interactively segment 3D entities (with a 2D polyline drawn on screen), interactively rotate/translate one or more entities relatively to the others, interactively pick single points or couples of points (to get the corresponding segment length) or triplets of points (to get the corresponding angle and plane normal). The latest version also supports the creation of 2D labels attached to points or rectangular areas annotations.

CloudCompare is available on Windows, Linux and Mac OS X platforms, for both 32 and 64 bits architectures. It is developed in C++ with Qt.

Input/Output[edit]

Forum Cloudcompare En Francais

CloudCompare supports input/output in the following formats:

• BIN (CloudCompare own binary format)
• ASCII cloud (one point per line 'X Y Z ..') [wizard]
• PLY cloud or mesh [wizard]
• OBJ mesh(es)
• VTK cloud or mesh
• STL mesh
• E57 (ASTM E2807 standard^[4]) clouds & calibrated images
• LAS and LAZ clouds
• Point Cloud Library PCD files
• FBX mesh
• SHP files
• OFF mesh (Geomview)
• PTX cloud (Leica)
• FLS/FWS cloud(s) (Faro)
• DP cloud(s) (DotProduct)
• RDB / RDBX / RDS cloud(s) (Riegl)
• PSZ projects (Photoscan)
• Various other polyline formats

Moreover, thanks to a collaboration with Pr. Irwin Scollar (creator of AirPhoto SE, a program for the geometric rectification of aerial images & orthophotos from multiple images), CloudCompare can also import Snavely's Bundler SfM software output file (.out) to generate orthorectified images (directly as image files or as 2D point clouds) and an approximated DTM (based on Bundler key-points) colored with images data.

Cloudcompare Command Line

CloudCompare can also import various other formats: AvevaPDMS '.mac' scripts (supported primitives: cylinder, plane, cone, torus, dish, box, snout and profile extrusion), SOI (from old Mensi Soisic scanners), PN, PV, POV, ICM, etc. Eventually, CloudCompare can also export Maya ASCII files (MA).

Plugins[edit]

A plugin mechanism enables further extension of CloudCompare capabilities. Two kinds of plugins are available:

• standard plugins for algorithms coming either from the academic world (ShadeVis,^[5] HPR,^[6] Poisson reconstruction,^[7] boolean operations on meshes,^[8] etc.) or from external libraries (PCL) or others (e.g. generation of animations with qAnimation)
• OpenGL plugins for advanced shaders (EyeDome Lighting,^[9]SSAO, etc.)

See also[edit]

References[edit]

1. ^CloudCompare v2.11.0 (Omnia) release
2. ^Détection de changement sur des données géométriques tridimensionnelles, D. Girardeau-Montaut, PhD manuscript (french), 2006 - available on Pastel
3. ^Change Detection on Points Cloud Data acquired with a Ground Laser Scanner, D. Girardeau-Montaut, M. Roux, R. Marc & G. Thibault, ISPRS Workshop Laser Scanning 2005, Enschede, the Netherlands, September 12–14, 2005
4. ^The ASTM E57 File Format for 3D Imaging Data Exchange, Daniel Huber, Proceedings of the SPIE Vol. 7864A, Electronics Imaging Science and Technology Conference (IS&T), 3D Imaging Metrology, January, 2011
5. ^ShadeVis an open source tool for computing ambient occlusion
6. ^Direct Visibility of Point Sets, Sagi KatzArchived 2012-06-06 at the Wayback Machine, Ayellet Tal, and Ronen Basri, SIGGRAPH 2007, ACM Transactions on Graphics, Volume 26, Issue 3, August 2007
7. ^Poisson Surface Reconstruction, M. Kazhdan, M. Bolitho, and H. Hoppe, Symposium on Geometry Processing, June 2006, pages 61--70
8. ^Cork Boolean/CSG library, Gilbert Bernstein, Stanford
9. ^Eye-Dome Lighting: a non-photorealistic shading technique, Kitware/The Source

External links[edit]

• Airphoto SE on the Bonn Archaeological Software Package project page
• Bundler project page
• OpenKinect project page
• libLAS project page
• libE57 project page