3D Data 3D Point Clouds, Points, Drawings and Models

3D data.. what do I need?

If you are not 100% certain exactly which type of 3D data you then this short guide should help you. If you need any further help then call us on 01905 622495 and one of our survey team will talk through your requirements with you.

Point cloud

A point cloud consists of many millions (and very often billions) of 3D points usually collected by using a laser scanner, or sometimes from using photographic techniques. File sizes are usually very large - often many Gigabytes in size. They can be brought into AutoCad, Revit, Microstation, and some other CAD or BIM software suites and can be used as a reference to create drawings or models from. Each point has an x,y and z coordinate and usually a reflective value (this represents how light or dark the surface is that the point has measured to - imagine a black and white photograph), and sometimes a colour value too.

To handle point clouds well, a powerful computer is required, preferably with at least 16 Gb of RAM. To draw or model effectively from a point cloud additional 3rd party software is usually also used to edit and manipulate the data.

Because of its size a point cloud file is usually delivered to the client on a USB memory drive.

3D points file

A 3D points file is a text file that can be in a number of different formats depending on what software it needs importing into. Usually it consists of an x,y and z coordinate for each point with other information attached such as an identifying number and an identifying code (eg a kerb line might have a code KB or a spot height will be SH). Other attribute information can also be attached to each point. 3D point files are usually used to show the topographical surface and features on a site. When imported into a program like Revit they can be modelled to represent the ground surface.

A 3D points file is usually quite small and can be delivered as an email attachment.

3D CAD drawing

Topographical surveys are often shown as a series of flat, 2D lines and 2D points and symbols in a 2D CAD drawing, but topographical information can also be provided as a 3D drawing. When a 3D CAD output is required every line, point and symbol in the drawing will have an x,y and z coordinate and the drawing can easily be interrogated for height information or imported into specialist ground modelling software to aid the design process.

File sizes are usually a few Mb in size and are often delivered as a zipped email attachment.

3D model

A 3D model can consist of solid objects, surfaces only, a wire frame, a fully parametric Building Information Model, or a combination of any of those formats. Typically, models are delivered in major CAD formats such as DWG or DGN, as a Revit BIM in RVT or IFC format, or as a Sketchup model.

Models vary in size, depending on requirements and are typically delivered via an online service such as Dropbox.