Frequently Asked Questions
What is 3D Scanning?
3D Scanning is a method of recreating the surface of an object by using either whitelight scanning or laser scanning technology to take many points of measurement along a surface. These millions or thousands of points of measurements are called a point cloud and are the base for recreating a surface of an object. The more points of measurements gathered (or the more dense the point cloud), the more accurate the overall recreation of an object.
What is white light scanning?
White light scanning is also known as Structured Light scanning and is a 3d scanning process using a non-contact structure white light pattern projected on the object. The sensor of the scanner which is equipped with two cameras take several images of the part during the measurement and advanced image software calculates point co-ordinates from multiple images with the projected pattern. Unlike contact scanning, white light scanning arbitrarily designates the point co-ordinates of the surface being scanned. For scanning parts with several scans, several such measurements are carried out and merged together with the help of markers fixed on the part.
What is the difference between White light and 3D Laser Scanning?
White Light scanning systems projects light patterns on an object and two cameras simultaneously capture images. Then advanced software algorithms triangulate and calculate 3d-coordinates of millions of points on the surface of the part thereby recreating the surface. Laser systems use a projected laser light and complex mathematical calculations to measure the time/distance it takes for the laser light photons to reflect off the object and return back to the scanner sensor. White Light Scanning is the optical 3D Scanning method preferred by most industries because it offers precise, reliable and accurate results.
What are the output files of 3D whitelight or laser scanning?
The output of scanning is a dense point cloud or triangulated stl. This output can then be exported as IGES, VDA, ASCII or STL format.
How can 3D Scanning improve my workflow?
The purpose of 3D Scanning is used to: recreate or modify an object (reverse engineering), rebuild a duplicate object, or to verify a manufactured object’s proportions with the original design or CAD file (inspection). The process can be done with a wide variety of equipment ranging from 3D whitelight and 3D laser scanners that generate thousands of highly accurate points of measure per second. In a nutshell, its fast and accurate!
What is Reverse Engineering?
Reverse Engineering is a term used to describe a process of generating engineering or manufacturing measurements and surface parameters from an existing product or object. The process of Reverse Engineering follows this typical workflow:
- 3D Scanning / White light Scanning (point cloud generation)
- Surfacing of point cloud data and/or Data Clean up
- Solid Modeling or CAD
What is Photogrammetry?
Photogrammetry is a co-ordinate measuring technique to generate 3D-co-ordinates of points & features from a group of photographs taken from different points in space. This science is being used to calculate the precise 3D co-ordinates of industrial parts ranging in size from a few mm to as large as 50 m (or more).
In order to get a better accuracy in scanning process many software packages incorporate photogrammetry. This enhances the accuracy of merging scan data from multiple shots, especially when scanning a large object in the marine, automotive and aerospace industries.
Why is surfacing required after scanning?
Surfacing is a process of fitting surfaces onto point cloud data ensuring specified tolerances. Surfacing is required in order to use the scan data for machining smooth surfaces mainly for die or mould production, inspection or packaging purposes. Surfacing that involves the maximum amount of smoothness is considered a Class A surface and is commonly used in the automotive industry.
What is a Class A surface
The definition of class A surface is always a point of contention but the definition is, “a surface that conforms to a set of tolerances for continuity to surrounding surfaces and smoothness within the surface”. Class A surfaces will be subject to “Reflex” in which light shining on a surface may show imperfections in the surface. It is virtually impossible to transition directly from scanned data to class A surfaces. Generally the scanned surfaces serve as a reference for comparison to Class A modeled surfaces.
Can machining be done with raw point cloud data?
Yes it is possible to do machining on point cloud, for some applications. However this is usually not ideal. Manufacturing moulds, dies, where tolerances are high, or where clean surfaces are required, you will need an intermediate process of Surface & Solid modeling based on the point cloud data.
What format of surface or solid model is available?
This is dependant on the finished goal of the project, whether or not revisions to the file is required, or what type of manufacturing process will be used. We can provide surfaces either as dumb solids or with fully editable feature trees. We can provide surfaces and solid models in native formats of various software such as UniGraphics, Ideas, ICEM, Rhino, Solidworks or Pro-engineer. Output formats can also be neutral formats such as IGES, Step, VDA, Parasolid, etc.
What format of surface or solid model do I need?
There are 3 process output file types for scan data, to determine which one will suit your needs depends on what you plan on doing with the 3d scanning and CAD data.
1. Wrap Surface Model
Refers to the way in which 3D scanning software like Geomagic, RapidForm, and Paraform fit IGES surfaces to a "physical" scan. Similar to how plastic shrinkwrap "shrinks" down onto a part being "wrapped". This is a fast way to resurface a part but has the disadvantage of including scan imperfections, and cannot be edited. This method is very useful for organic shapes such as the complex curves of a vase or water jug.
- Captures as-built state
- Includes manufacturing defects
- Patch-work of small surfaces
- Non Class A model
2. Hybrid Surface Moldel
This is a very common CNC machining file requirement and is usually an IGES or STEP surface that may combine auto-surfaced features with 3D modeling operations. Hybrid models are also "dumb" because the data contains design history of the model. Such models have areas that are instead are composed of NURBS surface estimates of the scan data.
- Ideal data converted from scan data
- Can ignore or incorporate manufacturing defects
- Modifications require additional time to resurface
- Can be Class A surfaced
3. Parametric Model
A model made up of data sets that retain the history of how it was designed (also known as a feature tree), so that modifications to one prtion of the model will update all downstream features. Exchange of such models is supported by IGES. SolidWorks, Catia, ICEM and Unigraphics are software programs that are commonly used for creating and modifying parametric models.
- Optimized modeled data from scan data
- Ideal for editing and design
- Modify model parametrically
- Can be Class A surfaced
Workflow
1. SCAN AND GENERATE POLYGONS
Integrated with major 3D scanning platforms, Geomagic Studio and Rapidform provides powerful point cloud processing tools to create polygon meshes. The STL file is created from the scanner and is a series of triangles. It can be CNC machined from but not edited.
2. EDIT POLYGONAL MESH
Interactive polygonal editing tools provide the control and flexibility to sculpt and reshape models during the 3D modeling process.
3. CREATE SURFACES
Create optimized wrap files autogenerated using the by the computer software and attempts to match the surface as specified or parametric CAD models, complete with feature trees that are editable within commonly used mechanical CAD packages.
4. CREATE EXACT SURFACES
Exact surface modeling is the preferred method for creating highly accurate 3D replicas of an existing object for analysis, scientific and medical applications.
Contact Us with questions on how we can help you
