SCAN DATA FILE TYPES AND DEFINITIONS
Available export file options after processing raw scans:
Polygon- a mesh file consisting of multiple triangles and a normal vector that portray the objects shape. This is usually created as the first step in the scanning process. The final polygon file will be optimized and contains no holes. Polygon files are good for free form shapes and complex 3D geometry. They are imported into animation, rendering, and software that handle polygon files. Some CAM software programs can generate a CNC path from these files.
When to consider: Lowest cost, and used for animation & simulation. Many CAM programs can machine direct from these files. Good for free form shape models like sculptures or artwork.
Cons: Not compatible with most CAD software, large file size, and design changes can be difficult. Some geometry and features may not be perfect, no drawing output. Surfacing, rendering, and color need to be applied with other specialized software.
Surface model- generated from a polygon model. Surface models contain shape information that can be used in most CAD/CAM systems. This format is very useful for free form shape models with lots of curvature.
When to consider: Intermediate price, and great for free form models. CAM software can use the data to create toolpath for machining. CAD systems can import and work with a surface model, but may have limitations in editing or manipulating the data.
Cons: Surfaces are randomly generated, and often have limited editing capability in many CAD systems. Some geometry may not be perfect, limited dimension capability in drawings.
Feature based solid model- recreates the model similar to most solid modeling CAD programs. The difference lies in the fact that the input information is raw scan data, not manually created geometry.
When to consider: Best for mechanical style of parts. Model can be edited in most CAD systems.
Cons: More expensive due to time consuming process to create a finished model. Not recommended for free form models, some editing limitations in many CAD programs.
Parametric feature based solid model –includes the most comprehensive information such as design intent, dimensions, and a design history tree.
When to consider: When a fully editable model is needed in a native CAD format, and if future design changes are expected. These files preserve maximum flexibility for file exchange and machining options, as well as future design modifications. Complete documentation for 2D drawings and assembly documents. This is usually the best choice for “reverse engineering” of parts.
Cons: Time consuming to create, and therefore the most expensive design option. Native file format limited to CAD program it was designed on for file exchange with others.
PDF is widely used to send drawings and 3D model documents for clients to view and mark for revisions, but these files are not compatible for direct transfers into CAD systems.
Scan Formats Uses
Point Cloud Inspection (limited), export to specialized software for further processing.
Raw Mesh Inspection (full), export to specialized software for further processing.
STL 3D printing, images for documents, geometry replication with CNC, reference for further design.
IGES Basic- use if STL files are incompatible with machining software.
Precise- tooling for production, adding scanned surface to new design.
STEP Most common file exchange format between different CAD systems. Used for dimensioning, and shape/volume representation. Often used in an assembly to design around if changes to part is not anticipated.
As you can see, choosing the files you need is not always a simple process. Most projects will require a combination of file types to achieve desired output for each phase of a project.
Choice of appropriate file type for making parts is most dependent on:
Evaluating these four questions and making these decisions prior to starting a design leads to more accurate parts both for manufacturing and for visual representation, which saves time and money by not revising documents later in the design process. There might be 12 different ways to design a part for presentation, but only one way to accurately manufacture it economically.
WHAT DO I SEND SHOPS TO GET QUOTES?
To answer this frequently asked question properly, one needs to take a few things into consideration first. The files you may need to send can vary from one shop to another based on their software, equipment, capabilities, and type of fabrication. The files needed for a laser cut part will be different than the file needed if it is being 3D printed. Each phase of a project often requires files specific to that particular stage.
The best method is to contact each potential vendor and find out what they require. This gets you to the quoting stage faster, and generally a more accurate quote and timeline. If this isn’t possible, then the following process can get the job to the quotation stage.
1. Provide a 3D .pdf because anyone can open it and view the part without specialized software. Also send a 2D drawing in the .pdf format for the same reason, which provides general dimension or notes that are necessary for quoting. This gives the shop a good general overview of what needs to be done.
2. After the shop reviews these items, there are usually some additional questions or comments that require more details. Revisions can be made to the existing documents, or additional files may be necessary at this stage. Item specifics such as material, plating, GD&T, heat treating, or special processing may need to be discussed. Surface finishes, custom materials, flatness, and dimensioning standards all affect the quotation cost, as well as establishing what tooling, fixtures, and processes will be required to make the part.
3. At this point the specific files that are required can be generated, based on what the shop determines is best for them. Some shops prefer 2D dwg or dxf files, some need .iges or .stp files, others might need native CAD files, or even 3D models with embedded PMI information. Some CAM programs can create CNC files directly from mesh polygon files.
The shop will then generate all needed programming and tooling based on their equipment. Each shop will want to make the part their way, based on their experience and equipment needs or limitations. The machinist often has a specific approach that may not have been considered during design, or a more efficient way to complete fabrication.
If the CAM programming and tooling is a significant portion of the quote, you may want to consider dividing the quote into a non-recurring engineering fee, and a cost per part. The shop would charge one fee to program and create tooling, and charge a separate amount per part. Future orders will only incur the per part charge. Maintain ownership of the fixtures/tooling in case you want to have a different shop make parts in the future. Announcing that you intend to send the work to a different shop, and requesting the tooling used to make the part (if you don’t own it) never has a pleasant outcome.
MY .STL FILE ISN’T SCALED PROPERLY.
The first thing to be aware of is that STL files do not specify what units their distances are in. When a program opens a STL file, it only recognizes that the model measures a certain number of units in each dimension. These units might be meters, inches, kilometers, parsecs, or any other unit that exists.
The majority of 3D printing software uses millimeters for geometry, so it interprets STL files as having units of millimeters. These settings are usually set during initial installation of the software, but can be changed later.
If you are using software (like Blender) that uses arbitrary units, you must scale your model so that 1 unit equals 1 millimeter.
If you are using SolidWorks, or other software that designates its units, it is important to configure the export to use units of millimeters.
Here are two scenarios that are fairly common:
As you can see from the examples above, unit problems can cause the STL file to import smaller or larger than expected. This is corrected by scaling the model up or down by the conversion factor between millimeters and the exported units.
Our typical default settings for exporting stl files are:
I CAN’T OPEN A FILE.
Many 3D CAD files will only open on the specific software package it was designed on. We almost always include a neutral file format that can be opened by many different programs. Most of the major CAD packages offer free viewers that you can download, allowing you to view the file, but not offering any editing or printing functions. The links below are for the two most commonly used viewers:
Link for Adobe Acrobat DC free viewer- https://helpx.adobe.com/acrobat/using/displaying-3d-models-pdfs.html
Solidworks viewer- To download eDrawings, go to www.edrawings.com.
Instructions for using them are contained in help files included with the downloads.
HOW DO I SEND FILES?
Files up to 20Mb can generally be attached to an e-mail. Larger files can be sent via Dropbox with a link we provide.
|Software Company ||Best File Format|
|AutoCad, Inventor, Navisworks, Revit||DWF-3D|
|Microstation || .stp|
|NX|| .stp, .jt|
|ProE/Creo || Native .asm, Neutral .asm, .stp|
|Solid Edge ||Native .asm, .stp|
Many other 3D formats exist, but are not used as often or have specialized applications. All rendering and animation type files are from software packages that use different geometry, and will require extensive repairs, patching, and editing to create usable 3D CAD models or drawings. If you don’t have the above types available, send what you have and we can work on the best options. For anyone sending laser scan files or scan data, see the information below for those file types.
Common File Types
3D Print Formats
3D Neutral Formats
Precision Scanning & Design, LLC.
Please contact Precision Scanning & Design at your convenience for a free initial consultation. We’ll work with you one on one to determine a roadmap to success. We look forward to working with you soon.
Call Today: (813) 335-9486
WHAT FILES SHOULD I SEND?
Nothing is more important than sending the correct file types to save time and money opening and converting files. This is especially important when dealing with neutral file formats which often have missing geometry. The quality and accuracy of receiving the correct files can save time and money by reducing the editing and re-creating of a part. In theory it is simpler to open a part file and perform modifications to create the intended design, without any conversions.
To help understand the process, we need to define the two major categories of importing CAD files.
NATIVE: CAD files created in the same software package as the one the files will be edited with. For example- if the original files were created with Solidworks, we will use Solidworks to open and modify these files. Theoretically instant and accurate transfers make these files the best option.
Native file limitations- we can open older versions with newer software versions, but can’t open versions that are newer than the one we are using. For example- we can’t open a 2014 file with 2010. If we open a file with the 2015 version, when the file is saved it can only be opened with a 2015 or newer version. If you have a 2014 version, it will not open on your system.
NEUTRAL: CAD files developed to exchange between different software packages.
Neutral file limitations- very few types import perfectly, requiring manual editing of parts. There are numerous versions of many of these file types, and each can have unique problems with certain types of geometry exchanged between different software packages and versions. The files will need “clean up” before they can be imported and modifications can start with existing geometry in the file.
FILE TYPE PREFERENCES FOR SUBMITTING FILES
In order of preference:
1.Native Solidworks top level assembly (.sldasm) part (.sldprt) and drawing (.slddrw) files.
2016 through 2018 versions. Any others will be converted to one of these versions.
2.Neutral solid models, a STEP 214 file (.stp).
3.Neutral solids, a IGES [ Brep type 186] (.igs)
For surfaces or mixed with solids, a IGES [trimmed surface type 144] (.igs)
Many clients have a .dxf file or a .pdf document. We can open these, but they don’t import as a 3D model, and need to be manually built based on the provided dimensions. Following are some guidelines for other CAD software files: