Supplemental Design LLC offers 3D Scan to CAD and Scan to Model services for anyone needing 3D Scan Data converted to a 3D CAD Model. For example, if you received 3D Scan Data (such as a point cloud) from a customer, or if you’ve already had an object scanned and you need a CAD Model based on that scan data, Supplemental Design LLC is well equipped to process your scan data and deliver a CAD Model to satisfy your requirements. While Supplemental Design’s primary CAD program is PTC’s CREO (formerly known as Pro-Engineer), we also have Siemens NX, Catia and SolidWorks as well as a premier surfacing package named ICEM Surf. We can also provide IGES and STEP files that can be imported into your CAD program. Depending on the object’s geometry as well as some of our software’s capabilities, it might be best, or possibly necessary to supply an IGES file as the deliverable. This can most likely be determined early in the process once the customer has communicated their wishes and Supplemental Design has become familiar with the object’s geometry. With complex models, it is fairly common to have some non-parametric surfaces in the model. Supplemental Design LLC is not limited to the capabilities of just one Scan to CAD program, we can utilize the one that best suits the needs of each specific part or project. If you’re interested in using Supplemental Design LLC for your 3D Scan to CAD/Model needs, please share your project needs by completing the Contact Form or send an email to inquiries@supplemental-design.com.
ABOUT SCAN TO MODEL SERVICES AND OUR PROCESS
One of the biggest challenges encountered when converting physical objects to digital is the incompatibility among the different types of 3D models, solids, surfaces, meshes, and point clouds. Point clouds and meshes are the output of 3D scanners and the format most commonly understood by 3D printers is the mesh file, often times .stl files. A mesh represents the surfaces of a part with a large number of triangles established by three scan points, connected edge to edge.
Physical to Digital:
The very first step usually involves some processing of the mesh, meaning filling holes, possibly defeaturing it, as well as refining the mesh in various ways. During the next step, the Scan Data obtained from the real world, as manufactured part, is referenced in order to create the CAD Model. Geometric shapes are extracted from the mesh, obtaining flat surfaces (planes), cylinders, cones, as well as complex surfaces. Additionally other references can be extracted as well, such as points or axes defining locations of features such as holes, as well as cross-sections and profiles, all of which are referenced to create the requested deliverable.
Deliverables:
While there are multiple deliverable options for customers, they may not always be clear. Generally, the point cloud or mesh is unusable for a customer’s needs and purposes. As a result, customers may believe something more or possibly less is needed than what really is. They might believe they want a fully parametric model, when in fact, the cost might be greater than the value they obtain. This is where Supplemental Design LLC can potentially assist and make suggestions if the geometry and our various software’s impact the decision. We’ll begin by asking the customer the below questions.
- Will the model provided be used simply as a reference so the customer’s design will fit and fasten to it, or will formed parts intended to provide a sealed or mated fit be part of that design?
- Many times, customers may only need the surface, such as contoured surfaces of a vehicle. Will that surface need to be able to be offset? Is that a requirement or is it even a practical objective? This is a very important criteria to know from the beginning of the project in order to meet the client’s needs. Some complex surfaces with small radii can’t be offset without the use of additional modeling techniques. This would normally be done by the customer’s designers due to unknown offset values that may come up during their design process.
- Will this model or deliverable be used primarily for display purposes? For example, will it be used simply to display the customer’s design on or near it, or to show that a hole or other modifications will need to be made to it in drawings or possibly in an assembly model? If that’s the case, usually an exterior or interior surface of the part or parts will often be satisfactory, unless there are some additional requirements.
- Would an automatically created surface, which is much quicker and more affordable, suffice? It should be noted that there are some inconveniences with automatically created surfaces, they normally consist of a high number of small patches to create an accurate replication of the surface. That means there are lots of tangent lines and edges between those patches which, depending on CAD software, can be difficult to deal with in drawings and possibly undesirable in assembly models. This can also be problematic if offsetting the surface is, or becomes necessary.
- Is a model with mass properties required? If so, surfaces won’t suffice, so the customer will need a solid CAD model. If it’s another supplier’s part, or a customer provided part that the customer won’t be revising, then an IGES or STP file is probably all that will be needed. Since many CAD programs include some form of direct modeling, even an imported IGES or STP file can be modified with some limitations.
- How should the referenced object’s scan data be utilized while creating the model? Many read the 3D Scanner’s specifications and see the high accuracy that’s declared. Many companies offering scanning services and Scan to Model services talk about providing “perfect” models from the scan data. Please realize that a singular, imperfect part has been scanned, just how perfect is that part compared to the manufacturing drawings or for that matter, the tolerances allowed? Another unknown is how accurately the part was inspected during their quality control process, if at all. Many manufacturers don’t like to discard parts, so you never know just how close the scanned object is to perfect or even acceptable. Then there’s plastic parts, which often have some warpage and shrinkage, and if the part is flexible, it might be important to consider dimensional variations introduced by the part being scanned in free state rather than its fixed state.
- Once the scan data is brought into a Scan to CAD program for further processing, the operator usually selects the best flat surface to establish an A Datum, type of plane. If there are cylindrical or conical features that a theoretical B Datum Axis can be based on, that will often be referenced, or another planar surface, and then another feature to extract for a good orientation Datum to use. None of these will be absolutely perfect; they might be very close, but absolute perfection is unrealistic. While the actual Datum structure can always be different than the selection to orient the mesh in the model, Supplemental Design would like to know if the customer has any preferences, especially for Datum A, from which most every feature will inherit its orientation. The customer will usually have at least some familiarity with how the part mates up or is mated up to.
- Obvious flaws, such as damaged, broken, or worn areas on a part, will need to be fixed, however other manufacturing defects fall into gray areas. Therefore, it’s important to know if the customer wants manufacturing defects corrected, such as core shift, sink, shrink, warpage, flash, parting line, dam, sprue, gate or injector pin artifacts. If the part is cast, molded or forged, it will have manufacturing features, primarily parting lines and draft. We will need to know if these features should or shouldn’t be preserved, the customer may have plans to use other processes such as additive manufacturing or machining and may not want to duplicate the manufacturing features. If that is the case, Supplemental Design will need to know if they want to add or remove material. Many times, the application or assembly the part fits into, as well as clearances, will determine this. When determining to add or remove material, please be aware that it may adversely affect the part’s strength, especially if FEA Analysis was done on the part. If the part was sent to the manufacturer without manufacturing features, it can be difficult to know if material was added or removed as they applied draft and established parting lines. In addition, we’ll ask if there are design modifications that should be implemented.
Once these facts are clearly understood, questions asked and answered and requirements have been communicated, it is then possible to determine the deliverable that will best fit the client’s requirements, as well as any accommodations that might be needed while scanning the object. The results of 3D Scanning run along a spectrum of relatively simple to extremely complex models. The cost, time, as well as the level of communication required, increases along with the complexity of the desired results.
If a customer’s requirements aren’t explicit, the Designer may attempt to make an educated guess based on experience as to what areas are kept “as-built” and which are corrected to assumed “design intent.” On simple shapes, such as flat surfaces and straight edges, this is not difficult to determine. For example, if a cube designed with 6” sides, has a 6.01” side, then correcting the length to 6” is simple. One can also generally assume that the sides should be parallel and perpendicular to one another, with the exception of draft. However, as complexity of the part increases, assumptions of “design intent” also increases exponentially. Consequently, the designer won’t necessarily be able to decide what is correct in the eyes of the client, and what is not. Mounting and mating may make some dimensions of the part critical to its fit in an assembly, so mating part information may be required. Therefore, it’s critical we have the customer’s detailed instructions.
After considering the above, we return to the issue of how best to utilize the Scan Data while creating the model of the part. If we have faith in the accuracy ratings for the 3D Scanner, the customer may prefer to limit assumptions and use the actual geometry extracted from the Scan Data, this is also a faster method, so it’s also less costly. If a cylinder or a flat surface obtained isn’t perfectly perpendicular, will they want to use the data extracted from the “highly accurate” 3D Scanner, or should the designer make potentially erroneous assumptions by straightening it and guessing where exactly to locate it? If the features are mating surfaces or fastening locations the location will probably be rather critical, so Supplemental Design will need to know if other components are driving their locations. Many times, the customer is using the part in their design and will reference the scan part’s fastening locations to establish their mounting provisions using tolerance stackups so it will always fit. If they have or can get drawings or specifications, such as hole sizes and locations, they should supply that information so the information can be utilized while reconstructing the part.
Supplemental Design LLC requests this rather “theoretical” preference from clients so we can provide the results they prefer to have, rather than forcing an opinion on the client that they may not prefer. If the customer has some deviation requirements or expectations, they must communicate those expectations prior to beginning the work.
It is the customer’s responsibility to review all deliverables prior to utilizing it or incurring additional costs. Supplemental Design LLC will supply a report describing the deviation of the model from the scan data to aid in their review, but their review must include opening and examining the model for any potential issues, including model issues due to feature failures or translation errors. Some deviations do occur and are expected, absolute perfection is virtually impossible. Supplemental Design LLC, as well as the customer the work is being done for, want the best possible results with the least amount of deviation or issues. Supplemental Design LLC will make every reasonable effort to work with the customer until they are satisfied that the deliverable meets their needs, but their expectations need to be clearly communicated early in the process.
