6 reasons: When to choose 3D Scanning

3D scanning is a fast way to put a real-world object onto a computer in 3 dimensions. On the surface of things it seems easy, but the reality is a little more complex and knowing when to use 3D scanning is a skill in itself. The purpose of this article is to help you understand when it is good to make that call.

There are plenty of articles on how 3D scanners work and the different types of 3D scanners, and I really just wanted to tackle why and when you should choose 3D scanning over traditional CAD creation.

Ultimately the driving force behind a decision to choose 3D scanning is either because it's cheaper than the alternative, it's quicker or it simply cannot be matched by quality. The sweet spot for a customer is all three reasons. Let's get started:

1. The object has complex, compound, curved surfaces

A compound surface curves in more than one direction at one time. To better explain what a compound curve is, it is better to show what it isn't! See the cyclinder below - it curves along only one axis, or in one direction. This means if I can measure the diameter of the cylinder (D) I can create the straight sided cylinder with the curve (C) running along the same axis - and I can do this in computer software.

Basic geometry like this is quick in CAD software so the only time you generally would need to 3D scan a cylinder (or similarly simple geometry) is to check the quality and consistency as it comes off the production line at the manufacturing stage i.e. are there any deformities?

When a surface curves in more than one direction, unless it is a geometric shape like a sphere it becomes more complicated to recreate in software. Think of a car wing, a person's face or bicycle seat. They each have very complex shapes and curves and to try to recreate them accurately is almost impossible - certainly when comparing time and cost. This is where 3D scanning comes into its own.

2. If accuracy is important to you

Often clients wrestle with this one. It is difficult to know exactly how inaccurate the alternative process will be and it can be easy to persuade yourself that the alternative process will deliver what you need.

Let's go back to the wing mirror (see image below) and imagine it needs to be redesigned. You have the original, and you'd like to give it to your CAD designer to recreate the object in the CAD software. Will it be possible within a set time and budget? Can they match the accuracy of all the curves and edges? Will it fit the car?

With something as complex as a wing mirror the answer is no, and 3D scanning is the only choice in this situation. 3D Scanning with around +/-0.1mm will be more accurate than a person can measure and recreate in CAD - especially in any given timeframe.

The way to think about it is like this: The designer needs to be able to physically measure the curves of the real wing mirror and recreate them in the software. However there simply is no tool with the capability of doing this other than a 3D scanner. Additionally the beauty of a 3D scanner is that you not only gather curves and measurements but you can quickly gather data such as volume and surface area as well.

3. You want an exact mirror of an original part

We often have customers asking for 3D scanning of an antique car part - a door handle or similar feature, so it can be simply mirrored ready for production to fit to the other side of the car.

3D scanning in this situation avoids the only other option of trying to accurately copy an object with compound curves (as in 1&2 above) which needs to fit to an existing curved surface. Thus 3D scanning becomes a very economical way forward by comparison.
There is also the added benefit that the 3D file can be stored for future use for either left or right hand side, future-proofing the part.

You can see a case study of an indicator cover we 3D scanned for just this purpose here.

3D Scan of an indicator cover we mirrored for the customer (including resetting the text).

4. You need to archive an original object (art or heritage)

If you need to archive an original object, there really is no sensible alternative to 3D scanning. Attempting to recreate it in CAD is only an interpretive copy. Whereas a 3D scan is an accurate 3-dimensional record of the object in question, including texture if necessary (texture being the colour information of the object).

What about making a mould? Yes making a silicone mould is an option however the downsides are too numerous to make it a viable solution - [1] potential damage to the original is a possibility, especially if the object is porous as the silicone is designed to get into every crevice. [2] It costs more to make good silicone moulds. [3] Moulds deteriorate over time whereas a 3D files do not. [4] It takes significantly longer to create silicone moulds. [5] Texture (colour information) can be captured with 3D scanning but not with mouldmaking. [6] The additional benefits of 3D scanning are amazing: The ability to use the 3D files in virtual reality / 3D warehouses online, to be able to 3D print educational copies, to investigate production processes or analyze attributes of the digital object without damaging the original.

Ultimately if the shape is complex there is no other way of capturing such a rich amount of information as quickly and effectively.

5. You want to capture the texture (colour information)

There is no quick substitute for this one. The 3D scanner captures the texture detail (ours up to 300dpi) at the time of the 3D scan so 3D scanning has an almighty head start over attempting to recreate the texture afterwards by hand in software. It is dependent on the object and level of detail though. If you wanted a relatively simple and forgiving object like a banana 3D scanned, the texture would be quite quick to recreate in computer software so it could be a similar time / cost to create the banana with texture from scratch in 3D software or 3D scan.

However a pineapple...no chance!

6. There is simply too much detail

Sometimes it just comes down to the amount of detail in the object. Take this rusty old shovel. It is a fairly complex shape to make and it has lots of surface detail. Even if you didn't need texturing it would be a close call to exactly recreate in the same timeframe as 3D scanning. However going back to no.2 above for a moment, if accuracy is not important it could be cheaper to build a close replica from scratch in the 3D software. Sometimes it is a really close call which way to go, and you should discuss with your chosen 3D scanning service.

6. You can't touch or work on the original object

Because 3D scanning is non-invasive and non-destructive, it can be used for the 3D scanning of fragile, ancient objects and art that cannot be allowed to be moulded or handled in any way. Again there is no alternative for the archiving or duplication of this type of object.

That's my list. Remember 3D scanning is not a magical solution to all data capture projects, but an important part of the process. Use the summary below to give you a head start when deciding whether 3D scanning is the right solution for you.

Quick Summary

1.  Does the object have complex, compound curves? If yes you should seriously consider 3D scanning
2.  How important is accuracy? If it is important to you, 3D scanning is the right choice.
3.  Do you want to mirror an existing part? If so 3D scanning is the way to go.
4.  Do you need to archive an original object or artifact? If yes there is only one answer: 3D scanning.
5.  Is capturing the colour information important to you? It is impossible to recreate any kind of complex colour information as quickly and economically as 3D scanning.
6.  Is the object extremely detailed? If so it will be much quicker to 3D scan than recreate from scratch in computer software.
7.  Is the object too fragile or valuable to risk getting damaged by a moulding process? If so 3D scanning is non-invasive and non-destructive and the only way to go.

This list is not exhaustive but should help give you a little direction. Always the best choice is to contact your chosen 3D scanning service to check whether 3D scanning is the best way forward for your project.

info@chinchilla3d.com  www.chinchilla3d.com