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A beginers look at scanners.

Scanning equipment is a great benefit when the staircase has been made by a separate company to the handrail company.

When the staircase and handrail are all made “In house” it is very easy to work from the rod to draw the handrail components.

When working on existing staircases for repairs, preservation or even new build, when there is no rod available a survey of the staircase must be taken to be able to accurately produce or reproduce various components, including balustrades, spindles, handrails etc.

With digital scanning equipment, it Is much quicker to take an accurate survey, especially when working on spiral flights that are over many floors.

When working on spiral or elliptical flights it is normal to plumb down to the ground floor to get a 2D plan of the flight, This is required in order to work out the radius or springing points for the major and minor axis.

With digital scanning equipment, this can be easily done right in the software. Care must still be taken when carrying out the survey.

These scanners can also assist in the reproduction of many of the staircase components without having to dismantle the existing staircase.

Here we will have a quick look at how different scanners can be used for these various processes.

I will start with the two scanners I have access to and add more as I get the opportunity.

N.B.

This is my personal opinion as a handrailer or tradesman with basic knowledge of the different equipment and software.

There is no doubt better ways to use this equipment and software that I do not yet know.


Artec Eva

1.1 – Introduction.

The Artec Eva is a structured-light 3D scanner.

I have owned the Artec Eva for about a year now. When I first set it up I only had Version 9 of Artec Studio software and I tried this without much success. Things have certainly changed since then.

I now have Artec Studio 16, the difference is like night and day. I have used the scanner to scan a cast iron newel post for one of the visuals I was creating and it worked fantastically.

I still need to learn more about the software to get the models I am trying to achieve, but already I can see the potential in this style of scanner.

The data collected is considerable in size and a good computer is advantageous for processing speed, both during the scan and later during the scan processing.

Image courtesy of Artec 3D

1.2 – scanning stairs.

This is my first attempt at scanning a flight on site with the Artec Eva.

The staircase has marble goings and risers, which I thought might be a problem; due to the reflective nature of marble, however, the scanner seemed to pick up the veins in the marble and make a good scan.

The scan of the bottom 10 treads with stringers, risers and goings took about an hour to do, this was in 15 scans and then auto aligned with the autopilot function.

The image here is once autopilot has created the model and I have removed some of the unrequired bits of data.

Eva stair scan
Eva stair scan

Once I had the model, using Artec Studio’s scan-to-CAD features, I placed CAD shapes right over the model’s surfaces.

This lets you export CAD surfaces rather than only the 3D meshes.

This will be a much smaller file to work with but you may not have all the information you require, I have not yet found a way of referencing the surfaces in the Artec software to be able to accurately align any further surfaces I may decide to bring over into the CAD programme.

The other option is to export the complete model as an STL file.

This gives the full model in a mesh allowing for more control over creating the CAD plan views etc.

One thing I have noticed no matter which way you do it, it is that you need to be able to have a true plumb reference scanned with the staircase, as this allows for accurate positioning of the vertical and horizontal planes when working on the model.

More about this and further explanations of the different stages and the outcome in the full article on this scanner.

1.3 – Scanning newels, spindles and handrail parts.

Scanning of smaller parts of the staircase may be useful, especially in restoration work.

With traditional handrail geometry becoming a thing of the past it is useful to be able to scan the original handrail flow to get the correct geometry for the replacement parts.

This will then make it possible for the new parts to be produced by CNC machines.

See more about some of the differences between Tangent handrailing and CAD drawn handrail here.

The scanning of cast newels or carved components is ideal for reproduction or for visuals, I have used this for scanning a cast newel as in this image and a number of visuals throughout this site.

Cast Newel post
A cast Newel post 19/NP114 from different angles.

Full article showing the different stages of using the Artec Eva on its way.


Microscribe.

2.1 – Introduction.

The Microscribe although basic to some of the newer scanners available is a very simple scanner to use.

These scanners are classified as portable coordinate measuring machines. or (CMM) which work by relative positions contact on a surface or surfaces.

I have used the same Microscribe and software for about 14 years, so no doubt advances have been made in its technology but working on the theory of ” If it ain’t broke don’t fix it” I have stuck with it.

The scanner itself is very easy to use, the data collected is fairly clear with relatively small file sizes, this will depend on the techniques you use to scan and the reference points you take when setting up and carrying out the scan.

The Microscribe has to be set on to a stable surface or tripod whiles in use.

The software allows for the scanner to be moved and realigned with the previous scan data when scanning larger objects, an entire staircase can be scanned in this manner.

Image courtesy of Revware

2.2 – Scanning stairs.

Scanning stairs with the Microscribe is again fairly straightforward, the data captured can be easy to understand and work with.

As with any digital survey, there are a few basic principles to follow.

One of these is getting a true vertical and horizontal to be able to get the scan data orientated correctly before using it to create plans and elevations.

With the Microscribe and a laser level, this is quite easy to achieve.

Using the point on the arm and tracing it along riser and going joints or riser and underside of nosing the detail can be picked up to easily build surfaces.

There are additional tips or ends for the Microscribe arm, these can be used for following such things as core rail.

Scanning a full flight can be time consuming and keeping an eye on the alignment variation when moving the Microscribe from one position to the next is critical.

There are ways to take scan data that will allow for re-alignment back at the office if anything has moved a bit, I will go over this in the full article.

Microscribe scan data
Microscribe scan data of metal sub-frame.

With the scan data collected, surfaces can be added to construct the surfaces of the staircase.

Sometimes as in the image above (Microscribe scan data), it is not always possible to scan the creases or intersection between the treads and risers.

In these instances, I have found it best to get as much detail of the edge of each component and across the surface of each part.

This will give you as much information as you need to build each of the surfaces.

This was a scan of a metal subframe for a staircase that was to be clad in timber, not one tread in the entire flight was level, this is a good example of why to take horizontal and vertical references independent of the flight.

With the scan data used to build an accurate model of the substructure, the model of the finished flight can be built up over the top of it.

This flight was fully modelled and then sent to CNC for the treads risers and stringers, cut well strings and closed wall strings.

2.3 – Scanning newels and spindles.

Scanning of existing stair parts is pretty straightforward, especially if loose.

Timber spindles can be cut in half down the length, laid on a flat board and the tip of the scanner run around the outside of it, this gives a nice clean 2d outline from which to build the model.

When on site taking the pattern may be a bit harder but running a length of masking tape down the side of the newel or spindle and running the scanner point down this line will give a similar result, albeit only one side but a few scans around various points will allow you to mirror the one side over, giving the full size.

Handrails can be traced all around but do run a line or two along the length of the handrail to be able to align it in the cad software.

The timber spindle and handrail outlines documented in this site have all been scanned in this manner from original turnings etc.

Spindle plate 1 shaded
Spindle plate 1. Print this for your wall.

Full article showing the different stages of using the Revware Microscribe on its way.

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