Wednesday, 28 August 2013

The Making of Kitschpot

Kitschpot was designed by Adam Nathaniel Furman for the Designers in Residence programme exhibition at the Design Museum, 2013. 

3D printed Kitschpot

The original file is modeled and textured in Rhino version 5 and exported to VRML format. At Lee 3D we opened the file in Magics for checking before 3D printing on the ZPrinter 650 colour 3D printer.
Part sanded sitting on the 3D printer

Two sets were made. One was rubbed down and sent to CP Ceramics where a mould was made ready for slip casting the forms. 

As a 3D printer this image really appeals to me. Parts that come out of the printer are covered in plaster powder and need time to be revealed. These cast parts come out so clean and crisp it must be a joy to work with this process.

Slip cast Kitschpot still in the mould 

After firing, the cast forms have shrunk, which is a normal part of the ceramics process. The 3D printed pattern bears the mould makers marks used to ensure that the moulds will part easily and releasing the cast forms. The colour in the patterns is permanently faded by now, probably indicating the parts were wetted at some point in the mould making process. 

The Kitschpot pattern with offspring

Another attraction to casting from 3D prints is that many parts can be produces form a single mould.

Kitschpots sitting around waiting for glazing

The exhibition of 3D printed forms designed by Adam Nathaniel Furman will be on display at the Design Museum,  from 4 September until 12 January 2014.

To find out more about 3D printing at Lee 3D visit

Monday, 26 August 2013

3D Printing for AEC – Both Feet on the Ground

For some years, those of us working in the field could sense that 3D printing was ready to metaphorically explode.  This was based on the fact that very few people actually knew of 3D printing and people’s reaction when first introduced to it was often one of wonder and amazement.  Working predominantly in the field of 3D printing for Architecture, Engineering and Construction (AEC) we naturally and perhaps naively assumed that when the boom in 3D printing came there would be a similar step change in 3D printing for AEC.

We were wrong.  The boom in 3D printing was a boom in consumer 3D printing that has unleashed the imagination if not unleashed the realities.  3D printing for AEC has steadily grown since 2005 when the Spectrum 510 (ZPrinter) was unveiled.  The 510 printed at 600 x 540 dpi with a layer thickness of 0.1mm.  It enabled us to create architectural maquettes overnight to a standard that professionals were willing to accept.

Since the first consumer 3D printer was made in 2007 by the RepRap project, there has been an exponential growth in both sales and manufacturers of these machines matched by media interest and hype.

At the same time, use of 3D printing in AEC has grown steadily but in no way exponentially.  So what is the continued growth in 3D printing in AEC actually linked to? Some factors that influence uptake of 3D printing are:

  • Improvements in technology
  • Cost
  • Increased use of 3D software tools
  • Increased competition
  • Greater awareness

Improvements in Technology
The technology most used for making building maquettes is the ZPrinter.  SLA and SLS are also largely used but usually by model makers.  FDM has never produced a good enough surface finish, while the Objet has remained too expensive and not quite up to the mark set by SLA.  SLS and SLA have hardly improved in the past 10 years both having been around for 20 years or more.

The ZPrinter technology has a variety of advantages; being quick, relatively low cost, aesthetically acceptable, full colour and easily accessible by small niche bureaus willing to spend time preparing architectural data.  Architects wanting multiple concept models at short notice make use of the speed of the technology, master planners make use of simple colouring for indicating zones, construction professionals use colour for indicating different materials or trades in a programming model.

Eight years after the Spectrum 510, the latest best in class ZPrinter (now a called a Projet by the current owners of the manufacturer) still prints at 600 x 540 dpi with a layer thickness of 0.1mm and though there have been significant steps made in raw strength and colour, the technology itself is essentially static.  This is evident in the number of 510s still in use in bureaus producing white models that are no different to the parts printed in the most up to date machine available today. 

Steady improvements in technology are consistent with the steady increase in use of the technology in AEC.

In London, bureau prices for 3D printing have remained fairly stable over the past 8 years.  Manufacturer prices have risen significantly and bureaus have frozen prices by hollowing larger models to a greater extent as the material raw strength has allowed.  Personally I began hollowing models as soon as I had software capable of doing so to make more projects viable to 3D print.

Meanwhile for those companies buying the machines for use in-house, the capital costs and consumables costs have risen.  Companies buying 3D printers have rarely bought software that enables them to efficiently hollow models and this combined with lack of internal demand it is likely that for most low use companies the cost of printing in-house is higher than that of using bureaus.

SLS prices have become more competitive with increased global capacity and the commodification of machine space. But this is still a four to five day process that most AEC professionals do not have, most of the time.

It is therefore difficult to make any case for cost influencing increased use of 3D print in AEC.
I should add a note here that competition with traditionally made models does have a part to play though not a large one.  3D printing can show geometry, some colour and can indicate surface textures but it really cannot compete with traditional models that show actual materials such as wood and steel.  3D prints can be less expensive than traditional models but as they serve a different purpose the overall effect is small.

Increased Use of 3D Software
In 2005 there were very few architectural practices with more than one or two 3D modelling specialists who were usually engaged in visualisations for early stage design work and competition work.  Most high end visualisations were outsourced and probably still are. Increased use of 3D software in university departments with 3D printers has underpinned the steady increase in use of 3D printing in architecture.

SketchUp has been around since 2000 and is one of the most widely used modelling tools for making AEC 3D printed models.  The reason for this is that it is good for making initial design models at a stage in the design process where 3D printing has most value in developing designs and as a communication tool in persuading clients.  Nobody can pretend that SketchUp is a tool made for 3D printing.  Often SketchUp models are difficult and time consuming to prepare but their very existence has contributed enormously to the number of 3D printed models made.  The question remains, has there really been increased use of SketchUp over the past 8 years?

BIM has long been seen by the 3D printing community as a double edged sword.  Because BIM is a fully 3D environment it creates favourable conditions in which 3D printing can thrive, but BIM models suffer from a need for editing.  The first kind of editing is where details are not resolved. It seems to be in the nature of BIM models that where construction details are unresolved, parts are left floating in space.  Someone needs go through the entire model and make mullions, cladding and structural elements touch so that the 3D printed model does not fall apart.  The second kind of editing that needs to be done is to remove information that is not relevant to the model.  3D printing at scale, BIM models are notorious for containing pointless information.  Doors with hinges and screws and the manufacturer’s name pressed into the hinge would not be an exaggeration.  At 1:500 a 50mm door needs to be thickened from 0.1mm to 1mm and we do not have any place in the file for ironmongery.

However the use of BIM has created roles throughout the construction industry that require professionals to work in 3D.  This has to be good for the future of 3D printing but perhaps has not had a significant effect in the past.

There has undoubtedly been an increase in use of 3D software and this has probably had an effect on increasing the amount of 3D prints made.

Increased Competition
With the downturn in the economy that occurred in the late 2000s, winning scarce jobs undoubtedly stimulated increased use of 3D prints to help bid teams to win new work.
Similarly reduced numbers in architectural practices led increased outsourcing of sketch models.

At the same time there has been less work about and consequently less money for experimentation and non-essentials.

In London, the increase in the number of bureaus offering 3D printed models has led to a greater number of industry professionals trying out the process.  This is not quite the same as the number of businesses becoming repeat customers and incorporating 3D printing into their workflow.

Increased competition has led to an increase in the number of 3D printed models being made.

Greater Awareness
As a consequence of intense media hype and a proliferation of 3D print based companies there are not many individuals that have not now heard of this miraculous new process.

It is often observable that when a project involves a 3D Print at an early stage, 3D printing is used extensively throughout.  My reading of this is that when developers see 3D prints they encourage their use. In many ways it is developers that will be responsible for demanding 3D prints.  I have written previously about the ability of 3D printing to democratise design communication and it is usually in the interests of developers to have their projects communicated clearly and to the widest possible audience.

Greater awareness has led to a wide range of customer expectations of what is possible and also is certainly responsible for increased use of 3D printing in AEC.

The real work that needs to be done in order to incorporate 3D printing into the AEC workflow is challenging.  One often needs to remind oneself that the Sydney Opera House was built not just without 3D printing but without the CAD packages we are used to today (computers were used for structural analysis). Architects have been designing buildings for many years without the need for 3D printing or CAD or BIM or computers.

However all of these tools have advantages that generally outweigh the disadvantages.  The fact is that 3D printing is not needed for all stages of every project.  In fact some projects just do not need 3D printing and never will.  There are many reasons for 3D printing to be used between conceiving and selling a completed building to its end user and it is for architects, engineers and construction professionals and all of the conditions listed above to be right in order for use of 3D printing to grow.

So amid the intense hype surrounding 3D printing we need to keep our feet firmly on the ground and keep making models that serve a purpose in bringing buildings to completion.

For more information on 3D printing for AEC visit

Tuesday, 13 August 2013

Anatomy of an STL File

Quick Summary of main points on this post:

  • STL files desicribe a mesh of triangles with no other information.
  • STL files to not contain unit information
  • STL files do not contain colour information*
  • Some applications always export STL files in feet or inches
  • 2 types of STL file - Always choose Binary as it makes smaller files.

STL is sometimes called Stereolithography Format or more properly Standard Tessellation Language. It has become the default file format for many single colour 3D printing applications. It was developed by Chuck Hull soon after he built the first 3D printer and the first specification was released in 1988.

Below is an example of the contents of an ASCII STL file that partially describes a cube drawn with one corner at the origin and with sides of length 1 unit. It is worth pointing out that there are two types of file STL format: binary and ASCII. They contain exactly the same information but the ASCII files will be much larger as they contain human readable text while the binary file is essentially a compressed version.

It can be seen that the contents of the STL file is very simple, it is essentially a list of coordinates that describe triangles and the normal that describes which direction each triangle faces. STL files describe a mesh of triangles with no other information. When exporting STL files, vector and nurbs based software may ask for a tolerance which is used to calculate how many triangles are needed to describe curved surfaces. Generally, the lower the tolerance the closer the triangles match the curve of the geometry and the more are required to create the form and so the large the file becomes.

One important thing to understand about an STL file is that it does not contain any information on what units are being used. The units used in any particular file will be determined by the software that was used to export the STL file. Usually the units will reflect the units that were used to model the geometry so if the model was modelled in meters the units will be meters, if the model was modelled in mm the units will be mm. However some software and export plugins that were written in the US may default all exported STL files to inches or possibly even feet.

  facet normal -1.000000e+000 -0.000000e+000 -0.000000e+000
    outer loop
      vertex 0.000000e+000 0.000000e+000 1.000000e+000
      vertex 0.000000e+000 1.000000e+000 1.000000e+000
      vertex 0.000000e+000 1.000000e+000 0.000000e+000
  facet normal -1.000000e+000 0.000000e+000 0.000000e+000
    outer loop
      vertex 0.000000e+000 1.000000e+000 0.000000e+000
      vertex 0.000000e+000 0.000000e+000 0.000000e+000
      vertex 0.000000e+000 0.000000e+000 1.000000e+000
  facet normal 0.000000e+000 1.000000e+000 0.000000e+000
    outer loop
      vertex 0.000000e+000 1.000000e+000 1.000000e+000
      vertex 1.000000e+000 1.000000e+000 1.000000e+000
      vertex 1.000000e+000 1.000000e+000 0.000000e+000


  facet normal 0.000000e+000 0.000000e+000 -1.000000e+000
    outer loop
      vertex 0.000000e+000 0.000000e+000 0.000000e+000
      vertex 0.000000e+000 1.000000e+000 0.000000e+000
      vertex 1.000000e+000 1.000000e+000 0.000000e+000

In the future the STL file format is likely to be around for some years to come but in time it is likely that the format will be replaced by something like the AMF (Additive Manufacturing Format). Intitially known as STL 2, AMF is being designed on the XML (Extensible Markup Language) platform which means that it is flexible and can contain both geometry and additional information such as multiple materials and colours etc.

Since writing this in August 2013 a consortium of industry leaders has been formed to develop a new format known as 3MF. AMF has been pretty much dropped even though it became a viable format. As of March 2016 we have still not received an AMF file or had any enquiry about this format. 

These new formats are attempting to address the needs of 3D printing, additive manufacturing, copyright issues and other rights to reproduce. It is going to be complex and less accessible - I for one appreciate the simplicity of the STL file. "Simple is efficient" as my engineering drawing teacher used to say.

*In fact binary STL can support colour, if we save an STL from Magics we can open it again in Magics preserving the colour information. However the important point is that all of the STL file exporters written for 3D modelling software like Rhino, Revit, MicroStation, SketchUp etc do not export colour.

For further information about Lee 3D visit

Thursday, 1 August 2013

The Magic Of Magics RP

At the heart of Lee 3D is a piece of software called Magics.  This software is used around the world by leading RP and 3D Print bureaus to perform a number of critical functions that enable 3D parts to be fixed, optimised and built in most of the 3D printing machines available today.

Fixing and Optimising

Dealing as we do primarily with AEC data we use Magics for fixing and optimisation of files.  Fixing makes a file printable and includes simple tasks like filling holes, giving thickness to surfaces, stitching surfaces together and getting all of the faces (normals) in the file to face the right way.  Optimising makes a model look great and often reduces costs and includes thickening details, adding colour and textures, cutting up large models and hollowing. 

The real power of Magics is in it's optimisation tools.  These are tools that perform tasks that most CAD, BIM and other modelling applications are simply not built to do.  The  reason for this is that Magics has tools designed for certain functions but also because a meshed 3D print file is a much simpler dataset than a vector based CAD or a database driven BIM dataset. 

Key tools contained in Magics that vector based modelling applications either cannot do or struggle to do effectively are the cut, unify, hollow and the shrinkwrap tools. The shrinkwrap tool is an especially powerful tool but need careful use to ensure quality of output is maintained. It also can make use of a very powerful computer to fully exploit its strength.

A worked example - 1:50 figure
Staged file fix and optimisation of 3D print file

  1. Textured SketchUp File opened in Magics and scaled - the little guy will be 36mm tall when printed (He came from Trimble 3D Warehouse and was modeled by Max Grueter)
  2. Viewing of textures switched off to enable the errors to be clearly seen. Holes and bad edges are shown as yellow lines and inverted normals as red.
  3. The errors are fixed leaving some of the parts too thin to print at 1:50. 
  4. The file is optimised using the Shrinkwrap tool, adding 0.15mm all over and neatly retaining the image map on the new shell. The model is now robust and ready for 3D printing.

The viewing tools in Magics are a joy to work with. Instantaneous section viewing, the ability to change rendering and logical colour, toggle visibility and mouse driven navigation all help to work with complex files with ease. 

The texturing tool allows aerial photographs etc to be draped onto the geometry and maneuvered to line the two up accurately. Textured data can be cut up and chopped about with no sign or marking in the 3D printed model.

For Architecture
The ability to open SketchUp and Rhino files natively, side steps many annoying export issues from these applications and greatly speeds up the process. In addition Magics opens a large number of files including STL, OBJ, VRML, PLY and 3DS.

It used to be that only bureaus and businesses with in-house machines used Magics but increasingly design offices that outsource 3D prints to a variety of suppliers, providing different technologies, are starting to bring Magics in-house.  It makes good business sense to have Magics in-house, if files can be checked before they go out you no longer have to rely on someone else to make decisions about the data when they are fixing it.  Once you have a printable file it speeds up getting quotes and in theory it allows you to get the job done at the best price.  Though of course there is a lot to be said for sticking with one same supplier (Lee 3D) who can provide uniformity of service.

And last but not least a Magics file has excellent compression algorithms which make much smaller files for sending and consequently saving time in the process.


Lee 3D offers the following services in addition to 3D print bureau services:

File preparation services

File fixing and optimisation of files for 3D printing specialising in architectural, engineering and construction.  This service is offered globally.

Magics Training

Magics training is offered on-site or by Webex. Half day courses are available for beginners and advanced users who wish to use Magics for preparing architectural data for 3D Printing.
Magics Sales
The decision to buy Magics needs to be taken with the knowledge that you will get the right support.  Lee 3D offer user support for using the software in the AEC sector and in addition to this you also have access to support direct from Materialise. 

To find out more about Lee 3D visit