Teach to use CAD or through using CAD: An interview study with technology teachers

When designing, technological problems are solved and products, artefacts or systems with a specific design are developed and documented through for instance a model. In that sense, design has similarities to problem solving and product development (Buckley et al., 2020). The two concepts, design and problem solving are often used in a similar manner and interchangeably in technology education settings (Gibson, 2008). Design processes are described differently based on various perspectives of different authors. For instance, Middleton (2005) describes the design process used in design and technology programmes in schools as follows: identifying a problem, undertaking research, developing solutions, producing solutions and evaluating solutions. Further, De Vries (2016) writes that design processes can be divided into three main parts: analysis, synthesis and evaluation. In the analysis phase, the problem is analyzed, in the synthesis phase, solutions for the problem are proposed and in the evaluation phase, the solution is assessed against objectives and criteria stated. Williams (2000) describes technology processes (like designing) comprising several activities like evaluation, communication, modelling, generating ideas, research, producing and documenting. The activities, parts or phases in design processes are iterative and repeating (Williams et al., 2012). Not all of these activities are used in every process, however (Williams, 2000).

In the design process, when pupils are in the phase of developing solutions, models and sketches can be used (Williams et al., 2012). Models can be designed digitally in a CAD program for physical and/or functional properties, or for intrinsic and/or intentional properties (de Vries, 2016; Nia & de Vries, 2017). The physical or intrinsic properties when designing refer to for instance size and form of the model, and the functional or intentional properties besides the function of the model also ethical and aesthetic aspects and ways of communication (de Vries, 2016; Nia & de Vries, 2017). There are several types of CAD software suitable for technology education in lower secondary school, for example TinkerCAD (www.​tinkercad.​com) and SketchUp (www.​sketchup.​com). In addition to the usefulness of modelling in terms of learning, the models created by the pupils also allow teachers to grasp pupils’ technological knowledge (Elmer & Davies, 2000; Welch, 1998), a knowledge not easily expressed verbally (de Vries, 2016). In that way, the created models can be understood as a form of documentation and communication.

Ginestié (2018) describes two different types of teaching related to design processes; one closed type of teaching where the teacher guides the pupils through the problem, and one open type of teaching where the problem is presented to the pupils but no solutions are given. When teaching is open, pupils are encouraged to learn by discovery, and the exploration stage is important. While exploring, sketches are effective and important to find different solutions to the problem (Ginestié, 2018; Lane, 2018). A sketch can be a few lines on a paper or it can be a more developed drawing of something. Sketches are primarily used as support and a tool for the design process (Delahunty et al., 2020). In engineering graphics courses, teaching sketches is suggested to start the course, to improve the students’ ability of visualization (Jerz, 2002). However, research shows that when pupils are presented with a technological problem, they often start constructing a solution directly, and few pupils start sketching (Welch, 1998). This approach results in serial solutions. If one idea is dismissed, pupils often start from the beginning with a new model without sketching. Similar findings are presented by Christensen et al. (2019) who state that novice designers in a middle school setting often start from their first idea, and design just one solution to a problem. The teaching is important for pupils’ learning whether open or closed, and Elmer and Davies (2000) write that teachers to stimulate the learning process when pupils are designing and working with design processes, should be observing, initiating, participating, encouraging, maintaining and extending in their teaching approach. However, research indicate that teachers in middle school settings lack knowledge of design processes and therefor have difficulties teaching design processes (Christensen et al., 2019). So how teachers choose content, design lessons and act when teaching CAD can be a decisive factor for pupils’ learning. This leads to the section Teaching CAD where findings from research from upper secondary and university levels are presented.

A CAD course can be organized in many different ways (Gelmez & Arkan, 2021; Gül, 2015). Traditionally, CAD pedagogies starts with teaching commands for pupils to be able to solve specific tasks (McGarr & Seery, 2011). This tradition is also used in post-primary schools, targeting on teaching how to use the software (McGarr & Seery, 2011). However, today, core contents of technology education are based on creativity and design and perhaps other methods for teaching CAD are better suited than a traditional pedagogy (Delahunty et al., 2020). Alternative CAD pedagogies are teaching how a CAD system works instead of teaching CAD through a specific task (Menary & Robinson, 2011). Chester (2007) argues that teaching to design in CAD requires several types of teaching; teaching that aims for declarative/procedural command knowledge and teaching that aims for strategic knowledge. Declarative knowledge is the general knowledge about the commands and algorithms within the software, as well as about understanding the commands and knowing what commands are available. Procedural knowledge concerns handling and executing the commands in the software and knowing when and how to use different commands. Strategic knowledge concerns how to create a design and how to make modifications, how to construct solids and surfaces, and how to easily change and choose between different modelling strategies. A pupil designing in CAD needs all types of knowledge described above. If one type of knowledge is underdeveloped, it will affect the pupil’s ability to solve the task (Buckley et al., 2018). A recent study states that a CAD pedagogy containing telling-to-peers or writing-to-peers communication, enhance pupils’ strategic knowledge and use of the software (Gelmez & Arkan, 2021). Further, Chester (2008) states that pupils will be better prepared for new CAD programs and updates in the software if the teaching focuses on strategic knowledge and allows pupils to acquire declarative/procedural knowledge meantime. Other research also questions whether traditional teaching (starting with declarative/procedural knowledge) is the most appropriate way to promote learning (Bhavnani et al., 2001; Garikano et al., 2019). Pupils need to acquire knowledge of how to create a model, but they should also be able to motivate the choices made in the creation of the design (Menary & Robinson, 2011). Moreover, introducing a new technology to a practice can entail challenges (Delahunty et al., 2020). Teachers need more than just declarative/procedural knowledge to be able to help pupils with their problems (McGarr & Seery, 2011). They also need to transfer procedural knowledge to other CAD software (Bhavnani et al., 2001). This is in line with other challenges with teaching CAD, for instance that CAD software are continuously changing (Gelmez & Arkan, 2021).

Further, research shows that many pupils get stuck learning the commands of the software instead of trying to find different solutions to the specific problem presented to them in a task (Chester, 2007; Leisney & Brandt-Pomares, 2015). This is problematic, since pupils may not develop adequate problem solving skills. Leisney and Brandt-Pomares (2015) also discuss how an early introduction of digital design tools can negatively affect the number of possible solutions to the task. A digital tool as CAD can enhance pupils’ visualization and communication skills, but on the contrary, an early fixation in the design can limit other the possible solutions (Robertson & Radcliff, 2009). So, a result of letting pupils start designing digitally, is often a shallow form of learning due to the fact that they are dealing with double challenges, complex software and solving design problems (Chatoney & Laisney, 2019). Pupils who would like to explore different solutions to a problem must therefore quickly learn to operate the software (Charlesworth, 2007). A lack of software knowledge, or declarative/procedural knowledge (Chester, 2007), may otherwise lead to a great deal of time spent on presenting an idea instead of developing ideas.

Charlesworth (2007) adds that pupils working with digital design processes tend to work linearly, with fewer alternative solutions. However, when designing in CAD, more solutions to a problem can be developed if a pupil first begins to make sketches for the design (Delahunty et al., 2020). This is a result that Ginestié (2018) and Lane (2018) also found when pupils were solving problems, even though Ginestié (2018) and Lane’s (2018) study concerned designing without a digital tool such as CAD.

With this background about teaching design and design processes and teaching CAD at other educational levels as a point of departure, it thus appears important to investigate how teaching concerning CAD is planned in relation to what the teachers intend the pupils to learn, in lower secondary technology education. There is a need for communicating what the pupils should learn when teaching CAD, before educating pupils and developing pedagogies for teaching CAD (Menary & Robinson, 2011).

During October 2018 and September 2019, the first author collected data for this study in Swedish compulsory school. Compulsory school in Sweden stretches from grade one to nine, and has mandatory technology education for every pupil in all grades. Lower secondary school is education from year 7 to 9, and pupils are aged 13 to 15 years. The subject teachers transform the national curricula core content into more specific intentional learning outcomes.

Twelve lower secondary teachers participated in the study and were chosen strategically to get a broad variation of experiences, rather than to compare groups of teachers (Alexandersson, 1994; Kvale & Brinkmann, 2014). Participants with different backgrounds, gender, teaching experiences and education were contacted. Contacts were established from three different networks; A medium-sized university, Swedish national center of technology education and from local teacher networks. However, it was important that the interviewees and the first author had not previously worked together to avoid implicit understandings, which may affect the results of the study (Kvale & Brinkmann, 2014). It was also important that the participating teachers teach CAD, or that they have previously taught CAD, to ensure that they have experiences to describe. The interviewed teachers, seven females and five males, have been teaching the technology subject for between 1 and 19 years. Some of the interviewed teachers work in a small school without colleagues in the same subject, and some of them work in larger schools with more technology teachers in service. All teachers have formal teacher education, but three of them lack diplomas of certification for teaching the technology subject. This is an expected division, since only about half of the in-service teachers teaching technology in lower secondary school have formal education for teaching the subject (Skolverket, 2019). Se Table 1 for further details.

Twelve semi-structured individual interviews were conducted with the twelve teachers. The interviews were held at the participating teacher’s school and lasted for 35 to 60 min. During the interviews, the researcher asked open questions within this specific area of technology education to help frame the phenomenon of teaching CAD, and to make sure that different perspectives on the phenomenon were fully covered (Alexandersson, 1994; Kvale & Brinkmann, 2014). The questions were centered around digital modelling and what the teachers describe that they are teaching, see Table 2. However, the open questions also concerned how the teachers are teaching, with the aim to help the participants broaden and deepen their descriptions. The participants described their teaching in their own words and in ways they found necessary in order to explain it. However, complementary questions (see Table 2) were frequently asked, to elucidate the teachers’ descriptions.

The interviews were recorded digitally and transcribed by the same researcher who conducted the interviews. The positionality of the interviewing researcher was to, in every step of the study, holding own experiences aside, not to bias the participants although there are interactions between the parties (Bengtsson, 2013).

The analysis process started with listening to the recorded audio files and reading the transcriptions. This listening and reading were iterative and in parallel with the interviews to establish a holistic view of the data material. At the same time, the search for extracts pertinent to the phenomenon started. Usually, tentative categories can be established early during the data collection (Marton & Booth, 1997), as in this study. The first tentative categories were formed around teaching commands in the software and the use of 3D printers to make physical objects.

The analysis process continued with extracting units of description from the transcripts, as significant words or expressions used by the teachers showing the same thing or concerning the same content. Similar words or sentences were coded. These units of descriptions were grouped in different constellations to find similarities and differences between them. One example of correlation is when two different teachers describe how they explain to pupils that models designed in CAD need to be attached to each other for the 3D printers to be able to print the model correctly. The two teachers describe this differently but the interpretive meanings are similar, and the units are therefore grouped together. The extraction of units of descriptions was ongoing during the interviews and more units of description were found and grouped continuously. After nine interviews the groups were stable and the units of descriptions were categorized. Three more interviews were conducted to found out if the data material had reached saturation, but they gave no further information, and no new units of descriptions or categories were identified. The differences between the units of description constitute the demarcations between the categories. The first author grouped the units into categories but all three authors discussed and modified the categories together during the analysis process before the resulting categories were final.

The experiences of teaching CAD in this category relate to handling the software. The ILO when teaching CAD described in this category holds just a few variations; to introduce the software to the pupils and to teach the pupils basic commands, functions and symbols. The teachers describe that they want the pupils to be acquainted with the software and that they can try it out.

Oh, the seventh graders are doing key chains. The task is actually to be acquainted with design tools. (Teacher 8)

The interviewed teachers give examples of experiences explaining that they introduce CAD at a very basic level. The teachers show pupils simple commands, symbols and functions of the software in question. The teachers explain that the digital models that pupils create using CAD are simple and have distinct geometric shapes. Teacher 2 puts it as follows:

And that you kind of understand things about shapes and how you can rotate them. […] They get to try to just simply make a cone, make a box. They can pull it out, expand it and trim it. […] And much is about handling the software. That you understand how to use short commands. […] And in TinkerCAD [digital design tool], how you turn different objects around, so you get, this is a cone, but now it is turned upside down. It is still a cone. Same thing but upside down. (Teacher 2)

Jewelry or name tags are common objects for beginning to learn CAD. What is designed is not important in this category, according to the interviewed teachers, since the ILO is to learn to handle the software. When pupils create these objects, they use basic geometries from the software toolbar and combine them into their own objects. One teacher describes teaching as based on the idea that the pupils have to be allowed to play around in the digital design tool.

So they should be able to klick and play, you can call it that, and learn the program. (Teacher 7)

In this category, teachers sometimes show what they are doing by connecting a projector to their own computer in the classroom, and the pupils follow the instructions and copy what the teacher is doing. An alternative is to use YouTube tutorials, and let the pupils copy and emulate what the YouTube clip shows.

In this category, the experiences of teaching CAD relate not only to handling the software, but also to using ready-made models (in the software). The ILOs in this second category is based on the ILO from the first category and more variations are added. One added ILO is part of the design process, developing solutions (Middleton, 2005). Pupils can understand how models are created and the interviewed teachers express that pupils discover the difficulties involved in making advanced models on their own. However, the teachers describe that they want to show the pupils the possibilities of CAD and that most models in fact are based on basic geometrical forms. The second added ILO is that digital objects and models can be a sort of documentation, a modern blueprint.

In this category, pupils are allowed to freely explore the software. Pupils are encouraged to search for models made by others for inspiration. The interviewed teachers say that pupils can use ready-made models collected from databases, galleries and libraries connected to the software. By fetching ready-made models, pupils get opportunities to see what is possible to create and design digitally. Teacher 1 describes how pupils use these galleries.

TinkerCAD has a very good gallery, where you can enter and look around. […] They [the pupils] like to go in there and look. They often take things from there. (Teacher 1)

Teacher 2 talks about these galleries in a similar manner.

Yes, you can search and find. It is like an open community. There you can see someone who have built a robot with ninja swords and you think this is awesome, I would also want to do that. Then you discover that it is about basic forms. You work with cubes and diamonds, and things. Someone has put those forms together to a robot. (Teacher 2)

According to the teachers, neither tutorials nor YouTube clips are used so much in this teaching since pupils already know some beginner commands in the software. Pupils explore the galleries on their own and design models according to their own ideas. What is designed is not important in this category, just like in the first category, according to the interviews.

The third category, manufacturing and creating printed models, is even more developed. It includes the first category, as well as parts of the second category, handling the software and documentation. The ILOs in this third category is to make the pupils understand a different part of the design process than in the second category; to manufacture and create printed models i.e. producing solutions according to Middleton (2005). In the interviews, the teachers point out that it is important that the pupils understand the principles of how a 3D printer works, that the printer fabricates objects one layer at a time and cannot start printing from surfaces that are not supported from below. The following excerpt shows how Teacher 3 explains the principles to the pupils and also that the printed model per se is not important.

But otherwise, the task is open. And you cannot print this thing because it [the printer] will be printing a little bit here and then move and print more there, then move again, and well, yes. I think they understand the principles. (Teacher 3)

In this third category, as in category 1 and 2, the task and what is designed are not decided beforehand by the teachers and pupils can choose what to model based on their own preferences.

So, the task hasn’t been more controlled than that. Now I should do something in TinkerCAD that can be printed. (Teacher 3)

In this category, interviewed teachers express that the 3D printer can be used as a modern manufacturing method, since 3D printing is a fast way to produce a physical model. The interviewed teachers want to expose the printed physical model as a means in the iterative design process and as a physical documentation. But the physical printed model can also be an end, a complete object ready to use. In those cases, it is not necessarily the pupils themselves who have designed the models. The pupils are allowed to fetch and print ready-made models from digital libraries and databases.

The pupils are not always given the opportunity to print their models, since the focus is on the 3D printing method itself. Teaching is about the manufacturing method. Printing models is time-consuming in a school context, and according to the interviewed teachers, problems tend to occur when pupils are allowed to use the printer by themselves, which is why this is not always allowed. Teacher 12 discusses this problem in the following excerpt.

But sometimes you have started something [a print], and they [the pupils] have come in groups and just looked at how it works. And then the printer has been printing when you are not present. (Teacher 12)

Teachers with experiences in this category explain 3D printing principles through telling the pupils about props and supports and showing them printed models which have not been supported so that the thermoplastics, the filaments, are suspended midair. Teacher 3 gives an example of a printed car that was not successfully designed for printing.

I have explained [to the pupils] that it [the 3D-printer] cannot start printing in the air. If so, the threads will be hanging. (Teacher 3)

This teacher told that this failed car is often shown in teaching situations to demonstrate to the pupils the principles of the 3D printer and what will happen if models are not correctly designed in the CAD software.

Experiences related to the fourth and most developed category concern designing. This category also includes experiences from the three previous categories. When teaching CAD according to experiences related to this category, ILOs are parts of the design process, to design strategically in CAD and to create surfaces and solids efficiently. ILOs from previous categories are included. To design strategically, the interviewed teachers with experiences referred to this category explain that pupils have to learn more advanced commands and functions in the software. They practice working with different planes and depths as well as various axes in a three-dimensional coordinate system.

The interviewed teachers describe experiences of teaching the pupils that all parts in a model, for instance the letters that make up the text of a key tab, have to be linked to constitute a unit. If the parts are not linked, a 3D-printer will not be able to print the object, even if it looks correct on the screen. In this category, the model to print is in focus, not the printer per se.

There are so many steps when you model an object. So, there cannot be a gap between the legs of the chair and the chair. Or the key tab, it happens often, the letters are wrong, they are not attached to the tab. (Teacher 8)

The interviewed teachers also give examples of experiences pointing out that they teach how to create models by removing surfaces and solids instead of building something. For instance, one teacher describes how pupils are given the task to design a house, and the teacher wants the pupils to start out from a cuboid and then cut out smaller cuboids to create rooms, windows, and doors.

… and they will design a house, it is a completely different way of thinking. In SketchUp [digital design tool] you drag in a box or a cuboid. And that box, well there you remove the kitchen. To make a kitchen, you need to take off something. (Teacher 8)

To experience teaching CAD as in this category Designing is a question of making a model in accordance with objective criteria and specifications, a best practice of modelling. Some examples mentioned during the interviews are if the model has the correct measurements (has the right scale been used?) and if the desired function is achieved (will the door in the room open the right way?). Moreover, problem solving is also mentioned during the interviews as finding different ways to handle the software to achieve a certain desired feature for the model. A solution to this problem is for instance when pupils find a YouTube clip that describes how to make the wanted feature. Pupils copy and emulate the instructions from the clip. Teacher 9 gives an example:

So they [the pupils] copy tutorials, watch, how did they do it. They have searched, they are aware of the problem and they have found a solution to the problem. (Teacher 9)

In this category of experiences, teaching is often adapted to each individual, and the teachers give examples showing that a great deal of the pupils’ work is done on their own terms. The pupils are allowed to explore the software independently, and freely select a model to be designed, as in the previous categories. The teachers taking part in the study experience that they teach strategies of digital design in CAD, how pupils can effectively create digital models that allow for adjustments and changes. Sometimes teachers allow the pupils to remodel fetched objects. They explain that just fetching an object (or model) is not so difficult and they want pupils to learn to use different commands in the software to be able to make changes and adjustments in the models.

Well, I say that you can take a ready-made object, if you change it, so it becomes your own. (Teacher 1)

The teaching, according to the interviewed teachers’ experiences, focuses on pupils doing and redoing, changing, adjusting, and trying out different alternatives and options. When results are not as expected, pupils are encouraged to find solutions on their own or together with peers. According to the interviewed teachers, pupils turn to each other when they need help with the CAD software. Sometimes, pupils can be assistant teachers.

The results show four different categories of experiences of teaching CAD. The categories are the result of the various ILOs. The variations of ILO are sometimes to be seen as a set of variation where different ILOs are co-existing and simultaneously understood by the teachers. One example is in category 2, when developing solutions using a CAD software constitutes documentation at the same time. The categories are hierarchically organized from a less complex category (1) with one ILO, to a more complex category (4) with more variations or sets of variations in the ILOs. A summary of the outcome space of teachers’ experiences of teaching CAD and the (sets of) variations of ILOs is presented in Table 3, where also examples of teaching content are shown.

The hierarchical structure of the categories can be further explained visually and is shown in Fig. 1. Category 1 is the middle circle in white, holding one variation. The ILO from the first category is included in category 2 (light gray). ILOs from category 2 are included in category 3 (middle gray), and so on. However, there is one exception. The ILO “developing solutions” from category 2 is not included in category 3, but is then again included in category 4 (dark gray). All the other ILOs are a part of the next category.