In the previous modules, we have covered each element necessary for a clear understanding of desktop 3D printing hardware. Now it's time for a very different type of anatomy lesson. Over the course of the next few lectures, we're going to take a closer look at the component parts of digital design files for 3D printing, including the software and processes that produce them. There might not be a physical organism for us to dissect here and as a result, no organs, tissues or skillful systems to set out onto the lab table. But it is essential that we take the time to work our way through the sequence of files and translations that take us all the way from a design in progress to the finished job file ready to be processed by printer. You'll get to see how these files are constructed, translated and adjusted to produce the final instructions. But first, to set the stage for these virtual anatomy lessons, to lay the mesh files out across the table, let's take a step back and ask an important question. What is unique about the process of creating projects for this technology? To make it nice, you have to make it thrice. Now this is the 3D printing, often ask me how do you put the design into the machine to get the printed object? Their top guess, you give the machine a picture or your drawing that then analyzes, understands and uses to create a 3D object, were that it were true. You might find that a photograph or a simple 2D drawing is helpful when creating a three dimensional object. But you will need more information for your final design. Consider for a moment all the important information about 3D object that is not captured in a simple snapshot or a concept sketch. How big is it? What's on the other side of the object that isn't visible in the photo? How does various parts and features connect to each other? Are the transitions gradual or start? What will the surface of the object be like? What are the mechanically significant elements of the part? Which elements are low barring and which are cosmetic? It would be easy to expect your computer or 3D printer to take a lost idea a hunch and dream up a solution for you. This is a prospect that's clearly on the horizon. Thanks to tools like Autodesk Generative Design and Topology, etc. But for now, the act of modeling is the task of working with software to resolve the ambiguities and opportunities of your first concept, your hunch. Your aim is to produce a digital object, a virtual template for the physical object that you want to produce with the printer. Someday, dozens of years from now, this stage might get easier. Fabricator and design development software might be able to make a thing with far less prompting than is needed these days. But for now, desktop 3D printers need more than a simple description of what is wanted and intended. 3D printers are just not nearly this clever yet. They need clear and precise instructions completely unambiguous step by step tasks they can execute. As a result, you have to build the object itself in software completely before you're ready for the printing stage. And in order to produce the right digital object, you need at least a basic plan for both the software process, and the printing hardware technology to target. And as a result, instead of a single step, the process you go through for 3D printing involves three steps. Let's take a look at these three steps in greater detail as a scaffold to help us better understand what is required. You may have heard the popular notion that the sculptor creates the statue first in her imagination and then in the physical world. And that architects build the building three times. First, they shape the idea of the form, second they resolve the fine design details and make it real, make it useful and deliver that as a blueprint. And third, those plans are taken by contractors who will construct the final form and details with real world tools, materials and products. With 3D printing, the three times rule is hardwired into the process. Concept, you've gotta have a plan, son. First, there's the planning stage. This is where you conceive of what you are looking to achieve. And when you select the hardware, software, materials, post processing strategies and more, it will guide your route to achieving it. While there are maybe dozens of files and sketches and photos and prototypes represented by this process, what you use is designers choice, largely up to you and what is helpful for you and your teams. The goal is to leave this stage with the basic project parameters that will inform the rest of what you do, identify when your project is done, and ultimately, show how well your plan worked. If you're creating the design on your own, you might never write this process down. If you're collaborating as a team or need to convince other stakeholders that you're heading in the right direction, you might put time and energy into producing tangible concept deliverables, in order to validate the plan before proceeding. Think of the many stages of exploration, concept, and modeling, over the lifetime of an architecture project. Modeling, use digital design tools to produce a virtual object. Next, with some sort of plan well in hand, even if it's just a hunch, you create the digital object itself. With some digital fabrication methods, where a lot of the critical effort takes place after the computer guided operation such as CNC routing, or turning, or laser cutting, or fabric cutting tables where the aim is primarily to put the scissors in the hands of the machine. The digital object you produce might not look like much. A single clever sweep across the monitor that looks almost effortlessly simple after all the measuring and planning is complete. Might be the seed shape at the heart of a complex, multi storey interactive installation, or card stock armature to reinforce a leather accessory. Here's for 3D printing stands out from its computer aided manufacturing peers. In many cases, the virtual object designed for 3D printing project can take on a life of its own. Think of the many online repositories for 3D parts and the creations that have received news attention and attracted fans and foes. All before anyone involved has even seen evidence of the physical object itself, the physical target that the design is a means of producing. Thanks to the tremendous range of tools for rendering and manipulating 3D digital objects. The creative process tends to reward the designer who creates a complete object with as much of the structural form material and arrangement of elements already in place. A complete design in a virtual domain will lead to a more fully realized physical object. The digital design is the most important part. Each 3D print itself can be seen as merely one in a series of objects that could potentially be produced from its digital file. Rather than a final version that eclipses the original visual design itself. The latter has traditionally been the case with prototypes on their way to becoming manufactured goods. But many designed and engineered products are headed in another direction. Objects possessing dual citizenship, able to pass fluidly between the physical world and the virtual ecosystem. Which has, of course, become a larger part of the contemporary world, influencing our jobs, lifestyles and marketplaces. So think of the virtual object as more than just the templates. They can be tools themselves, to submit to analysis or to share seamlessly with collaborators all around the world. They can capture a lot more information about what you intend to represent in the final printed object than what is depicted. In actually producing the object. This new way of thinking is closely linked to low cost materials and professional grade output. Even with fast processes like SLS and Binder Jetting, which are perfectly inexpensive, relative to previous available technology. The pieces were too fragile and too costly to be quite as disposable. Job prep, use 3D printer control software to produce printer instructions. One more stage, you aren't done yet. You have to make the object one more time. The most important stage, you need to translate your digital object into a conceptual template, representing what you want into a set of clear instructions for the machine and materials at your disposal and set the desktop factory to work. There are many ways to fabricate that digital model and you need to select the exact ones. Remember that the 3D printer hardware is eager to be helpful, but needs very clear instructions what to do. Fortunately, you can lean on materials and printing profiles to get you most of the way there. The final deliverable for this stage is a job file, typically a g-code file. We will be exploring this in greater detail in this module. Bring your design to plastic life. We are going to zip our way through the process of bringing a model to plastic life. We're going to take the ultimate your robot mascot again. Let's move from the concept sources through to the printed model, paying careful attention to the form that each stage takes and the process of translating from one design stage the next. From a 2D illustration to a 3D model. Imagine what 3D form suits the design. Starting with a sense of how the viewer will engage with the final physical robot. The goal, to offer an experience that matches what you feel when you see the striking 2D robot sticker. The model designer created the 3D form using SOLIDWORKS. Building up each element in relation to other elements to produce a parametric model. Because the 3D model is very different than even a 2D model that suggest three dimensions, the designer took liberties with elements to show how to define the volumes in three dimensions and how each piece intersects. As a comparison to help you consider the challenges moving from 2D illustration to 3D volumetric modeling. Take a look at resources online showing the process of attempting to produce 3D game character models from the 2D Simpsons character illustrations. Characters that are almost always present in profile only, despite thousands and thousands of representations of partial profiles from multiple angles. Simply meshing together those views produces horrifying results that do not suggest the original characters to viewers. Likewise, elements that make the Altibot mascot a great illustration do not directly translate into an appealing 3D sculptural form. Let's take a look at the digital design file. I didn't create this design, but the designer shared the original design files so we can take a look inside and see what it looks like in there and make a change if it's possible. The way that the geometry is both expressed and controlled has been selected by the design software developers in ways that are focused on the ability to efficiently produce and alter the features there. As it happens with most professional CAD software, until the design is baked into triangles, there are many aspects of the design that can only be expressed abstractly. Exact placements and points are not determined. The design software version of a digital design is recorded in such a way that is focused on the designer's ability to create and modify the design. These virtual imprecisions are not only handy for focusing on the design decisions, they are also typically a lighter load computationally for the computer that hosts the software. The designer's task at the end of the digital design process was to produce a mesh model, an SDL, that could be exported from SOLIDWORKS and would be suitable for import into the 3D control software. In this case, Ultimaker Cura. 3D printer software doesn't natively speak SOLIDWORKS, Rhino, or Fusion 360, etc. So the last step of using this sort of design file is to select the geometry you'd like to fabricate and export it. But luckily for 3D printer operators just about every 3D design package can export a decent mesh file. In order to produce a good mesh output, a few conditions must be achieved in the design software. The geometry must be solid and watertight. This means that if you have a complex surface for example, it has no thickness, you need to extruded so that the mesh export operation can put front back and all the sides onto that surface. You also need to be mindful of overhanging parts. If there is no material in the design to support a feature higher up, you will need to use one of the support strategies to preserve this feature. Otherwise, the printer will do its best to deposit material where you want it and the material will sink until there's something to support it. And finally, the features that you want to be expressed in the printed model need to be big enough and thick enough that the printer can produce them by squishing out a beta filament. The model was published on the YouMagine digital model repository along with a number of other resources including step files and SOLIDWORKS files that permit other designers and engineers to import this model back into a professional parametric CAD program like Rhino, or Inventor, or Fusion 360. Also note the details for the license selected by the designer. From digital design to virtual part template. I didn't design the robot, I grabbed it from YouMagine and the first stage was simply to download a copy of the mesh SDL file that defines it. Opening it in the Ultimaker Cura software. I can see what it looks like at the one to one scale defined in the design file I collected. What files do I used to bring the design into Ultimaker Cura and start the process of preparing the job? This STL mesh file here. This mesh is an export file created by outputting the object from the original design software used to create it using a format that is easiest for 3D printer control software to work with. A mesh file like this one is made up of a long stream of code that describes the points and orientation of the thousands or even millions of tiny triangles that together represent the outside surface of the digital object of print. This file is used downstream of the design software itself, because this way to represent the surface is much more difficult to modify than how the design file stores information about the model. So why use this mesh format at all? The reason has to do with how the geometry information will be processed in the 3D printer control software. 3D printer control software needs to use this simplified triangle description of the surface in order to translate the design into the instructions for fabricating the object, starting with the ability to slice the entire object into a series of horizontal slices. The hundreds of scripts that make up a slicer dependent processing the right kind of data, so the machine instructions can be easily produced. By convention, the STL mesh format is the most common, but there are a few other related mesh formats that can be used as well, OBJ, 3MF and ANF. Note that as Ultimaker Cura as a number of interoperability plugins for professional CAD packages. It is easier and easier to quickly produce a printing software ready mesh from the submitted design files. What we're saying to remember about HTML meshes? The units are not strictly defined. And I don't need to honor those units in any case. I want to make a big printed robot, so I'm going to scale this model up 500%. Using the transformation and translation tools within Cura, I commit the design to a specific physical scale and position. Now, I have it within the virtual build envelope of the 3D control software the way I want it. But I'm not done yet. I need to make any necessary adjustments to the path planning tool, the 3D slicer, that will reinterpret the mesh of the design according to the parameters I feed to it from virtual part template to G-Code job file. Moving across the top bar of Ultimaker Cura in the prepare mode, I make sure I've selected the correct machine, and Ultimaker 3 in this case. I selected an AA 0.8 millimeter core and Ultimalker silver metallic PLA for tool head one. I selected a BB 0.8 millimeter core and PVA natural for tool head two for the support material. I selected the available fast quick print profile in Ultimaker Cura knowing that I can configure my own sizing profile from scratch should I need to. In the case a small, I'm happy to use the quick print profile and make only a few adjustments. I leave the setting for 20% infill and toggle the checkbox for support, and select extruder two under the selected tool head option so that PVA will provide the support I need. I also make sure that the checkbox for adhesion remains on, which will default to a brim. And I check in custom that the brim setting will be accomplished with the second extruded. But otherwise, I'm totally fine with a defaults in this case. I hit this Slice button on the bottom of the screen and the model is quickly sliced for me. I now have the specific set of instructions that my chosen machine will use to produce the object that I want. I can take a glance at the paths that have been chosen in the preview view, adjusting the layer slider on the right to see how various layers have been designed throughout. Then, I head back to the prepare mode and export my files for printing. My habit, one I encourage you all to follow, is to add date and time information to the front of your G-code every time you print. While that adds characters that can be annoying for other older model printers to show on the interface, it does mean that you can always locate this file on your laptop and know when you created it. A much better way to recall your decision making than writing final version, revision two, urgent deadline version with that change etc., into your file name as tends to happen. I also save a copy of the project itself. This preserves an easy to review set of all sizing details. Looking at this in association with the G-code file that has those decisions baked into it, makes it trivial to determine precisely what setting to use at that time, allowing you to use the project as a template file in the future if you want to start from the point of those same decisions. So now, I put this file on a USB thumb drive and cross in the physical world over to my machine. Time to calibrate and configure my machine. Insert the right material and core nozzle size and deliver that G-code job file to my printer for fabrication. Sometimes following the instructions is not enough. Just because I have what I believe is the right file on the right machine with the right materials, I'm not guaranteed success. When I mentioned the concept of a 3D print being experienced as an element of a set of potential objects produced by the digital design, I didn't just mean this in terms of using digital designs that change. If you run the same code many, many times, you may be able to determine slight differences in each of the models. It is a key goal for all desktop 3D printer vendors to do what is possible to ensure that each print is as close to identical as possible, regardless of when and why you printed it. But you are designing for a process, not designing for a perfect instantaneous fabrication method. The key elements are temperature and humidity factors, age of filament, and condition if your build plate. But generally, because I planned well and picked the right equipment, I get pretty much what I want. Didn't print perfectly? I just tweak the printer and run it again, something I have to do far fewer times each and every year this field continues. Let's explore this in reverse. Zapping your model into digital triangles. Now, let's quickly review this three-fold design process for creating a specific printed object by working in reverse, back from the physical printed object. This is an opportunity to inspect what is critical about each stage that helps you make decisions in the other stages. Printed part, Ultimaker 3D printed robot. Ideally, you don't look at the final piece and only see the means by which it was created. But if you do look closely at any untreated, unscented desktop 3D printed part, you can divine certain details indicating how it was created. Specifically, printing orientation, layer height, thread width, shells, and infill. Each of these decisions leads to a physical effect on the final fabricated object. Let's take a look at the ulti-bot robot mascot we printed before. Flipping it over, we see evidence of the printing orientation and the basics of the fabrication instructions followed to produce the object. The bottom layer is glossy because it was in constant contact with the glass of the heated bed. The heat plus the smoothness of the glass plate leaves a surface that is more uniform and reflective than if a coarser tape or substance was used. You can also see multiple outlines that trace around the outer contours of the single XY layer slice and the pattern of infill filling in the rest of the space. Because the top and bottom layers tend to be solid infill layers rather than partial infill sparse layers, we don't know that much definitively about the percent of plastic infill on other layers in the part. But through heft and squeezing the part, we can get a pretty good idea that it isn't 100% infill. Looking at the paths of the material, we can get a sense of the line width. How thick were the beads being treated by the nozzle? The bottom level with the constant heat tends to spread wider than the other layers, so we can't tell precisely. But we can guess whether the nozzle was 0.4 millimeter, the standard nozzle size, versus 0.8 millimeter, a much larger nozzle size, as we used here. We can also see that the pattern of the infill used for the bottom layer, line versus concentric, for example. If we had inspected the entire build plate instead of removing the part, we would have seen other elements as well. Purge material at the start of the print, the adhesion strategy, in this case, brim, which traces a little offset line around the basic part and extends it out. A great way to determine from the first layer how accurately the platform calibration has been across the plate. And whether an adhesion strategy such as glue or sheets is functioning well. And there is more evidence in the job files that produced the object. The act of leveling and homing actions at the start of the print, and the stages after the print is complete to reposition the print head and platform. Virtual part, Ultimaker 3D printed robot in Cura. So after looking at the printed part, let's take another step backwards and take a look at the Cura 3D printer control software for the job preparation stage where the decisions about how to fabricate the object are selected. Here we are in Cura, and you can see the part that we printed already in place on the build platform at a one-to-one scale that was used when it was printed. And while placing, scaling, and orienting the object is already much of what we need to do to define the job, the real work happens under the hood with the slicer configuration elements on this side here. If we go back to the preview view within Ultimaker Cura and study more closely how the outer shells and infill are executed on each layer, we'll recognize how these path choices at the software level are then represented in the final form. In fact, it is very handy to review these decisions. At the path level connected with an imperfection that catches your eye on the final print. Was the error created by the machine performance, decisions at the slicer level? Or can you trace the issues back further, all the way to a problem with topology or in the design file itself? The Preview tool is your greatest ally to solve those kind of mysteries. We can see in the original project how the original digital design model was imported. What transformations and translations were performed, scale, rotation, position, as well as all the operator-selected slicing decisions. For the most part, the decisions I used were based on the fast-print profile. Let's take a look at a few of the details that this includes. Now, let's take a look at the G-Code file that results. Going back one step further, we can open the original SolidWorks part file in SolidWorks. And determine if the process of reducing a mesh and exporting it was sufficient to our needs. Did we execute a mesh that had too many or too few triangles? Are there small details we'd like to push in or pull out slightly to better suit the final sculptural form we are producing? Conceptual part, Ultimaker mascot design and sketch. So now, returning full circle to our conceptual plans, the 2D design file and the conceptual plans for how to use the digital design to produce a 3D model of it. And how to use Ultimaker 3 and Ultimaker silver metallic PLA to produce it and PVA natural to support it. Because we don't have the designer here to tell the conceptual part. For the conceptual stage we'll just have to judge based on the 2D concepts that the designer worked with when creating. So how did we do? Did we succeed in the goals we set out for ourselves with this design project to represent that dramatic 2D illustration that suggests three-dimensionality as a true volumetric 3D model? What do you think? Think there are features and elements you'd try a different way? Download the original source files from 2D reference through the SolidWorks part and mesh files, and produce your own version. Many have done so, including many who take that original robot model and put it to other uses. Everything from producing jewelry and cufflinks to making Halloween costumes and Christmas ornaments. Have fun moving through the three-stage process on your way to producing a model of a robot of your very own. In the next several lectures, we will explore the files and formats of each of these multiple design stages in greater detail. And the next time you design a project for digital fabrication, pause to consider these three versions of your project that you create. This can help you better identify when in your process to commit to the materials and processes that you will need to achieve a specific result.
