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In the previous post we saw the aspects about the use of curves in styling. Now we're going to see the last phases of styling: 3d modeling and clay modelling. Then we will see the digital phase. During these two next posts we will see the importance of CAD in automotive design, and some interesting differences.
2 - 3D CAR MODEllING
3d car modelling
Once we obtain the final sketches, we need to take them from the paper to the computer to submit the different proposals. For this stage, the vehicle criteria (dimensions, number of seats, etc.) will be fully defined. But the design team will continue to work to realize the idea and make aesthetic adjustments to the vehicle body. This step is of great importance in the final styling of the vehicle.
When we talk about 3d modelling, in this phase, we always talk about Surfacing or automotive surface modelling. This is part of computer-aided design (CAD), but to further differentiate it, it can be referred to as CAS (Computer Aided Styling).
We will see the different CAD program options available. It's important to know which CAD program to start learning with if we want to focus on this field, since it's different to design in 3D from an artistic point of view than from an engineering point of view. Once you know if you want an artistic or engineering approach, you don't have to worry too much about which CAD program to choose; because it's relatively easy to go from one Cad program to any other Cad program, saving some differences.
There're a lot of different programs to start with. We will try to summarize as best as possible. Now we will focus on CADs for the artistic phase, and in the next post we will do on CAD programs that are focused on the engineering phase.
CAD programs are used for all types of industries, but here we will focus on classifying programs for automotive design.
DIFFERENCE BETWEEN CAD SURFACE MODELLING AND CAD SOLID MODELING
Difference between Cad surface modelling and Cad solid modeling
Surface modeling: Elements are generated through NURBS surfaces with negligible thickness. They're worked as if they were ultra-thin sheets where the only concern of the designer is the exterior design, the volumes and the surfaces continuity. Aesthetics are prioritized over engineering. Despite this, it's important to have technical knowledge so that the exterior design is consistent in the later phases of design.
The advantage of this type of modeling is that it allows you to create much more complex surfaces than those created with solid modeling. Here you begin by modeling the car with lines, and through these, surfaces are generated that give shape to the vehicle.
Once the car is modeled, it's possible to close the surface sets to generate a solid, but this isn't their main function. Mass attributes can be added to these solids, but if further technical study is required, it would be better to choose solid modeling. So in summary: For the artistic way, programs based on surface modelling are more recommended, and programs based on solid modeling are more suitable for engineering.
Another advantage of this type of development is that the designer doesn't need to worry about technical solutions such as screws, wiring or welding. The intention of this design is to create the concept from an aesthetic point of view.
In the post-treatment of CAD designs, graphic design tools are used to improve the cat visualization, such as KeyShot for rendering, and Photoshop for image editing. In this type of work, the presentation of the vehicle prevails. Volumes, proportions and main lines of the vehicle must be easily appreciated.
Solid modeling: The starting point is a solid, and material is extracted or subtracted to form the element; which will be fully parameterized. Measurements tend to be much more exact and concrete than in surface modeling.
With this type of modeling it's possible to simulate the element from an engineering point of view; so aesthetics are on the second level. Instead, it presents a greater difficulty to model complex surfaces.
In the post-treatment, CAE (Computer Aided Engineering) tools are used to calculate and simulate the different components. Graphic design tools aren't relevant here.
Below we can see two images of Cad in the digital phase in the facilities of a large manufacturer. Aesthetics lose all importance. We can see the big difference that it makes to design a car from an artistic point of view, to do it from an engineering point of view. These Cads are Catia and NX.
We have to consider the following: The images above are common in an office with huge teams of engineers, one person isn't expected to design everything. In fact, unfortunately, in reality, a large part of these designs are based on document management and communication between teams to be sure before making any minor design changes. This is because thousands of units will be produced after designing a real car and hundreds of jobs will depend on it. In other words, the responsibility is overwhelming in this type of design.
There are programs and intermediate solutions that allow a single person, or a small team, to design their own car. In these cases, the elements are simplified, for example, for an engine, a solid block can be used that represents the space occupied by it.
Below we see a Reynard designed with SolidWorks, that design is considered complex to be designed by a single person.
We will see more about CAD programs for solid modeling in the next post as they belong to the digital phase of car design. But regarding the softwares for car design in the Styling phase, that is, those for surface modelling, the following are used:
Autodesk Alias, Autodesk Maya, Icem Surf by Catia and Rhinoceros.
If you want to specialize in 3d car design, but in the artistic or styling way, it's more advisable to learn one of these programs, especially Icem Surf or Rhinoceros.
Rhinoceros has a free trial license, and, after passing the period, it doesn't allow you to save the files, but it does allow you to continue learning. This is useful for tutorials, since their value is learning and not the resulting CAD. If you don't have previous experience in 3d design, our recommendation is to take a course or buy a book that helps you get used to the 3d design environment, just to know how to start and define a design. So, once you have a basic skill, you can start watching tutorials, buying more books or take small courses with which to gain mastery of the program, and learn different tricks, shortcuts and tools to apply to future designs.
For styling, the advantage is that the portfolio plays a fundamental role in professional development, so you can always improve by yourself.
It should be noted that with the rest of CAD programs, surfaces are also modeled, but they aren't as focused as the previously mentioned softwares. For example: Solidworks, Fusion 360, Ptc Creo, ect. But these aren't the first recommendation for someone who only wants to focus on the car aesthetics; but always linked to engineering.
Here we can quickly visualize what this type of design offers us with Icem Surf.
Here we can see a modeling example, courtesy of Artem Shkirenko (@artshkirenko), in which we can appreciate the high quality that can be achieved with this type of stylistic tools.
This design is different from the final 3D that engineers will use to design, calculate and build the car. So car design programs vary whether we're talking about surface modelling or simulating the various components of vehicles. Modeling is for visualization but isn't as directly useful in vehicle production. Even so, it's a fundamental step since it will give us the volumes and proportions of the vehicle.
This 3D modelling is similar to that used in video game design, for example, where there is no industrialized production of the vehicle. Therefore, the actual physical properties are irrelevant. It is also possible to use it to design cars for toys, R/C cars, diecast models, slot-cars, etc. Although the difference with video-game design is that it has to be aligned and consistent with engineering requirements.
This allows us to visualize in advance the design that the vehicle will have, without investing large amounts of money in the development of a functional prototype.
Augmented reality: Using virtual reality, designers review the concept in detai. Special glasses can be used for visualization, although some brands are already beginning to project themselves in holograms or on screens.
Thanks to this, even the "driving-experience" can be simulated dynamically, so that designers can better understand the design. Designers can now visually simulate different weather conditions, the vehicle environment, and details such as irregularities on the road. Technical engineering doesn't fully enter this phase, so the technical properties aren't simulated.
It's a technology that is booming, and for many manufacturers it's hard to find professionals specialized in this field, which can mean a great opportunity for engineering students.
3 - AUTOMOTIVE CLAY MODELING
Car clay modeling
After this phase comes one of the most interesting stages, the modeling of cars in clay. It's the first time that the vehicle can be displayed in full scale. Professionals in this area have often studied fine arts. They work with all kinds of utensils to mold clay such as files, scalpels, metal rollers, a knife or a small rake. Clay modeling is a truly handmade process.
Throughout this process, the modelers will rely on the sketches, the tape drawing and the computer aided designs. They will vary the curves with the adhesive tape while modifying those same curves in the car, in this way, designers obtain a greater vision of the vehicle, both in a two-dimensional and three-dimensional way.
At the beginning, ¼ scale or 1/10 scale models are made, depending on the manufacturer. Other brands can make other types of scales, for example, Lamborghini makes 1/3 scale models. These models offer for the first time a vision of what the vehicle will be like physically, this helps designers to improve the balance of proportions and lines.
Car brands like Acura implement the engineering even in the ¼ scale model phase, checking the different profiles and shapes in the wind tunnel.
Once the initial volume in clay is obtained, the chief-designer will use the masking tape to mark the different lines to separate and emphasize the different volumes. Fixed elements such as headlights and grille are also established in a much more visual way than with 3d design. These elements are called "Down the Road Graphic" and are known by the acronym DRG. This will give the modelist a greater point of reference. Then the modelist will add color and additional elements such as exhausts and spoilers to the model. Currently there is a tendency to use 3d printing to create these elements.
After this, this clay-model will be introduced to the management board, If the clay-model gets the thumbs up, then it's on to the next phase. The staff will then begin to work on the full scale model. With a milling machine, an initial reference volume is obtained on wood or high-density polyurethane, from the previously made Cad (Cas). Then the clay is added and molded, by hand. Between 2.5 and 5 tons of clay are used per model. Four to six shapers work at the same time on the same model.
Once the finished model is obtained, the different engineering departments will evaluate the model, since each one is an expert in a single subject. Due to this, the model will still undergo many changes to obtain the final version, called "Design Freeze" or "Frozen Model". Then, it's covered with thin sheets of plastic, Di-Noc or ScotchCal, to simulate the sheet metal and even the glass of the vehicle. This final version is very similar to the real production vehicle, in fact, they're sometimes displayed in auto shows giving the feeling of being a fully finished vehicle; when in fact it's a mockup. Once finished, it's digitized with a 3d scanner to transfer its measurements to a computer.
3 - AUTOMOTIVE CLAY MODELING - INTERIOR
Clay Modeling - Vehicle Interior
The interior design of the vehicle becomes increasingly important, and digitization becomes latent in the earliest stages of design. Although it can also be made in clay, this design is made separately from the final model, since the “Frozen Model” is a solid block. Creative designers work together with other people such as electronic engineers, telecommunications engineers, or ergonomics specialists. This is due to the fact that the interior cannot obey only the aesthetic sense, but it has to be functional and reach a series of technical requirements. There can be up to 50 different departments involved in the mockup, since all of them will have to validate and modify the final design.
There're departments such as haptic or kinesthetic communication, responsible for studying the perception of different sensations solely through touch. From a button panel, to the texture of the steering wheel and seats. This area is becoming increasingly important, like the HMI (user-machine interface) and the User Experience in the automotive industry.
There can be 50 different departments involved in a single design, they're in charge of fields as varied as lighting, the graphical user interface or the design feasibility, in order to ensure coherence between all the elements of the interior of the vehicle with respect to the exterior of the same.
4 - COLOR & TRIM
Color & Trim
Once the entire vehicle is modeled in clay, a specialized team takes care of the visual details, such as the choice of textures, fabrics and colors of the vehicle. There're many brands that have a complete department dedicated solely to the color of the vehicles, called Color & Trim. These departments can use between 80 and 100 liters of paint to achieve a single perfect shade. The possible textures, colors and combinations of the fabrics and leather of the car are studied in depth.
There is a team in charge of designing the patterns for the seats and the rest of the interior fabrics, such as the roof or the trunk. All these patterns are those that will be destined to the supplier for mass production. Except for the luxury models, which are still made by hand. Currently there is a greater use of virtual reality, although there will always be a place for artisan work.
Interior designers can use special HMD helmets and 3D glasses to fully visualize the interior of the vehicle, as in the previous phases.
In this phase, as a general rule, two to three years will have elapsed since the beginning of the project. Currently, the trend is to shorten these development times.
From drivingyourdream, we hope you have learned and that this post has been of interest to you. In the next post we will see the digital phase, and we will continue explaining more elements of Cad.