3D modelling is done by artists who work on virtual 3D objects. In a games studio working environment. Film maker, designers architects etc uses 3D modelling to create animations, games, virtual models etc. There are many different methods o modelling 3D object each one of these methods has its own advantages and disadvantages. Some artists prefer one over the other because of certain properties they might like.
Polygonal modelling
A polygonal mesh is a combination of edges, faces and surfaces that combine to create a 3 dimensional object. Polygonal modelling is usually done by manipulating a simple primitive object using the tools from the 3D application that you are using to make a more complicated objects that consists of polygons and edges. Polygonal modeling is mostly used for scanline rendering and is a modeling method used for real time rendering (Rendering method used for video games). Polygonal modelling consists of using options such as subdivide and extrude to create more surfaces for 3D model from surfaces that already exist. This is also very similar to box modelling because that also consists of manipulating a 3D object to create a complicated object.
(http://www.webreference.com/3d/cararra/images/fig1_11.jpg)
I have personally used polygon modelling for my final major project. I used a 3D software called blender to create an axe from polygon modelling. To create this I simply used a backdrop image of an axe to guide me through the space of it and I just copied and moved different polygons and points to create new surfaces and manipulate the models. I used the same technique for a number of more models within the project..
Primitive Modelling
Primitive modelling is one of the most common ways on 3D modelling. This consists of combining simple primitives such as cubes, pyramids, cylinder, spheres etc. to create more complicated 3D objects. Primitive modelling is the most basic and in most cases easiest technique used by beginners, but in the right hands this technique could be used very effectively to create highly detailed models. Many 3D artists combine primitive modelling with other techniques to make 3D models since it can be very effective. Primitive modelling is less likely to be used for real time rendering applications such as video games because it can be very heavy on the hardware when rendered, This is because of its high polygon count because of the multiple geometry used in one model. So in that sense this type of modelling isn't the most effective. Because of this primitive modelling is mostly used in CAD Systems for architecture based projects since it uses no real time rendering.
The video below demonstrates primitive modelling can be used. Its set in a CAD system because of the real time rendering issue I stated earlier.
I have also used primitive modeling to make a camera using different shaped like cubes and cylinder and put them together to make it. This was a very basic model of me trying out a new software I also use the same technique mixed with other types of modelling on my final major project. I also used this same method of modeling mixed with some of the other techniques to create a final robot model for the assignment which is also shown below.
Box Modelling
The video below demonstrates box modelling in a more complicated scale. The artist uses settings such as subdivisions, extrusion, bevel and move tools to manipulate and create new surfaced to make the head.
I also have first hand experience in using box modelling to create models of different complexities, In my opinion this is the easiest method of modelling I have tried yet because of it's simplicity and the room I have for creativity. I have used this method of modelling to create simple model shown first (Tardis) which took very little time because of its simplicity and the method used.
Extrusion modelling
Extrusion modelling is done by using a 2D object to make a surface and then extruding that surface in a 3 dimensional space to produce a 3D object. This way is most useful when using a reference to to make a 3D Object. In some software like CAD this is the main way to produce 3D models. Drawing a 2D outline of the object you want to make and then use the extrusion tool to make it 3D, then the user has the ability to manipulate this object to make it look better. Polygonal modelling can be very usefull when making real life objects in 3D space true to an existing real life object. For an example If I were to make a car that already exists I can use extrusion modelling to create a 2D representation of the real car and then extrude it to get the general shape and size of the objects.
The video below briefly shows how extrusion modeling is done
The video below briefly shows how extrusion modeling is done
I have also done extrusion modeling myself to make a rifle, As you can see below . have used the first image which is a 2D image to produce a 3D model of it. to get the maximum detail I extruded the different parts of the riffle separately to get the right heights and lengths of them while extruding.
I've also used this method of modelling in prior to this course for a house plan design I've made using CAD. For the model below I've used a 2D plan for the house to extrude it and then make a 3D model out of it. I extruded different parts of the house separately to get the right sizes of each part.
Sketch modeling
Sketch modeling used by some artists mainly make more detailed models like faces and such. This is a simple form of modeling that uses the same principle as making objects with clay or sculpting. In this king of modeling the artist is provided with a block which can be sculpted or manipulated in anyway to achieve any level of detail. Sketch modelling or sculpting is mainly used by character artists to create faces and other models that has to very highly detailed but doesn't have to pinpoint accurate because most of the sculpting is usually done by hand. Sketch modeling is usually used for games and animations in the film industry and the games industry. The games industry keeps the sketch modelling to a minimum because of performance issues with lower end hardware since there can be a lot of polygons in highly detailed models. But this is widely used with animation in the film industry because it is pre-rendered so there is no real time rendering performance issues to worry about.
The video below shows an example of sketch modelling.
I also have first hand experience using sketch modelling for my final major project. I used the sculpting tool in blender to make some rocks but I used an extension in blender to lower the polygon count by deleting un-wanted extra polygons.
3D scanners
3D scanners are used to scan real life 3D objects to get them in a virtual space which then can be changed to anything the artists wants. Since these scanners and all equipment needed are expensive these are only used by researchers and other industry professionals at the moment. But there are some cheaper 3D scanners for home use but they are not as accurate as in the industry 3D scanners. This method can be sued to get accurate real life objects into a virtual space and it also can save alot of time for 3D artist when working in a project. The only bad this about this is that it will need some tweaking after the object is scans since it does not have any control of poly counts for games and how detailed its going to be. This method is almost never used in the Film industry because anything that can be scanned in as a 3D object can just be used in real life, but this could be a great way easier method to create 3D objects for games if performance isn't an issue.
(https://3dprint.com/wp-content/uploads/2014/06/itseez-scan.png)
