23 JANUARY, 2017
EMILE VAN DER WAAIJ, 3D ARTIST
Welcome to Introduction to Polygon Modeling
My name is Emile van der Waaij and this week’s blog entry will be written by me. So first off let me introduce myself and the role I have at Apollo journey. I recently graduated from the NHTV with a Bachelor of Science within the field of Visual art and started working at Apollo straight after. Within Apollo I fulfill the role of 3d Artist. Something that we at Apollo have noticed is that the more our customer understands how our different disciplines work and the constraints that we have to work within, the better our communication becomes. This results in quality and efficiency going up noticeably. So to start off, I will begin by explaining one of these specialties, with the goal to improve communication with our client base more efficiently. The subject we will be focusing on is 3D Polygon Modeling. Simply put: how are 3D objects created.
If you google 3d computer graphics you get a very generic answer: ” 3D computer graphics are graphics that use a three-dimensional representation of geometric data that is stored in the computer for the purposes of performing calculations and rendering 2D images” Technically this is correct, but it fails to accurately explain how 3D art functions, and the constraints that are in place.
3D modeling is simply put, the creation or recreation of an object in 3d space. Polygonal modeling is one of the methods used. To put it technically: a polygonal model exists out of points in 3D space, called vertices, those are connected by line segments (edges) to form a polygon mesh. Simply put a polygonal model is made of numerous flat surfaces that form one whole object. The reason these objects must exist out of flat surfaces instead of for example curved surfaces is because of how computers work. They draw straight lines from point to point, meaning that a curve exists out of multiple small straight lines. The amount of flat surfaces a model has (polygon count) corresponds directly to the amount of computational power needed to use it.
When starting a new model, I first must determine some important factors: What is type of product is the model meant for? Is the model meant to go in a game engine like Unity or Unreal? Does it need to be animated in the future, what is the overall quality I want to achieve, is it realistic or more stylized, does it need textures and how many, and more. After that it is important to use correct reference, this is often delivered by the client in some form, but most of the time you need to gather some extra reference. With that in hand I should be able to accurately portray that what I am going to make.
To explain all this theory better, I will use a practical example. For this example, I am going to create a simple traffic cone, because this object consists of two easy shapes. This example will explain a few basic techniques used when 3D Modelling. So, if we look at a traffic cone you can clearly see that it’s essentially made of 2 primitive shapes: a flat box with a cone on top.
There several ways to approach this. I can draw it out point by point, I can sculpt it, but those options would be too complex and time consuming for an object as simple as this. 3D Software has a lot of primitive shapes already build in that we can use. Let’s start off with the first primitive shape: the flat box. I could guess the size, but is much better to look up default sizes of a real cone and use those.
Now that we have the bottom shape we can build the cone on top. Now we need to merge these two objects into one. I cut out a hole in the top face of the cuboid and merge the bottom of the cone to that. But after that we have some vertices and faces that share the same space. Since this is all extra data that isn’t necessary and could cause some problems for the final product I am going to delete or merge the duplicates. As you can see it already resembles a traffic cone in shape.
If we compare or model with the reference we can still see a lot of difference, first off, the corners are more rounded of and smoother in the example. This is fixable by inserting some surfaces to those areas by beveling some of the edges and corners. Now we have a more complex model and you can see the polycount also rose while we did this. The polycount tells us the amount of surfaces in the model. We need to always pay attention to the polycount when modeling because the more polygons there are in a scene the heavier it becomes to render/play. Our object however is just for this example, so we shouldn’t be bothered by the polycount, but it’s still a good thing to keep it clean and only use polys where needed.
Let’s put some colour on the model. For this I will create a material. A material is a list of options that we can apply to our object that will determine how the surfaces and edges will react to light. These can have a lot options, but for now let’s stick to the colour and the reflectivity. I will create an orange and a more reflective white material. With both done I can start applying them to the correct faces. And now we can call our traffic cone done.
With the simple object I used in the example you can see one of the ways of creation in 3D art. Though this is barely scratching the surface of all the tasks and variants of 3d art, I hope you will have a more basic understanding of 3d art. In future blogs I shall be going into some more detail of the creation of certain assets, systems, or projects. I hope you enjoyed reading this, and feel free to send me subjects you’d like to read on 3d art, or questions about this blog.