2D vs. 3D: What’s the Difference?

Key Points

• 2D shapes have two dimensions — length and width — while 3D shapes have three dimensions — length, width, and height.
• 2D shapes show all of their surfaces at all times, while 3D shapes hide a portion of their surface.
• 2D shapes are easy to draw and understand, while 3D shapes are difficult to draw.
• Understanding 2D and 3D shapes helps us graphically comprehend the objects that surround us.

The difference between 2D and 3D shapes is obvious even to the most untrained eye. But not everyone understands the difference on a theoric level, which is key for manipulating both types of shapes while designing.

In this article, we will go over how we perceive dimensions and what tricks we can use to manipulate them. Plus, we’ll learn how video games and movies use 2D and 3D to create mesmerizing fantasy worlds!

2D vs. 3D: Side-by-Side Comparison

2D vs. 3D: What’s the Difference?

2D and 3D shapes primarily differ in the number of dimensions they have.

Length, width, and height are the three dimensions (3D) that a shape can have in the real world. In the case of 2D shapes, they only have length and height dimensions, meaning that they will often seem to be “flat” representations of 3D objects.

2D and 3D shapes are essential to represent any kind of real-life object, and combining them can achieve incredible designs. We can use all three dimensions to do 3D modeling (alive or inanimate) and then, with 3D printing, bring them to life.

In the next section, we will define each of these concepts and talk about their most important characteristics.

What is 2D?

2D, or two-dimensional, refers to shapes that only have length and width as dimensions. Usually, these shapes are flat and lack depth. Some tricks and illusions can overcome this deficiency, as we will see later. 

The edges of a 2D shape are lines defined as the X-axis and Y-axis, which give mathematical precision when determining the measurements of a shape.

But there’s one problem. Our vision gives us the ability to perceive the depth of field in everyday life — which is why 2D objects can be “unnatural.” Thus, 2D shapes are not the best option to represent real objects.

Yet, some techniques help us understand depth in 2D objects and images. A clear example is that of geographic maps, where the height of the terrain follows a color scale. The same occurs in river maps and representations of the ocean.

With all its limitations, 2D design has been pushed to its limit by game designers. Famous titles like Tekken and Street Fighter have built a legacy on two-dimensional combats.

Defining 3D

3D shapes have three dimensions: length, width, and high. We can measure all the objects of our daily life using these three parameters.

We perceive our reality in a 3D way. Every object around us has the three quantifiable dimensions that we named earlier. Even the screen you’re reading this on uses light and shadow to simulate a depth effect!

When designing 3D shapes with exact measures, we can use the X-axis, Y-axis, and Z-axis. These are the mathematical values corresponding to length, width, and height.

Cubes, cylinders, and prisms are some of the most known and essential 3D figures. At all times, however, these shapes hide a part of their surface. This is a crucial concept for 3D shapes — no 3D object can show all of its faces at the same time.

In design, we can use the three dimensions to create a wide variety of products. 3D computer graphics, 3D modeling, and 3D printing are some areas of work that take advantage of these parameters. 

For example, we can design 3D models using Blender. This free and open-source software allows us to create and design digital models of any object we can imagine. 

These models can stay in the digital realm and serve as design or animation assets. Or, we can print and bring them to life using a 3D printer. 

How Does 3D Modeling Work?

Using length, width, and high we can take measures of any object that to make an accurate digital representation. We call this process “modeling,” in which we use vertices, polygons, and other shapes to compose the models. Each shape has a series of points that can be mathematically measured with software specially designed for that task. 

The actual modeling occurs when a collection of points are connected. These points form 2D shapes like triangles, lines, and squares. The more points we have, the more details our model will have.

There are point collections available online to try out 3D modeling for ourselves. With adequate hardware, we can even scan real-life objects to get a realistic digital 3D representation.

As we saw before, we can apply these same principles using a program like Blender. But don’t be discouraged if it seems too overwhelming! There are several other 3D modeling programs to try out.

2.5D Explained

Video game developers use the 2.5D (two-and-a-half dimensions) as an alternative to creating gameplay scenarios.  

Usually, these games are designed and rendered in 3D environments. But the gameplay is restricted to two dimensions only. So, 2.5D games appear to be 3D — but in reality, they trick the player’s perspective to simulate that third dimension. 

This technique is useful to generate scenes with lots of models (like vegetation and crows because it saves processing power).

Doom, Duke Nukem 3D, and Super Mario Kart are some well-known classics that use this technology. 

2D vs. 3D: 6 Need-to-Know Facts

• 2D shapes only have two dimensions, length, and width. By contrast, 3D has three dimensions: length, width, and height. 
• 2D shapes are flat and lack depth. We can perceive depth in 3D shapes, but there is always a hidden portion we can’t see.
• With 2D shapes, we can draw simple models, maps, and graphics with a lot of detail. 3D is useful for simulating digital models of real-life objects. 
• We can use Blender, a free and open-source software to design digital 3D models. In this process, called 3D modeling, we use vertices, polygons, and 2D shapes to create point collections of any kind of object.
• In the world of video games, we have famous 2D titles like Tekken, Mortal Kombat, and Cuphead.
• 2.5D (two-and-a-half dimensions) are 2D designs rendered in 3D environments.

Wrapping Up

We’ve learned that 2D shapes have length and width. 3D shapes are a bit more complex, with length, width, and height as dimensions.

We can use 2D shapes to draw flat figures, maps, graphics, and more. We can sort out the lack of depth using some tricks and techniques. For example, maps use a color code to define the terrain height variations.  

3D modeling is a crucial feature of modern digital design. It’s the first step for creating 3D printing products. 2D and 3D shapes are part of our daily life. Understanding them gives us tools to graphically comprehend the objects that surround us.

The image featured at the top of this post is ©gualtiero boffi/Shutterstock.com.