What Is 3D Rendering? How to Make Realistic 3D Images

Gone are the days when exciting and visually appealing special effects were only for blockbuster movies.

Now there’s a good chance as you flip through a magazine, drive past a billboard, or scroll through social media, you’ve seen a 3D render.

The entire process can be done using 3D rendering software, which uses data from 3D models to create the render. It’s common to think of 3D rendering as a form of virtual photography because it utilizes knowledge of scene staging and lighting to produce images. 

Types of 3D rendering

3D artists can create realistic or nonrealistic image renderings.

A realistic 3D render can be of something found in the real world. For instance, a 3D artist renders the architectural interior of a new home that looks like a photograph. Or a product design image of a piece of furniture or a car. 

Source: VRender

A non-realistic 3D render can be an outline of a diagram or an object drawn as a cartoon with a more traditional 2D look.

Source: Science Behind Pixar

3D rendering vs. 3D modeling

3D rendering doesn’t exist without 3D modeling.

3D modeling is the process of creating 3D objects using specialized software. The 3D object is made by manipulating simple shapes, complex models, and polygons using 3D modeling software. The representation, called a 3D model, conveys an object’s shape, size, and texture. 

Once the model is created, 3D rendering transforms the model into an intricate, high-quality, and true-to-life image. When combined, 3D modeling and 3D rendering are two steps designers take to make computer-generated imagery (CGI).

3D modeling always comes before 3D rendering in the 3D visualization process.

How does 3D rendering work?

Designers break up 3D rendering projects into a series of steps, starting with the 3D model and transforming it into a 2D representation. Depending on the size of the project and the software the artist uses, the steps may vary. Typically, the 3D rendering process is as follows.

Before

A few steps have to happen before 3D designers can roll up their sleeves to start rendering.

• Concept: It’s always a good idea to hold a consultation or initial meeting to discuss the vision and goals of the project, the company, or the targeted audience for the image. Based on these details, it’s easier to narrow down the final version.
• Analysis: With the vision in mind, project analysis begins. This includes deciding on details like lighting, camera angles, color, texture, and environment.
• 3D model: A digital representation of the object or surface is created as a 3D model.

During

Once the model is complete, the 3D artist can start rendering. 

• Materials and texture: The designer has to consider the object’s material to create a realistic render. The artist may change the material settings and appearance to get the most realistic visual representation possible. For instance, they may go from shiny plastic to woven linen for more enhanced visuals.
• Lighting: Light and its reflections are crucial to realistic rendering. It’s all about shadows and how they make the image appear real. Without convincing lighting, the result may look fake or unnatural. 
• Details: After texture and light, the artist adds other sculpting and more details to complete the concept.
• Feedback and refining: It’s important to get the input of the client, customer, or art director so that changes can be made before the work is considered complete. 

After

Once the finishing touches are complete, one final step goes into 3D rendering.

• Delivery: The client receives the official image. How the final image is saved depends on if it’s being used for print, film, web, or video.

3D rendering techniques

The concept of 3D rendering is similar to photography. A rendering program uses a camera and points it toward an object to create or compose a photo. Then, digital lighting makes the render as detailed as possible. 

Designers employ several techniques to produce an effective 3D render that replicates how light hits objects in real life.

Real-time rendering

The real-time rendering technique is most commonly seen in interactive and gaming graphics. These images are processed from 3D data at high speed, which ensures the rapid image processing necessary for a video game moving at 60 or more frames per second.

For a high-quality render, the software for a real-time render only takes a few minutes to create a realistic scene with natural shadows. 

Rasterization

One of the first methods used for 3D rendering is rasterization, which works by treating the model as a mesh of polygons. A mesh is a collection of vertices that form the 3D object. Each vertice has unique texture and color information attached to it. Software is then used to fill in the areas with the right colors and textures based on that data.

If 3D rendering is like photography in a general sense, think of rasterization as being similar to ‘Paint by Numbers’. There’s an outline for every color you paint, which is the same concept used here.

This method for rendering is fast and still commonly used for real-time rendering of computer games and other types of simulation.

Ray casting

Ray casting creates a 3D render by casting rays onto the model from the camera's point of view. It transforms the data into a 3D projection by tracing the rays from the camera’s point of view. This is another fast technique that makes it easy for the artist to position light sources in the 3D scene correctly.

The rays are cast and traced in groups based on the data and geometric information. In ray casting, when the rays intersect an object, the object's color and brightness at that point determine the value of one pixel in the final image. This is what makes the texture, color, and light appear as realistic as possible. 

Ray tracing

Next is ray tracing, which can simulate shadows, reflections, and refractions. Ray tracing is similar to ray casting, except it’s better at depicting light. Here, the primary rays from the camera’s point of view are cast onto the 3D model to produce secondary rays. After making contact with the model, shadow rays, reflection rays, or refraction rays are emitted, depending on the type of surface in the render.

Ray tracing also produces a shadow on another surface if the surface disrupts the path between the shadow ray and the light source. While this technique is slower than ray casting, it's used to simulate how light naturally meets with objects and creates a realistic shadow.

Perspective projection

Perspective projection makes far-away objects appear smaller than objects closer to the viewer’s eye or point of view. Rendering software creates perspective projections by multiplying a “dilation constant” to place objects relative to the wanted size into the scene.

Resolution optimization

Like a classic photo, the image resolution of a 3D render is made up of pixels. The higher and denser the number of pixels per inch, the clearer, sharper, and more realistic the final image, or render, will be.

Industries using 3D rendering

While 3D rendering is becoming more popular across varying industries, here are examples of industries where you’re most likely to find 3D renders put to good use.

• Design and architecture: Architects use 3D rendered images to showcase key effects and demonstrate the strength and weaknesses of the structures before a project officially moves into the design phase.
• Real estate: 3D rendering is often used to create a virtual tour of homes for sale. High-quality renders make it easier for developers and real estate agents to sell homes while buyers can get more details of a home in real-time.
• Marketing and advertising: Digital ads and campaigns with 3D renders present the product in the most realistic way. Plus, models in the product design phase can be used on internet platforms and social networks.
• Entertainment: 3D animation has become widely used to create engaging cartoons and movies.
• Video games: Thanks to the use of 3D render drawing technology, the gaming industry’s virtual worlds have become as similar as possible to the real world. 
• Electronics manufacturing: 3D rendering allows engineers and designers to visualize the layout of a PCB design, ensuring that components fit correctly and are placed optimally for performance. 

Benefits to 3D rendering

When done correctly, 3D rendering can lead to several benefits. Some to keep in mind are:

• The ability to display multiple viewpoints, accurate lighting, and accurate performance in a graphic or image
• High-quality visual communication with clients across varying industries, which can sell a concept and lower returns if the product is sold
• Fast and accurate representation of an idea or project with high levels of detail, visual elements, and realistic lighting in both indoor and outdoor spaces
• The ability to see and show the object from different angles, which can be especially helpful for engineers and architects 
• Compared to hiring photo studios, the concept of using 3D visualization services can end up being a lower price for simple projects
• Changes to concepts and ideas can be made fast and in real time

Challenges to 3D rendering

On the flip side, 3D rendering also leads to some challenges. Some potential downsides to keep in mind are:

• The learning curve for 3D rendering, and the software that comes with it, can be steep
• To get the render as realistic as possible, the 3D model must have accurate proportions and details, which can also be challenging to perfect
• While simple images can be rendered quickly, complex action scenes for an animated film can take weeks to create
• For a simple conceptualization, 3D rendering can be cost-effective, but for a large-scale project, the process from start to finish can be thousands of dollars

Best 3D rendering software

3D rendering software takes user-generated 3D models and places them into 3D environments or images. Thanks to these tools, media developers, artists, and graphic designers can insert disparate objects and characters imported from 3D modeling software into the setting of their choice. The renders created with this software are typically navigable, scalable, and interactive.

To qualify for inclusion in the 3D Rendering category, a product must:

• Create rendered images to be used in multimedia or on various websites
• Provide users a way to insert 3D models, objects, and characters into renderings
• Have necessary features, like texturing, lighting, and wind effects to bring renderings to life
• Offer tools for manipulating and rendering various 3D environments

* Below are the top five leading 3D rendering software solutions from G2’s Spring 2022 Grid® Report. Some reviews may be edited for clarity. 

1. Unity

Unity is 3D rendering software focused on game development, creating both 3D and 2D video games, models, designs, and experiences. In addition to gaming, it’s also used by automotive, film, and architecture industries. 

What users like:

“A huge number of features and capabilities make Unity one of the best tools for game development, and it is even better than that in other areas. As a result of the direct connection with Unity's own asset store, it is much easier to identify and utilize third-party assets, which means you will spend less time searching for anything that can be used for your project and will save time during development.”

- Unity Review, Jasper S.

What users dislike:

“There are a few things I don’t like about Unity. For one, the splash screen of the games developed using the free license is watermarked with the Unity logo. Additionally, Unity does not support linking to the external libraries and it does not have a great-looking user interface.”

- Unity Review, Nabin P.

2. Blender

In addition to 3D rendering, Blender does it all – 3D modeling, animation, rigging, and simulation. This 3D creation suite also allows users to create high-quality games, edit videos, and dabble in motion tracking. With free technical and creative production means and free access to markets, Blender believes everyone should be able to create 3D content.

What users like:

“Blender is an amazing 3D software tool that enables users to build and design just about anything. The UI is pretty easy to learn and there is huge community support. You can learn just about anything you want through many different message boards and video tutorials. Being community-supported, there are updates and add-ons that happen continuously. 

One of the greatest things about Blender is that it is free. Some of the add-ons you can get will cost money but they are not necessary to have in order to use the software. They are products created by users to simplify tasks.”

- Blender Review, Dannie B.

What users dislike:

“In the recent versions, the interface has changed. On the one hand, it looks more similar to commercial 3D modeling interfaces, thus appearing more agreeable to new users. On the other hand, users can be puzzled, though, because the old interface and formats looked awkward at first but were somewhat effective and swift.”

- Blender Review, Francesco S.

3. 3ds Max Design

3ds Max Design is created for designers, civic engineers, architects, and visualization specialists who need not only a tool for 3D rendering but also 3D design, animation, and modeling. It provides users with robust modeling tools, intuitive texturing, and shading tools, giving designers full-artistic control to create professional-grade renders.

What users like:

“The layout of 3ds Max is straightforward. The use of vertex, edge, and corner tools for modeling is one of the simplest compared to other software. The pipeline (Import and Export) is also helpful in transferring your file to other 3D rendering software.

The other thing that I like the most is its integration with other 3rd party rendering engines. The software is really good for beginner modeling as it provides easy ways and tools to start with 3d modeling.”

- 3ds Max Design Review, Hitendra S.

What users dislike: 

“It is a little tricky to get used to at first. It is like learning a new language with all the buttons and rendering; you definitely need tutorials when you first start out.”

- 3ds Max Design Review, Aylin A.

4. Maya

3D artists often use Maya for their 3D rendering, simulation, animation, and modeling needs. It boasts a fast and creative toolkit to create expansive worlds, complex characters, and dazzling effects.

What users like:

“Maya gives a complete 3D package. Maya helps to create a project as exactly as you had imagined. This software is great for animation and it's easier to use features like constraints, motion trails, and attribute editors in Autodesk Maya. I am an animator but I love modeling on Maya. It's super convenient, and we can find tutorials all over YouTube. I love the fact that we can add scripts and plug-ins according to our needs.” 

- Maya Review, Salomi R.

What users dislike:

“Maya is great software but it needs a lot of resources. It’s very intensive on the GPU for rendering which makes it basically unusable on a lightweight or a portable machine. Maya also has features that are a little complicated that need past experience with 3D modeling to utilize it to its fullest.”

- Maya Review, Subrata S.

5. Keyshot

Keyshot makes it possible for users to create 3D renderings, animations, and interactive visuals with real-time ray tracing and global illumination. Thanks to a CPU-based architecture, designers can create realistic rendering using simple computers without advanced computer graphics.

What users like:

“Keyshot takes care of lightning in an easy way and lets you preview the result of your rendering before pressing the button. Being able to do short animations on the software is also great!”

- Keyshot Review, Marcelo S. 

What users dislike:

“Keyshot needs a lot of updates on its options and features to have much better quality. Some tools give you an artificial result which is not good for everyone. In comparison with some other renderers, keyshot options look basic! You can't get very realistic results without using some other software and editors.”

- Keyshot Review, Mohammad Sadra B.

Lighting is everything

Next time you flip through a magazine or drive past a visually stunning billboard, you may be able to recognize it as a 3D render. When you’re armed with the right software and understand its various methods, 3D rendering can be a beautiful thing.

Part of creating a realistic 3D render is having a 3D model with exceptional UV mapping. Learn more about giving your model some extra flair.