3D Modeling vs 3D Rendering: The Differences Explained

Contrary to what the average consumer believes, there is a distinction between the terms of modeling and rendering in concern to computer generated imagery, wherein one is simply considered a vital portion of a CGI project while the other is essentially the finishing touches of said project.

In terms of 3D image generation, both modeling and rendering are of paramount importance, being so essential to the operation that it would quite literally not exist otherwise. This is due to the fact that both 3D modeling and 3D rendering are two parts of the same computer image generating process.

However, this leads to some confusion, especially for clients seeking out the services of a professional rendering artist or firm, causing them to request the wrong sort of service and wasting valuable time.

3D modeling refers to the sculpting of a digital object using modeling software wherein an artist or effects engineer will alter the shape of a basic object as if shaping clay, eventually ending up at their desired shape. 

3D rendering, on the other hand, is the computer generation of a finished image or scene, usually consisting of photorealistic post processing effects, one or several modeled subjects within the render, as well as a background or backdrop.

What is 3D Modeling?

3d modeling

3D modeling is the software-assisted act of sculpting a digital object for use in rendering and animation. Usually, 3D modeling involves warping and shaping interconnected nodes that shape up the outline or wire-frame of an object, oftentimes padding out the shape with triangular geometry or similar shapes in order to give the modelled object a more defined appearance.

Referred to as a 3D model or Modelled Object, the end product of 3D modeling may be incorporated into a variety of rendering uses, including that of 2D rendering, though 3D models generally look out of place in projects of the sort.

Types of 3D Modeling

Considering the fact that 3D modeling has been in use for several decades, it is by no stretch of imagination that multiple methods of creating a three-dimensional digital object are available, with certain types of 3D artists retaining a larger focus on one method over the other.

These differentiating methods are separated by the nature of which they function, making them functionally unlike, and as such are facilitated through the use of software programs that bear no relation to each other, though they may be produced by the same companies.

Vertices Polygonal Modeling

Beginning with single dimensional points, lines are drawn connecting said points as they are placed throughout a three-dimensional space, evolving from a single dimensional point to a 3D object as the lines fill out the space between these points, of which are otherwise referred to as vertices.

As the spaces between each point begin to fill up, they form polygonal shapes, creating a triangular side to the object that may be increasingly duplicated to simulate the appearance of a round edge or flat plane. 

The problem with this method of creating a round object is that it is a slightly inefficient strategy that requires ever compounding levels of computational power as each polygon is formed, eventually resulting in thousands of vertices for modern day 3d model objects that may require a powerful machine to render in a short time.

However, that is not to say that polygonal modeling is not the most common form of 3D modeling being utilized by modern day 3D artists. In fact, polygonal modeling is the primary method responsible for most forms of 3D rendering in different types of modern media, such as video games and animated movies.

Curve Modeling

Relatively uncommon in comparison to the two other forms of 3D modeling, curve modeling produces a rounded line that follows a set of points in three-dimensional space, forming arcs referred to as splines. 

Curve modeling may produce a variety of shapes varying in complexity such as patches of splines, geometric primitive shapes and other simple objects. These shapes are influenced by the “weight” or value of a given point along one area of the spline, bending the curve more rigidly towards said point as the value is raised.

Modern Digital Sculpting

The second most popular method of 3D modeling and forecasted to be the foremost some time in the future, digital sculpting is a recently developed form of 3D modeling render software split into three different subtypes.

The most frequently utilized by rendering programs is that of the displacement digital sculpting type, wherein a subdivision surface mesh is generated as the artist places new vertices along its place, shaping the model by “displacing” its edges.

Apart from the displacement method, there is also the method of volumetric sculpting based on voxel-dictated rendering, and dynamic tessellation.

What is 3D Rendering?

3d rendering

3D rendering is a fundamental component of computer image generation wherein the finishing touches of a scene or image are computed by a rendering software utilizing the hardware’s processing power.

Being a computational process that has existed for several decades, a multitude of methods and extensions have been developed by differing entities, making 3D rendering an entire subsection of computing all on its own, with specialized hardware or computer systems being built for this sole task.

In modern times, 3D rendering is utilized in a variety of consumer media and professional industries, such as in advertisements, television and movies as well as architectural demonstration or planning.

3D rendering, depending on the purpose, complexity and the particular software in use, is responsible for the majority of rendered effects in a rendered project or rendered frame, with factors such as animation, lighting, visual effects and other complex calculations falling beneath the purview of 3D rendering.

However, 3D rendering is not simply used for the production of single frames, as a sufficiently powerful enough graphical processor may produce a multitude of frames within a very short span of time, essentially creating a moving picture that appears to constantly update for the human eye. 

This is most often utilized in video games, where hundreds of rendered frames may be outputted within the space of a single minute.

Can 3D Modeling be Performed Without Rendering?

Considering the fact that 3D modeling is the act of creating a three-dimensional object for use in a rendered scene or project, it is by no stretch of imagination that not only can 3D modeling be performed without the use of rendering software, but may even precede it entirely in order to prepare a scene.

This, however, is not always applicable, as certain types of rendering software can even come with their own built-in 3D modeling software, streamlining the process and blurring the lines between 3D modeling and rendering.

It is also not uncommon for 3D modeling artists to “test” the visual appearance of their digital creations, subjecting them to rudimentary rendering conditions in order to ascertain that the object is to their desired specifications. 

Oftentimes the visual effects used in this testing are nowhere near as sophisticated or high-quality as that of serious 3D rendering, with the advantage to doing this being the high speeds at which the test may be performed.

Can 3D Rendering be Performed Without Modeling?

3D rendering cannot be performed without the presence of 3D modeling in its scenes except in a specific few circumstances wherein certain rendering effects are added to an image or similar purposes.

However, even in these particular circumstances, some level of 3D modeling may still be required so as to give the software something to utilize in its calculations. This is most often seen by the use of placeholder 3D objects that act as boundaries in a 3D rendered space, or even as lighting point sources.

The particular reasoning behind this distinction is that both 3D modeling and 3D rendering are part of the same process; namely computer image generation, with 3D modeling acting as the preceding step to 3D rendering.

As such, 3D rendering first requires the input of 3D modeling in the form of modeled objects so the rendering software may then apply its effects to said object. 

This can be seen in many slowed technological demos wherein a textured three dimensional object is first present with no sort of visual effects applied to it, and subsequently rendering software begins to add lighting, reflections, anti-aliasing and various other effects that are not normally incorporated into a 3D modeled object.

What are the Software Differences Between the Two?

While dedicated software exists for both 3D modeling and 3D rendering separately, it is not uncommon for the most popular rendering software to offer a built-in 3D modeling widget, allowing a render artist to produce, test and render a 3D scene or object entirely in the same program.

However, in the case of dedicated software, 3D modeling software is often far lighter weight, as its primary purpose is simply the calculation of points within a three-dimensional space, though this depends on the particular method of 3D modeling being performed.

And when speaking of dedicated 3D rendering software, the majority are built to be highly compatible with a variety of 3D modeling outputs owing to the fact that dedicated rendering software without a built-in 3D model converting function will serve very little purpose.

Why are 3D Modeling and 3D Rendering Used?

3D modeling and 3D rendering, at their core, are simply the visual representation of complex mathematical calculations processed through the translator of several layers of software. 

In simpler terms, this means that 3D modeling and rendering are used as they are simply a version of a computer’s most basic language; that of math.

While 3D modeling and rendering present a multitude of options pertaining to their methods, software types, features and even dedicated hardware, computer generated imagery all falls under the category of a computational process in the end.

And so, unless an alternative form of computational processing is somehow produced, 3D modeling and 3D rendering will likely be the only kind of commercially utilized image generation for the foreseeable future.


  • Unknown Author. Marketing, TOPS (2020-04-27). “What is 3D Modeling? | How 3D Modeling is Used Today”. TOPS.
  • Badler, Norman I. “3D Object Modeling Lecture Series” (PDF). University of North Carolina at Chapel Hill.
  • Manferdini AM, Remondino F. A Review of Reality-Based 3D Model Generation, Segmentation and Web-Based Visualization Methods. International Journal of Heritage in the Digital Era. 2012