Guide to 3D rendering

3D rendering is the process of creating a photorealistic 2D image from 3D models. 3D rendering is the final step in the process of 3D visualisation, which involves creating models of objects, texturing those objects and adding lighting to the scene.

3D rendering software takes all the data associated with the 3D model and renders it into a 2D image. Thanks to new texturing and lighting capabilities, that 2D image may be indistinguishable from a real photograph or it may look purposefully stlylised — that’s up to the artist and the goal of the visualisation.

Although the terms “3D rendering” and “3D visualisation” may sometimes be used interchangeably, 3D rendering is actually the final stage of the 3D visualisation process. Here is a more detailed breakdown of the 3D visualisation process, which culminates with 3D rendering.

There are a number of ways to create a 3D model or an entire scene. Some sculpting applications allow you to create and shape polygons, ultimately forming a 3D asset. This type of modelling might, for instance, be particularly suited to creating organic assets — such as plants or people — as it is well suited to an artistic interpretation of somewhat irregular shapes.

Alternatives to this approach exist. Other modelling tools focus on creating edges and surfaces, rather than polygons, in a three-dimensional space. Creating 3D assets in this way allows for great mathematical precision and such tools are often used in industrial design or computer-aided design (CAD) modelling.

Or you might opt to “scan” an existing real-life object using a specialised tool — the data captured from such a scan will allow you to re-create the object in a 3D space. Or you might prefer to go the route of procedural generation, in which your software sculpts a model for you based on a set of previously established mathematical rules.

However you create your 3D model, the next step is 3D texturing.

Polygons define the shape of 3D objects, but by themselves they lack colour or surface details. Artists are able to assign a texture to every polygon in a 3D object. Textures can be simple monochrome colours or they can simulate the appearance of essentially any surface at all, from natural materials such as rock or wood to industrial metal or plastic surfaces.

A single 3D object can be made of thousands, if not millions, of polygons. The object might appear to have the modern, industrial smoothness of a kitchen blender or the rough skin of an elephant, but at its core it's still an object composed of polygons and somewhat blank surfaces. With the right 3D materials, however, it’s possible to create the illusion of 3D depth. These textures go far beyond simply adding reflectivity or colour to an object — textures can add fine details such as stitching to a garment fabric or rows of rivets along the edge of an industrial metal surface. Such details would be extremely time-consuming to create if you were to manually add them to the geometry of an object.

3D objects need to look like they exist in the real world. This is especially true for common use cases like architectural renderings and architectural visualisation, which can turn a basic floor plan into a clear vision of what's to come.

Realistic light sources make all the difference in turning a collection of polygonal objects into a space that looks real. But 3D artists generally don't paint in light or shadows themselves. Instead, a 3D scene includes settings for the direction, intensity and type of light source that illuminates the various objects.

Textures created with the Adobe Substance 3D toolset respect by default physically based rendering (PBR) principles and thus will appear realistic in all lighting conditions. So a wooden table will still appear to be wooden whether it’s placed on a sunny terrace, indoors or even deep underground.

Notably, some surfaces and materials bend light or interact with it in distinctive ways. Glass and ice are translucent, so they reflect and refract light. Light plays on the surface of water and other liquids and prisms make tiny rainbows when light hits them just so. A scene that is accurately textured and artfully lit, can appear compelling and dramatic.

Once the 3D objects have been created and textured and the environment has been lit, the 3D rendering process begins. This is a computer-driven process that essentially takes a “snapshot” of your scene, from a point of view that you define. The result is a 2D image of your 3D scene.

Rendering software can create a single image or it can render many images in rapid succession to create the illusion of real-time motion.

Rendering is not a uniform process — there are many methods that can be used such as real-time, ray-tracing and so on that can affect the quality of the rendering. To learn more about GPU and CPU capabilities, visit the Adobe 3D hardware requirement page.