3D modeling is seriously hard.
Just try to imagine your favorite coffee shop as an example: list down all the different assets that you'd need to model to animate a scene in it, and then remember you need to do this for every new scene. Even with reused assets, an animated production takes tremendous time and effort to see the day!
The people taking care of these environments and props are called hard surface modelers, and this article explores the process and techniques involved in professional hard surface modeling.
Read on to get an overview of how things work behind the scenes:
What's Hard Surface Modeling
In 3D modeling, a hard surface is anything that has been manufactured or is machine-made, unlike organic modeling that focuses on "natural" objects like humans, animals, plants, etc.
Rigid objects that don’t deform are typically done with hard-surface modeling.
Though they are made of rubber and do deform, modeling a car’s wheels would also be regarded as hard-surface modeling because they still have a smooth surface.
A model is said to be organic if it has smooth curves where the shape seamlessly transitions to another model.
Why Hard Surface Modeling Is Important
Hard surface modeling is key to create believable animated worlds. Objects like vehicles, buildings, machines, and various props that populate scenes use hard surface modeling techniques. All these elements contribute to the storytelling by providing a relatable context within which the characters evolve.
In the production pipeline, hard surface models lay the groundwork for animation sequences: rigging these objects demands that they be modeled with animation in mind, ensuring pivots and movement ranges are accurate for the scenes.
Understanding hard surface modeling is equally important because it requires a specialized set of skills and best practices that contrasts with character modeling. It involves understanding materials, reflection properties, and the way different surfaces interact in terms of physics and function: a car chase requires detailed hard surface models that can realistically simulate motion, crashes, and other dynamic interactions. Organic modeling has a similar but different approach, with different processes and techniques involved.
The Elements Of A Hard Surface
One of the key takeaways of this article is how hard surface modeling uses a different topology―the arrangement, flow, and structure of vertices, edges, and faces that make up a 3D model's surface―than organic modeling.
Good topology not only supports efficient animation and rendering but also ensures that the model can be easily rigged and textured.
Here are some key terms used to talk about hard surfaces:
- Vertices - Points in the 3D space.
- Edges - Edges are the lines connecting two vertices. Clean edge placement is crucial for maintaining high-quality surfaces that respond well to lighting and shading.
- Faces/surfaces - Ideally, 3D models predominantly use quadrilateral (quad) polygons. Quads deform predictably and are favored in animation for better subdivision and rigging. N-gons (polygons with more than four sides) and triangles can cause issues in deformation and should thus be minimized or used strategically.
- Mesh - A collection of vertices, edges, and faces that define the shape of a 3D model.
- Bevel - Beveling is the technique of creating rounded or chipped edges instead of sharp, unrealistic lines.
- Edge loops - Continuous loops of edges that follow the contours of a model. Properly placed edge loops are important for maintaining smooth deformations, especially around joints for rigging.
- Loose parts - Loose parts are separate components of a model that may not be physically connected to the main mesh but are nonetheless part of the overall structure, like screws and bolts.
- Trims - Decorative or functional edge modifications applied to give more detail to an object, like grooves, engravings, or other surface details used to break monotony.
A Typical Hard Surface Modeling Workflow
Hard surface modelers typically follow the same steps, sometimes with extra iterations to get the 3D model right:
- Gather references—Gathering references involves collecting images, blueprints, and any available materials of the object you intend to model to understand its proportions, details, and features. You look for different angles, close-up details, and technical drawings that can provide insights into how each part of the object connects and functions.
- Separate the parts - Once you have your references, the next step is to analyze the object and break it down into simpler components/parts. Being able to understand how the object is constructed greatly helps. You can then tackle each part individually to make the modeling process more manageable, but it's also important to consider how each part connects or interacts with others.
- Block-out model - The block-out is where you create a basic, low-detail version of your model using simple shapes to define the overall form and proportions and make sure everything is sized correctly and positioned accurately before adding more detail. It’s an iterative process that requires adjustments to achieve the desired proportions and relationships between parts.
- Detailing - With the block-out complete, you can refine the model and add more intricate features that define a hard surface object, like bevels, creases, edge loops, and other trims to add realism.
- Texturing - Texturing is the process of applying images (textures) to your model to create surface patterns and details like color, roughness, and metallic properties.
- Rigging - In some cases, the model is intended for animation. Rigging is creating an animation skeleton to allow the model to be posed or animated―setting up joints, controls, and any necessary constraints to have the model function correctly. For example, a car should have spinning wheels.
That's pretty much it, but 3D models can also require more edits during animation.
Modeling Techniques And Tools For Hard Surfaces
Polygonal Modeling
Polygonal modeling is a standard technique for creating 3D models out of polygons, primarily triangles and quadrilaterals. These polygons form the surface mesh of the 3D model. Artists control the model by manipulating vertices, edges, and faces.
Subdivision Modeling
Subdivision modeling creates smooth, high-resolution meshes from a low-resolution base model.
This technique is important because it simplifies workflows by allowing artists to work with simple meshes while being able to produce high-quality outputs during rendering.
Subdivision modeling starts with a low-polygon mesh and then processes it through a series of iterations where each polygon is divided into more polygons. These subdivisions lead to a higher resolution and smoother appearance, all while maintaining original proportions and details as controlled by edge loops and crease weights.
Box Modeling
Box modeling is a simple form of polygonal modeling used extensively for creating both organic and hard surface models.
Starting with a basic primitive shape like cubes (or "boxes"), the modeler extrudes, scales, and subdivides faces, edges, and vertices to gradually transform the shape into the desired model.
Kitbashing
Kitbashing is using pre-made assets to create complex structures or enhance detail on models. Artists can select, modify, and combine these "kits" to build complex models. Typically, these kits include detailed components like pipes, panels, and engines, which can be reused across different projects.
Source: BlenderNation
It's crucial for saving time and effort, especially in productions with tight deadlines. It also encourages creativity by allowing artists to quickly experiment with various combinations of existing model components.
NURBS
NURBS (Non-Uniform Rational B-Splines) create mathematically accurate curves and surfaces. This technique is common in industries that require high levels of precision, like in automotive and industrial design.
NURBS defines surfaces with control points, weights, and knot vectors. The surfaces are generated through the manipulation of these control points, which influence the curvature and shape of the model dynamically.
Conclusion
In summary, hard surface modeling is a vital skill for 3D animation that allows the creation of detailed, realistic objects, from vehicles to architectural structures. The article explored the main techniques and tools to understand how hard surface modeling works.
AI is predicted to revolutionize hard surface modeling by automating repetitive and time-consuming tasks to allow artists to focus on more creative aspects of their craft. But the expertise of skilled modelers remains indispensable: animators will always need clean topology and smart rigging to make their work easier during production. Keep creating!
