CAD Freeform Surface Modeling – Freeform Models – CAD Surface Models
Freeform organic shapes can present many 3D modeling challenges. In fact, some common, everyday products like machine parts, sporting goods and orthotics, as well as jewelry, toys, and hardware are often modeled using CAD surface modeling techniques.
CAD systems can easily represent geometrically well-defined shapes (circles, triangles, rectangles, and even some smooth rounded surfaces, such as car bodies; but, freeform organic shapes which are sculpted (such as jewelry or sporting goods) or shapes with complex surface data (manufacturing parts, tools and dies) are difficult to work within CAD.
Most modern CAD systems represent surfaces using a standard mathematical form: NURBS (Non-Uniform Rational B-Splines), invented in 1975 by Ken Versprille. NURBS can be used to accurately represent both analytic surfaces (e.g., spheres, cones, cylinders, and tori), and free-form surfaces, so they’re a good, but not perfect, choice as a native geometric form for CAD.
The biggest thing problem with NURBS is that they only come in one form: 4-sided. Using a standard 4-sided NURBS to build a free-form organic shape can be difficult. That’s where we come in.
We can help you create both class A and class B surfaces. Using NURBS modeling, our parametric surfacing experts work with you to perfect the details of each project. Our advanced 3D scanning and dense point cloud software give help your projects meet the highest possible standards.
We help clients in the following industries:
- Wind power
- And others requiring high accuracy
When we do organic shape modeling with NURBS, we generally take one of two approaches when we’re working with 2D sketches: (1) Start with a block and cut off what we don’t need; or (2) Start with a blank plane and add what we need. By using 2D sketches on working planes or surfaces, and extruding, rotating, sweeping, or lofting them we can create features on the 3D model.
We can also do freeform organic shape modeling by using SubDs (or T-Splines). This involves working with an initial mesh shape, then subdividing it into areas that need more detail and refinement. By pushing or pulling on its surface we can form it into the shape you need. Some of our technicians say It’s like electronic clay modeling.
Finally, if we have an original object, that is similar to the final project, we can use 3D scanning technology to create a point cloud of the object. A point cloud is a set of data points in a three-dimensional coordinate system that serves as the beginning place for the final 3D model. From the point cloud, we can convert into a mesh model in the desired CAD system, mold, and model the mesh, ultimately ending up with a final virtual model of the finished product.