3D modeling and rendering for the rest of us

Automotive Design & Production, Sept, 2004 by Lawrence S. Gould

WHAT'S THE PROBLEM?

Car bodies, wheels, stick shifts, and so many other things are not simply assorted radii and straight lines. Instead, these objects are free-form shapes, which are particularly difficult to create/design in the world of parametrics. It is these shapes that Rhino excels at creating. Rhino, from Robert McNeel & Associates (Seattle, WA), is an extremely inexpensive, Windows-based, free-form 3D modeling program that handles non-uniform rational B-spline (NURBS) curves, surfaces, and solids. It also supports non-manifold geometry and polygon meshes. Designers can even edit surfaces based on how they reflect light, not just on some number. Company officials like to say that Rhino can go beyond high-school geometry, beyond straight lines and radiuses.

WHAT DOES RHINO DO?

With conventional solids modelers, you pretty much start with some profile, add 2D or 3D curves, and eventually get to a solid. In Rhino, you can join a bunch of surfaces together to make a solid. Or, you can take a solid, extract parts of it, and then edit those parts as if they were a surface model. Or, just start a design from scratch. In all cases, you wind up with a valid solid model that you can manufacture. Because it doesn't use parametrics, you can create shapes and solids that you otherwise couldn't create in conventional solids modelers.

THIS IS DIFFERENT?

Well, Rhino also tends to be a bit different in the "price point." It costs $895 per seat. At this price, people who need a freeform design package just go out and buy it. Small design studios find it well suited to their needs, especially because Rhino supports a slew of CAD file formats, including IGES and STEP. This lets designers successfully transfer their solids information from the low-priced-per-seat Rhino to the more-expensive CAD, engineering, renderer, and visualization tools used further up the product collaboration chain. This is why you'll often find Rhino co-existing with other solids modelers.

A lot of designers in the automotive industry use Rhino early in the design process for generating, exploring, and refining shapes, not for engineering them. In fact, Rhino doesn't have all the engineering functions one has to wade through when using other solid modelers. Designers are also buying Rhino because they need something portable and inexpensive that can handle 3D information.

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WHAT ARE THE ADD-ONS?

Rhino is available with plug-ins for CAM and for specific industrial design applications. Two plug-ins worth noting for automotive are Flamingo and Penguin, both rendering tools. Flamingo provides high-end, photorealistic ray-tracing/radiosity rendering. (The Rhino/Flamingo bundle costs $1,195.) Penguin ($195) is more for cartoon-like, watercolor, or freehand sketch-type renderings. A third plug-in, Bongo ($295 until October 31, 2004), gives designers the means to create simple animations using keyframe tools common in high-end animation packages.

WHAT'S THE TECHNOLOGY BASIS?

Rhino started in 1992 as an AutoCAD plug-in. The latest version, Rhino 3.0, is a complete rewrite. Mathematicians on-site can change the kernel--a full surface and solid kernel--as needed. The software runs on ordinary Windows desktops and laptops (256 MB RAM or more is recommended), and it takes advantage of OpenGL graphics cards.

WHAT DOESN'T RHINO DO?

Rhino does not currently support line weights, line types, plotting, sheet size, and things like that typically found in 2D CAD packages. However, there's a third-party plug-in that provides those functions.

WHAT ELSE IS THERE TO KNOW?

Rhino was the exclusive design software for the 2054 model-year Lexus ... in the movie Minority Report.

By Lawrence S. Gould, Contributing Editor