Cadalyst Labs Review: IronCAD 91 Nov, 2006 By: IDSA ,Mike Hudspeth
Hybrid 3D modeler makes history tree optional
IronCAD has just released v9 of its versatile 3D modeling software. Positioned to compete with midrange solid modelers such as SolidWorks and Inventor, it's a hybrid modeler—in other words, a program that can use parametric as well as explicit methodologies. IronCAD 9 can be either history-based—using sketches and constraints to control how things are constructed in a particular order—or nonhistory-based—building geometry without regard to the construction order. That choice allows users to model the forms they want virtually without regard for how the software wants to do things. Modeling can be quite freeform, but controlled when appropriate (figure 1).
IronCAD 9 can manage this double duty especially well because it's a dual-kernel program. It has its feet firmly in the ACIS camp but also in the Parasolid camp, a unique approach. The two modeling kernels usually don't get to talk to each other much, but in IronCAD 9 they work as a team and constantly query each other to make sure the job at hand is being done in the best way. If one kernel can do something better, it takes over, giving the reins back to the default kernel when it's done. That way, users get the best capabilities of both kernels. By the way, IronCAD does all this transparently. Beyond specifying the default, users never have to chose which kernel they want working.
IronCAD 9 is intended for tasks such as industrial design, where its powerful modeling capability helps to quickly generate iterative concepts; engineering and manufacturing, where accuracy and control are paramount; and product design and packaging, where ease of use is imperative. Just about everything in the program can be dragged and dropped. IronCAD 9 uses catalogs or collections of predefined geometry—features, parts and assemblies—that can be brought into a model from almost anywhere (figure 1).
Figure 1. Rendering of a machine press created using IronCAD 9.
Users can rely on the primitives that come with IronCAD 9, create their own standard parts or download parts from the Internet. If you use a standard type of screw boss all the time, you can create one and save it. It becomes something like a user-defined feature, but it's not frozen in time as is the case with some systems. Intellishapes have variable-driven properties that users can change. They can be dragged onto any face of a model. IronCAD calls that cruising, and it's actually fun to do.
In a history-based modeling system, changes can pose quite a challenge. When one feature is dependent on another, changing one feature without affecting the other can be difficult. That's not really a problem for IronCAD 9. The Smart Update function can reorder the model's history tree to accommodate changes that would freak out other systems. In-context part editing allows users to reference geometry that follows later in the history.
Again, in a history-based modeling system, users must do things in a set order. One feature is dependent on what came before it. Occasionally you'll be modeling merrily along when you find something that you should've done earlier in the history tree. When you go back to make a change, sometimes the geometry you want to constrain to is gone, because it appears later on the tree. Programs like SolidWorks won't let you reference what you want or even let you see it. Unigraphics NX lets you see it, but won't let you constrain to it—hardly a better solution. You're left with a lot of complicated reordering. IronCAD 9 avoids all that by allowing users to reference anything anywhere.
Getting It Together
Many times designers create a part and then add features at the assembly level. Perhaps you need to grind two surfaces to match or drill holes after two parts are assembled to each other. What do you do when it's decided later that the holes can be drilled in the component parts? In IronCAD 9, assembly-level features can be pushed out of the assembly into its component parts. This saves the trouble of redoing the features.
Direct-face modification puts handles on each face (figure 2). IronCAD changes only what you tell it to. It removes the affected faces from the feature tree, and you can't edit them parametrically unless you add new parameters later. The patented Triball function is used to drag the faces.
Figure 2. IronCAD 9 lets users push or pull a model one face at a time so they can get just the shape they want, without regard for what the modeling program wants.
Another good feature in IronCAD 9 is design variation, which is like a SolidWorks configuration but with a much more helpful interface. Users can explore what-if scenarios, create families of parts and even make proposed changes to a model for later perusal.
Figure 3. Assembly features can be made very smart indeed. When you add a door to a wall, the feature can know that it needs a hole cut. IronCAD 9 cuts the hole and, if you want it to, even pushes the cut down into the component wall file.
Smart Assemblies uses attachment points to automatically mate parts (figure 3) and can pull parameters from a hole to size a shaft. When users are sketching in IronCAD 9, constraints can reference faces between parts (figure 4). This capability makes top-down modeling so much easier. How many times have you needed to stretch an assembly? It's usually a lot of work. You have to stretch each individual part and hope you remembered them all. IronCAD 9 has that taken care of—Intellistretch can modify the entire assembly at once.
Figure 4. IronCAD users can create a parameter table to control any constraints on a model. Constraints can even jump between two different parts.
Almost all good 3D modelers move and copy features from one place on a model to another. In programs such as SolidEdge, users just select the features to move or copy and drag them around, dropping them at their new location. Dragging with the <Ctrl> key pressed makes a copy. IronCAD 9 is a little different. Users can cruise the feature anywhere on the model and make copies that can be linked together. Other programs call this feature instancing or an array, which is based on a parent/child relationship. Linking the features makes all the instances the same—change one and they all change. However, these shapes can be unlinked or deleted at any time without affecting the other linked features.
IronCAD 9 is a great software program for modeling designs. No matter what design discipline you work in, you'll find great value with IronCAD 9. It's not as high-profile as some other midrange modelers out there, but it's certainly worth checking out. For more information, visit the company Web site at www.ironcad.com. Highly Recommended.
Mike Hudspeth, IDSA, is an industrial designer, artist and author based in St. Louis, Missouri.
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