Wiley SolidWorks 2009 Bible Part 6 ppt

371 Editing and Evaluation 11 If two adjacent features are to swap places, it generally does not matter whether you move one fea- ture up the design tree or you move the other one down. However, there are isolated situations that are usually created by the nested, absorbed features discussed earlier, where one feature can- not go in one direction, but the other feature can go in the opposite direction, achieving the exact same result. If you run into a situation where you cannot reorder a feature in one direction even though it appears you should be able to, try moving another feature the other direction. Reordering Folders There are times when, regardless of which features you choose to move and of which direction you choose to move them in, you are faced with the task of moving many features. This can be time- consuming and tedious, not to mention have the potential to introduce errors. To simplify this pro- cess, you can put all of the features to be moved into a single folder, and then reorder the folder. Keep in mind that the items in the folder need to be a continuous list (you cannot skip features), and you can only reorder the folder if each individual feature within the folder can be reordered. BEST PRACTICE BEST PRACTICE Folders are frequently used for groups of features that go together and that may be suppressed or unsuppressed in groups. You can also use folders in assemblies. Folders are frequently used for the mass of cosmetic fillet features that are often found at the end of design trees for plastic parts or for groups of hole features. To create a folder, right-click a feature or a selected group of features and select Add to New Folder. Folders should be renamed to have a name that helps identify their contents. You can reor- der folders in the same way as individual features. When you delete a folder, the contents are removed from the folder; they are not deleted. You can add or remove features to or from the folders by dragging them in or out. If a folder is the last item in the FeatureManager, the next feature that is created is not put into the folder; you must place it in the folder manually. You cannot drag features out of a folder and place them immedi- ately after it, because they will just go back into the folder. If you want to pull a feature out of a folder and place it after the folder, there must be another feature between the feature that you are moving and the folder. However, you can pull a feature out of the folder and place it just before the folder. Using the Flyout FeatureManager The Flyout FeatureManager resides at the top-left corner of the graphics window, and was intro- duced when SolidWorks began to consolidate floating dialog boxes into the PropertyManager win- dow. The PropertyManager goes in the same space as the FeatureManager, and is sometimes too big to allow this area to accommodate both managers in a split window. 372 Building Intelligence into Your Parts Part II The Flyout FeatureManager enables you to select items from the design tree when the regular FeatureManager is not available because it is covered by the PropertyManager. It usually appears collapsed, so that you can only see the name of the part and the part symbol. To expand it, click the plus icon next to the name of the part in the Flyout FeatureManager. You can use the Flyout FeatureManager in parts or in the assembly. However, you cannot use the Flyout FeatureManager to suppress or rollback the tree. CROSS-REF CROSS-REF Other functionality and limitations of the Flyout FeatureManager that relate to its function in assemblies can be found in Chapters 12 to 15. You can access the settings for the Flyout FeatureManager at Tools ➪ Options ➪ FeatureManager ➪ Use Transparent Flyout FeatureManager in Parts/Assemblies. You may prefer not to work with the flyout FeatureManager. If this is the case, you can use the detachable PropertyManager instead. Detaching the PropertyManager removes the need for the fly- out. I often dock the detachable PropertyManager where the flyout FeatureManager would go. The main advantage of using the detachable PropertyManager instead of the flyout FeatureManager is that with the detachable PropertyManager you don’t have to locate features in the FeatureManager that were already in view. Figure 11.6 shows the difference between the flyout FeatureManager on the left, and the detach- able PropertyManager on the right. My preference is clearly the detachable PropertyManager. When you use this, everything is predictable, and you don’t have to go hunting for features that were listed right in front of you when you do something that opens a PropertyManager. I usually decrease the overall size of the SolidWorks application window, and place the PropertyManager to the left of the SolidWorks application. This works best on a wide aspect monitor. If you use a small monitor or a normal aspect monitor, using the Auto Collapse option with the PropertyManager docked to the right of the FeatureManager (where the flyout FeatureManager would otherwise go) is also a good option. You may correctly ask “what’s the difference?” The difference is that when you do something like editing a sketch plane, the current state of the FeatureManager is covered over and replaced by the PropertyManager. You may have had the new plane you wanted to use in view. Especially with long FeatureManagers, in both parts and assemblies, when the flyout appears, you have to again scroll to find the plane that was right in view. This has been a problem since SolidWorks started employing the PropertyManager many releases ago. However you use the detachable PropertyManager, I think you will find it an improvement over the flyout. 373 Editing and Evaluation 11 FIGURE 11.6 Comparing the flyout FeatureManager with the detachable PropertyManager Summarizing Part Modeling Best Practice This section is a summary of best practice suggestions for modeling parts. Best practice lists are important because they lay the groundwork for conservative usage of the software, which is helpful for new users and users who are trying to experiment with the limits of the software. I believe that it is only after you respect the rules and understand why they are so important, that you know enough to break them. However, best practice lists should not be taken too seriously. They are not inflexible rules, but conservative starting places; they are concepts that you can default to, but that can be broken if you have good reason. 374 Building Intelligence into Your Parts Part II n Always use unique filenames for your parts. SolidWorks assemblies and drawings may pick up incorrect references if you use parts with identical names. n Using Custom Properties is a great way to enter text-based information into your parts. Users can view this information from outside the file by using applications such as Windows Explorer, SolidWorks Explorer, and Product Data Management (PDM) applications. n Learn to sketch using automatic relations. n Use fully dimensioned sketches when possible. Splines are often impractical to fully dimension. n Limit your use of the Fixed constraint. n When possible, make relations to sketches or stable reference geometry, such as the Origin or standard planes, instead of edges or faces. Sketches are far more stable than faces, edges, or model vertices, which change their internal ID at the slightest change and may disappear entirely with fillets, chamfers, split lines, and so on. n Do not dimension to edges created by fillets or other cosmetic or temporary features. n Apply names to features, sketches, and dimensions that help to make their function clear. n When possible, use feature fillets and feature patterns rather than sketch fillets and sketch patterns. n Combine fillets into as few fillet features as possible; this also allows you to control fillets that need to be controlled separately, such as fillets to be removed for Finite Element Analysis (FEA), drawings, and simplified configurations; or added for rendering. n Create a simplified configuration when building very complex parts or working with large assemblies. n Model with symmetry in mind. Use feature patterns when possible. n Use link values or global variables to control commonly used dimensions. n Do not be afraid of configurations. Control them with design tables where there are more than a few configs, and document any custom programming or automated features in the spreadsheet. n Use display states when possible instead of configurations. n Use multi-body modeling for various techniques within parts; it is not intended as a means to create assemblies within a single part file. n Cosmetic features — fillets, in particular — should be saved for the bottom of the design tree. It is also a good idea to put them all together into a folder. n Use the setting at Tools ➪ Options ➪ Performance ➪ Verification on rebuild in combina- tion with the Ctrl+Q command to check models periodically and before calling them “done.” The more complex the model, or the more questionable some of the geometry or techniques might be, the more important it is to check the part. n Always fix errors in your part as soon as you can. Errors cause rebuild time to increase, and if you wait until more errors exist, troubleshooting may become more difficult. 375 Editing and Evaluation 11 Using the Skeleton or Wide Tree Approach S olidWorks is not the first parametric modeler to challenge the linear logic of genealogical analy- sis. The users of software like Pro/ENGINEER are responsible for developing many of the con- cepts and best practice techniques that SolidWorks users use today. NOTE NOTE The term Skeleton in Pro/ENGINEER has a different significance than the way it is being used here. SolidWorks does not have any feature or function named “skel- eton.” The term is just being used to refer to a set of sketches, planes, axes, and reference points used to lay out the major faces and features of a part. The SolidWorks Help files, tutorials, and training curricula have encouraged users in some respects to take a “fast and loose” approach to modeling, which lends itself best to simple models that are not changed frequently. Little thought is given to the structure of the part; the focus is on the final shape. The main consideration seems to be the simplest way to do something, or how it could be done rather than how it should be done. This mentality fit well with the initial several releases of the SolidWorks software, which at that time was marketed as being simple and fast. The software has progressed immensely since those days. It is now entirely plausible to create complex castings and plastic parts with many hundreds of features, weaving in and out of surface and solid techniques, multi-bodies, and external references. This is a far cry from the typical tutorial or training part, which still tend to have fewer than 15 features, half of which may be fillets. With the simpler parts, you hardly give a thought to parent/child relationships, rebuild times, or the consequences of continued n Do not add unnecessary detail. For example, it is not important to actually model a knurled surface on a round steel part. This additional detail is difficult to model in SolidWorks, it slows down the rebuild speed of your part, and there is no advantage to actually having it modeled (unless you are using the model for rapid prototype or to machine a mold for a plastic part where knurling cannot be added as a secondary pro- cess). This is better accomplished by a drawing with a note. The same concept applies to thread, extruded text, very large patterns, and other features that introduce complex details. n Do not rely heavily on niche features. For example, if you find yourself creating helices by using Flex/Twist or Wrap instead of Sweep, then you may want to rethink your approach. In fact, if you find yourself creating a lot of unnecessary helices, then you may want to rethink this approach as well, unless there is a good reason for doing so. n File size is not necessarily a measure of inefficiency. n Be cautious about accepting advice or information from Internet forums. If you are the CAD Administrator for a group of users, you may want to incorporate some best practice tips into standard operating procedures for them. The more users that you have to man- age, the more you need to standardize your system. 376 Building Intelligence into Your Parts Part II making changes that cause a feature to fail, because the whole part can be rebuilt from scratch in ten minutes anyway. This is because the people who know the software best were doing brief sales demo vignettes and small models that could be finished before the students fell asleep. SolidWorks users have traditionally been taught to build each feature linearly, on top of the one that came before. This is the genealogical equivalent of each generation having a single child, and then that child having a single child, and so on. The family tree, or FeatureManager, winds up looking like a long staircase, with each generation related only to the generation immediately before it. In the SolidWorks world, this creates long, linear, daisy-chained relationships between consecutive features. It turns out that even though this has been hailed as the pinnacle of associative, parametric, history- based modeling, it is not really such a great idea, especially as the parts begin to get more complex. When each feature is dependent upon the one before it, all of the features must be solved in a par- ticular order, and if one feature fails, so do all of the features that come after it. This also slows down the rebuilding process. Especially as we move into the age of parallel multi-threaded processing, a linear set of commands or features must be executed in order one after the other, and there is really little room for parallel processes. The sophistication of the documentation provided with SolidWorks software has not kept pace with the sophistication of the software itself, which I suppose is why you are reading this book rather than the help files provided with the software. The documentation is still based on the simple scenarios, and the advanced user is left to figure things out on his or her own. As the software gets more sophisticated, the models created with the software can get more sophis- ticated, and the methods used to build the models must also get more sophisticated. It’s time to leave the linear modeling approaches behind. Rather than using a linear daisy-chain modeling scenario, it is better practice to base features on entities that are less likely to fail or change in such a way that dependent downstream features also fail. In earlier chapters, I have already suggested that you make sketch relations to other sketches when possible instead of model edges for this very reason. Taking that scenario one step further, what if a handful of sketch and plane features were used to centralize control of all of the rest of the features? What if every feature, to the extent possible, related back to these “skeleton” features? Features such as fillets, shell, and draft by design require selections from solid geometry, but other features, such as any feature created from sketches, could be made with only reference to those original skeleton sketches and planes. The parent/child rela- tionship would look very different for a model made in this way. Instead of looking like a long stair- case, this tree would look more like a tree that gets wide very quickly. There would be fewer “generations,” but each generation would be more populated. The first thing to notice is that errors in features at the top of the tree do not cascade down the tree as they do in the “stairstep” model. Second, it is always much easier to find how a model is con- structed, because all the reference geometry used to build it is set up in the first few features. This scenario also has the potential to make better use of multi-threaded processing because the logic is less linear and more parallel. 377 Editing and Evaluation 11 Using Evaluation Techniques You can use evaluation techniques to evaluate geometry errors, demonstrate the manufacturability of a given part, or to some degree to quantify aesthetic qualities of a given part, or section of a part. I discuss evaluation techniques here because the design cycle involves iterations around the combi- nation of evaluate-edit-evaluate functions. I discuss the following techniques in this section: n Verification on rebuild n Check n Zebra Stripes/RealView/Lights and specularity n Curvature display n Deviation analysis n Tangent edges as phantom n SimulationXpress Many of these techniques apply specifically to plastic parts and complex shapes, but even if you do not become involved in these areas of design or modeling, these tools may help you to find answers on other types of products as well. Verification on rebuild Verification on rebuild is an option that you can access through Tools ➪ Options ➪ Performance ➪ Verification on rebuild. Under normal circumstances (with this setting turned off), SolidWorks checks each face to ensure that it does not overlap or intersect improperly with every adjacent face. Each face can have several neighbors. This option is shown in Figure 11.7. FIGURE 11.7 The Verification on rebuild option With the setting turned on, SolidWorks checks each face with every other face in the model. This represents a better check than with the setting off, and a greatly increased workload. The switch is off by default to prevent rebuild times from getting out of control. For most parts, the default set- ting is sufficient; however, when parts become complex, you may need to select the more advanced setting. 378 Building Intelligence into Your Parts Part II If you are having geometry or rebuild error problems with a part and cannot understand why, then try turning Verification on and pressing Ctrl+Q. Ctrl+Q applies the Forced Rebuild command, and rebuilds the entire design tree, whether or not SolidWorks determines that it is needed. Ctrl+B, or the Rebuild command, only rebuilds what SolidWorks determines needs to be rebuilt. If you see additional errors in the design tree that were not there before, then the combination of Verification on rebuild and Forced Rebuild has worked. If not, then your problem may be else- where. You still need to fix any errors found this way. PERFORMANCE PERFORMANCE For speed reasons, it is normal practice to turn Verification on rebuild off, and to use it selectively to check models with potential errors. The type of speed degrada- tion that you can see is in the 10-percent to 60-percent range. Some of the performance degrada- tion as relates to patterns is documented in Chapter 8. Check Check is a tool that checks geometry for invalid faces and other similar geometry errors. It is also often used to find open edges of surface bodies, short edges, and the minimum radius on a face or entity. I usually apply the Check tool before turning on the Verification on rebuild option. The Check tool points to specific face or edge geometry (not features or sketches) that is the cause of the problem. When it finds general faults the locations that the Check tool points to may or may not have something obvious to do with a possible fix. Much of the time, the best tool for tracking down geometry errors is the combination of experience and intuition. It is not very scientific, but you come to recognize where potential problems are likely to arise, such as attempting to intersect complex faces at complex edges. Figure 11.8 shows the Check Entity dialog box. FIGURE 11.8 The Check Entity dialog box 379 Editing and Evaluation 11 Reflective techniques Evaluating complex shapes can be difficult. Subjective evaluation is typically personal, and requires an eye for the type of work you are doing. Objective evaluation requires some sort of measurable criteria for determining a pass or fail, or it enables you to assign a score somewhere in the middle. One way to subjectively evaluate complex surfaces, and in particular the transitions between surfaces around common edges, is to use reflective techniques. If you look at an automobile’s fender, you can tell whether it has been dented or if a dent has been badly repaired by seeing how the light reflects off of the surface. The same principle applies when evaluating solid or surface models. Bad transitions appear as a crease or an unwanted bulge or indentation. The goal is to turn off the edge display and not be able to identify where the edge is between surfaces for the transition to be as smooth as if the whole area were made from a single surface. Zebra Stripes Zebra Stripes can be activated one of two ways, through the menus at View ➪ Display ➪ Zebra Stripes, or from a toolbar button on the View toolbar. The technique that was really made for analyzing complex shapes is Zebra Stripes. This places the part in a room that is either spherical or cubic, where the walls are painted with alternating black-and-white stripes (although you can change the colors and the spacing of the stripes). The part is made to be perfectly reflective, and the way that the stripes transition over edges tells you something about the qualities of the faces on either side of the edge. Four conditions are of particular interest: n c0 = faces contact at edge n c1 = faces are tangent across edge n c2 = curvature of each face is equal at the edge and the transition is smooth n c3 = rate of change of curvature of each face is equal at the edge The Zebra Stripes tool can only help you identify c0, c1, and c2, and only subjectively. This feature is of most value between complex faces. Figure 11.9 illustrates how the Zebra Stripes tool shows the differences between these three conditions. Notice how on the Contact-only model, the Zebra Stripe lines do not line up across the edge. On the Tangent example, the stripes line up across the edges, but the stripes themselves are not smooth. On the Curvature Continuous example, the stripes are smooth across the edges. The part shown in Figure 11.16 is a surface model, and can be found on the CD-ROM with the filename Chapter 11 Zebra Stripes.sldprt. TIP TIP You should rotate the model a lot when you are using the Zebra Stripes tool. Changing the density of the lines can also help, as can increasing the image quality (Tools ➪ Options ➪ Document Properties ➪ Image Quality). Turning off the edge display may also help. [...]... usually solved before the part locations, but when the plane is dependent on the part location, the plane has to be solved after the part If a part is then mated to the plane, you are beginning to create a dependency loop, such that the plane is solved, followed by the part, then the plane again because the part has moved, and then the mate that goes to the plane has to resolve the part If you are a bit... individual parts You should not confuse assembly features with in-context features In-context features are created in the assembly with a reference between parts, but the sketch and feature definition are in the part itself Starting with SolidWorks 2009, features created in the assembly can be propagated to reside in the affected parts Component patterns Component patterns can pattern either parts or... suggestions and tips for efficient workflow Chapter 16, the in-context chapter, is particularly important for SolidWorks users from many different fields who need or want to make parametric relations between parts A lot of erroneous information floats around the SolidWorks community on this topic, and this chapter helps you separate the helpful information IN THIS PART Chapter 12 Building Efficient Assemblies... are all open at the same time CROSS-REF In-context references are discussed in depth in Chapter 16 When one part drives another part in this way, the assembly must also be open to drive the relationship If just the two parts are open individually, then changing the driving part does not update the driven part; because the relationship was created in the context of the assembly, the assembly must also... chapter (Chapter 16) When you create a reference between parts in an assembly, the assembly needs to remember which parts are involved in the reference, and what the spatial relationship between them is The parts also need to remember which assembly was used to create the relation because the parts are positioned in the assembly, and the reference has meaning only with regard to a particular relative... outside of the part This has file management implications because you must maintain the names of the files so that they always recognize the other file involved in the external relation In-context means that one part has a relation to another part in positions determined by an assembly So in this case, the in-context external reference can only be solved if the original part, the referenced part, and the... SimulationXpress interface is applied as a SolidWorks material, complete with RealView, if applicable Restraint You can apply restraints to the part The restraints are limited to Fixed for the faces that are selected Figure 11.14 shows the interface and the restraint symbols on the part FIGURE 11.14 Applying restraints 383 11 Part II Building Intelligence into Your Parts Load You can apply loads to faces... the Save As command, using SolidWorks Explorer, or using Windows Explorer It also includes redirecting the assembly to the new part name, as well as renaming the assembly using each of these techniques If the assembly can find the part and recognizes the part as the one that it is looking for, then the equation will work Some of the methods named previously for renaming parts are not recommended; for... sketch for either the in-context part building or simply part positioning, the main advantage that it offers is having a single driving sketch that enables you to change the size, shape, and position of the parts You can use as many layout sketches as you want, and you can make them on different sketch planes This enables you to control parts in all directions 401 12 Part III Working with Assemblies... that you give up dynamic assembly motion To move the parts, you have to move the sketch The part does not move until the sketch is updated If you need to combine layout functionality with dynamic assembly motion, see the Layout feature in Chapter 16 Virtual components Virtual components are covered in more depth in Chapter 16 Virtual components are parts that are created in the context of the assembly, . reason. 374 Building Intelligence into Your Parts Part II n Always use unique filenames for your parts. SolidWorks assemblies and drawings may pick up incorrect references if you use parts with identical names. n. the name of the part and the part symbol. To expand it, click the plus icon next to the name of the part in the Flyout FeatureManager. You can use the Flyout FeatureManager in parts or in the. more you need to standardize your system. 3 76 Building Intelligence into Your Parts Part II making changes that cause a feature to fail, because the whole part can be rebuilt from scratch in ten