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Building Parts in an Assembly
When building parts in context of the assembly, you can take advantage of other parts that exist. You can copy geometry, offset from it, add sketch relations to it, or simply measure to it. In this example, geometry from Base1 creates Jaw_Plate.
Common Tools When you build parts in the context of the assembly, sketching is just like it is in part mode with the added benefit that you can see and reference the geometry of the surrounding parts. You will use Convert Entities and Offset Entities as well as dimensions to geometry.
7 Convert Entities.
Select the same face selected for the new part and click Convert Entities . This will convert all of the outer edges of the face to new sketch segments in our sketch. Each has an On Edge relation.
8 Extrude boss.
Extrude a boss to a blind thickness of 5mm. 9 Edit assembly.
Toggle off editing the component. Right-click and click Edit Assembly:
Machine_Vise.
10 Save the files.
Click Save . Click Save All in the Save Modified Documents dialog box. The Save As dialog then states:
This assembly contains unsaved virtual components which must be saved.
Click the option Save internally (inside the assembly) and click OK.
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11 New part.
Insert another new part using the face of Base2 shown.
12 Convert edges.
Use Convert Edges on the sketch face. Remove some geometry and drag open ends as shown.
13 Complete sketch.
Use offsets, lines, dimensions, and relations to complete the sketch.
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14 Extrusion.
Extrude the sketch 25mm as shown.
15 Edit assembly.
Toggle off editing the component by clicking Edit Assembly.
16 Rename part.
Right-click the part and click Rename Part. Change the name to Sliding_Jaw.
17 Save the files.
Save the parts internally.
In-Context Features
In-context Features create geometry in the active part by sketching on, converting, offsetting or dimensioning to, geometry in other component parts. The feature that is created is called an In-context Feature, a feature with external references. In this example,
Sliding_Jaw will be edited to match the other end of the vise.
Note A Through All cut only affects the part being edited.
18 Hide component.
Hide Jaw_Plate.
We do this because we want to use the geometry of Base1 for a new feature in Sliding_Jaw.
Note We can use the geometry of Jaw_Plate for the new feature in Sliding_Jaw because it is the correct shape but this is not good practice. It is better to reference the original component, Base1. It is always best to reference the original component rather than another component that uses the geometry of the original component.
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19 Edit component.
Right-click Sliding_Jaw and click Edit Part . Sketch on the outer face of Sliding_Jaw and use Convert Entities on the opposite face of Base1. Extrude 10mm as shown.
20 Offset Entities.
Start a sketch on the front face of Sliding_Jaw (select the face through the hole). Use an offset of 2mm from the hole in Base2 and create a Through All cut.
21 Edit assembly.
Toggle off editing the component by clicking Edit Assembly.
Note Using a Through All cut does not cut Base1 because it applies only to the part being edited.
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Working Outside the Assembly
Much of the construction required for a part can be done without the overhead of the assembly. Those features that do not require in-context references can be completed within the framework of the part
document.
22 Open a part file.
Right-click Sliding_Jaw and click Open Part . Add a 2mm fillet to the edges shown.
23 Offset.
Offset 3mm from the edge of the in-context circular cut and create another cut 5mm deep as shown.
24 Sketch.
Create a sketch for a boss feature from the existing geometry including an offset of 4mm.
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25 Extrude.
Extrude the sketch Up To Surface.
Note You can change the color of Sliding_Jaw or any other part to distinguish it from the other parts.
26 Return to the assembly.
Save and close the part to return to the assembly. Click Yes to rebuild the assembly and show
Jaw_Plate.
27 Insert component.
Click Insert Components and insert Vise_Screw into the assembly. Add a Concentric mate between the shaft and the hole in Base2. Add a Coincident mate between the two faces shown.
Note You can combine top-down and bottom-up assembly modeling in this manner. You do not have to create every component in-context once you start creating one component in that manner.
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28 Instance.
Add an instance of Jaw_Plate to the assembly and mate it to Sliding_Jaw as shown.
Propagating Changes
Automatically propagating changes is one of the strongest qualities of the in-context feature. In the next portion of this lesson, we will explore how a change to Base1 will affect other parts that reference its
geometry. Changes to Base1 will be transferred to Jaw_Plate and Sliding_Jaw through propagation of changes.
29 Changes.
Double-click the Extrude1 feature of Base1 and change the indicated dimension value from 70mm to 90mm. Do not rebuild the assembly yet. Double-click the Extrude2 feature of Base1 and change the indicated dimension value from 45mm to 65mm.
30 Rebuild.
Rebuild and notice that Jaw_Plate and Sliding_Jaw update to the new dimensions of Base1.
65
90
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Saving Virtual Parts as
External
In-context parts saved internally can be saved to external part files at any time. Virtual parts do not have their own files, they are included in the assembly file.
Where to Find It I Shortcut Menu: Right-click one or more virtual parts and click Save Part (in External File).
31 Save external.
Select all of the virtual parts in the
FeatureManager design tree. Right-click the virtual parts and click Save Part (in External File). Select all of them and click Same As Assembly for each one.
Click OK. 32 Symbols.
Each part is now a true part file (*.sldprt), external to the assembly. Note that the brackets ([]) have been removed but the arrows (->) remain. The arrow indicates that the part contains External References, references to geometry outside the part itself.
InPlace Mates The InPlace mates created automatically for in-context parts are there to prevent movement of the part. This is because the in-context part is attached to geometry of parts in the assembly through external
references, references that cross between parts at the assembly level.
Changing the location of the part can cause changes to the geometry that may not be desired. The effect of external references are explained in the next section, External References on page 22. The preferred method of removing them from parts is explained in Removing External References on page 27.
Replacing InPlace Mates
InPlace mates can be removed using Delete, and the part can be re-mated using standard mate techniques, optionally leaving a degree of freedom for movement. Generally this works best if the face selected for the InPlace mate is perpendicular to the direction of motion.
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Deleting InPlace Mates
When you delete an InPlace mate, a warning message appears after the confirmation dialog:
The base sketch of the part located by the InPlace mate contains references to other entities in the assembly. These references may update in unexpected ways after this mate is deleted, because the part will no longer be positioned relative to the assembly. Would you like to remove these references now? (No geometry will be deleted.)
If you click No, the InPlace mate is removed and the relations remain, including the externally referenced ones.
If you click Yes, the InPlace mate is removed and all externally referenced relations are removed.
These options can be useful with Removing External References on page 27.
External References
External References create and maintain relations between parts at the assembly level. They are commonly sketch relations, but they can also be created as sketch planes or other geometric features.
When they are working properly, external references are considered in-context. When they cannot work properly they are considered out of context and cannot update properly.
Out of Context Jaw_Plate was modeled in the context of the assembly. It is able to work properly and change through propagation of changes only while the assembly is open. We will display this behavior in this section.
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1 Save and close the files.
2 Open a part file.
Open Jaw_Plate. Because the
assembly is not open, Jaw_Plate is out of context. Therefore, any changes to Base1 are not able to propagate to Jaw_Plate. Changes to Base1 propagate through the assembly to
Jaw_Plate. The assembly must be open for this to occur.
Look at the external reference symbols. You will see the notation “->?” appended to the Boss-Extrude feature and its sketch. The ? indicates that the external reference is out of context.
Putting a Part Back Into Context
To put an out-of-context part back into context, open the externally referenced document. There is an easy way to do this.
Introducing:
Edit In Context
Edit In Context automatically opens the document that is referenced by an external reference. This is quite a time saver because you do not have to query the feature to identify the referenced file, browse to locate it, and then open it manually.
Where to Find It I Shortcut Menu: Right-click a feature with an external reference and click Edit In Context
3 Edit In Context.
Right-click the Boss-Extrude feature and click Edit In Context. The assembly is selected by the reference and opens. The references are back in context as indicated by the -> symbol in the FeatureManager design tree of the assembly.
Breaking External References
The external references established by creating parts and features in-context remain with the part. Changes to the part will appear
everywhere that the part is used; assemblies and drawings. By the same token, changes to parts that it references will also cause it to change.
The flow of changes can be stopped temporarily or permanently using the Lock/Unlock and Break options.
If you want to reuse the in-context part in another assembly, or use it as the starting point for a similar design or apply motion, you should remove the external references. By copying and editing the in-context part, you can create a duplicate part that is not tied to the assembly.
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Breaking and Locking External References
When the List External References dialog is active, there are options available to Lock All or Break All references. These options allow you to change the relationship between the in-context part and referenced files.
Lock All The Lock All button locks or freezes the references until they are unlocked at a later date using Unlock All. These changes are reversible after OK is clicked. Until the references are unlocked, changes will not propagate to the part.
When Lock All is selected, SolidWorks displays a message:
All external references of the model “Jaw_Plate” will be locked. You will not be able to add any new external references until you unlock the existing references.
The FeatureManager design tree lists the locked references with “->*” symbols. Using Unlock All later will restore the original symbols.
Break All The Break All button breaks all references with the controlling files.
Clicking the button launches a message that indicates the change is not reversible after OK is clicked.
When Break All is selected, SolidWorks displays a message:
All external references of the model “Jaw_Plate” will be broken. You will not be able to activate these references again.
The FeatureManager design tree lists the broken references with “->x” symbols. Changes will no longer propagate to the part.
Tip You can hide the “->x” symbols. Click Tools, Options, System Options, External References, and clear Show “x” in feature tree for broken external references.
Once the references are broken, they can only be listed using the List Broken References check box in the List External References dialog.
Important! Break All does not remove the external references. It simply breaks them, and once broken, they can never be fixed. Because Break All is irreversible, you should use Lock All in almost all situations.
To learn how to remove external references, see Removing External References starting on page 27.
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4 List External References.
One way to determine whether the feature or the sketch (or both) have external references is to list them. Right-click Jaw_Plate in the FeatureManager design tree and click List External Refs.The dialog below appears.
External
Reference Report
This dialog lists the following information:
I Assembly —The assembly in which the external reference was created.
I Feature — Each feature or sketch in the model that contains an external reference.
I Data — What type of relation or selection was made to create the external reference.
I Status — Whether the feature is in or out of context.
I Referenced Entity —The name of the selected edge, face, plane or loop used to generate the external reference. The syntax also lists the part in which the entity exists. Silhouette Edge of motor<1>
means that it is an edge in the first instance of the motor component.
I Feature’s Component — The component in which the external reference exists.
In this case, there are many external references
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5 Lock All.
Click Lock All and click OK. The Status changes to Locked for the feature.
The locked external reference is indicated in the FeatureManager design tree by ->*.
6 Unlock.
Click Unlock All to return to the normal setting and click OK.
Note Do not confuse the command List External References with File, Find References. In a part document, the command File, Find References only lists the name of externally referenced documents, if they exist. It does not provide feature, data, status, entity, or component information. For example, File, Find References would tell you this:
I The referenced part document for a part created using Base Part or Mirror Part.
I The assembly document for any part with in-context references.
This includes a part created using Derive Component Part, or a part that has a cavity or join feature, or a part that has been edited in the context of an assembly to reference the geometry of other components.
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Removing External References
Options like Lock All are useful to interrupt the flow of changes to an in-context part, but the best way to stop the changes permanently is to use File, Save As with the Save As Copy option to copy the part and remove the references.
Why Remove External References?
When parts are built in-context, like Sliding_Jaw, they contain references. If mates are removed or in-context parts are used in other assemblies (out of context), unexpected changes could occur. Here are some reasons why you might remove external references.
I Component Movement
The InPlace mate prevents movement and although it can be removed, the features remain in-context.
I Re-use of Data
Component parts can generally be used in multiple assemblies. If a part contains in-context references, they must be removed prior to out of context use.
Procedure In this section, the external references will be removed from a copy of the part so that it can be changed as a totally independent part, and potentially used in another, unrelated assembly, without any effect on the original assembly.
Tip Another way to prevent changes is to save the part file to another format such as IGES or STEP. Opening that neutral file in SolidWorks creates an imported solid without features that cannot be easily
changed.
1 Save a copy of the component.
Right-click Sliding_Jaw and click Open Part . Click File, Save As. The message box tells you that Save As will replace the original document with the new one in the assembly, while Save as copy will not.
Note This dialog appears only when the referenced document (the assembly) is open.
2 Save as copy.
Save a copy of the part as Free_Sliding_Jaw. Make sure to check the Save as copy option. Click Save.
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3 Derived Features.
Save and close the current documents and open Free_Sliding_Jaw. Look at the FeatureManager design tree to check for external references. You will see the notation “->?” appended to many of the features and sketches, denoting an external reference that is out of context.
In this case, the Save as copy has broken the update capability of the part but the features remain in referenced state.
To “free” this part, each of the flagged features and sketches must be edited to remove the reference and have the ability to change
independently. Note that in some cases, only the sketch is derived, not the feature itself. In these cases, both the sketch and the related feature will display the marker.
Editing the Features
It is all well and good that the external references are not active through the copy. However, what happens when we want to change the dimensions of the features in the Free_Sliding_Jaw? For example, there are no dimensions which define the size of the base feature. How can we change the
Free_Sliding_Jaw?
All features that contain the “->?” symbol can be edited to change the way in which the geometry is constrained. Although the relationships have been broken, the geometry is still created using part references.
These references can be removed by editing sketches and features in the part, which has the effect of changing the design intent of the features.
Starting with the last feature first and working up the FeatureManager design tree typically prevents rebuild errors because you fix the child features before the parent features. The features will be worked in this order:
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Strategies for Features
Different features require different approaches. Here are some common types:
I Sketch Relations - Remove external references in sketch relations and dimensions by deleting them with Display/Delete Relations.
I Sketch Relations - Remove external references in sketch relations and dimensions by deleting them with Display/Delete Relations.