Clearance Analysis in NX

What will be covered in this workshop is as follows:• Overview

• Clearance Sets

• Basic

• Advanced

• Clearance Browser

• Analysis Reports

• Properties

• Perform Analysis

Overview

The Assembly Clearance function performs a clearance check between solids, sheets and faceted bodies. Clearance Analysis is utilized to identify when parts are too close to each other. This may be the result of an actual interference condition - where one part penetrates into another, or a clearance zone violation - where two parts are closer together than the specified clearance distance.

 It is important to note that the UG clearance analysis tool will identify all clearance zone violations. You should review each of the violations to see if it is really undesirable. Faceted reps may also lead to "false alarms".

* Please note that if you remove components from an assembly file that were used in a clearance check, the reports interference information will be cleared within the assembly file. Interference Types

No Interference - the distance between the objects is greater than the clearance zone

Hard Interference - the objects intersect each other.Soft Interference - two objects are situated such that the minimum

distance between the bodies is less than the clearance zone, but the objects do not touch

Touching Interference - two objects are touching but do not intersect each other Containment Interference - one object is completely contained within another object

Perform Analysis performs the clearance analysis on the current clearance set. When the analysis is complete, the program displays the results in the Clearance Browser.Selecting Perform Analysis before a clearance set is defined, displays the Clearance Properties dialog so the user can define a clearance set on the fly.

Clearance Sets

Initially the only two options under Clearance Set are the “Set and New”.

Set allows you to open a previously saved Clearance Set and New allows you create a new set.

Once a set is opened and you navigate back to the Clearance Set menu, you’ll have additional options. You can Copy the Clearance Set which will make a duplicate of the set. Initially it gives it the same name, but adds a numeric number at the end. Please note that you can change the name then or later. You also have the ability to Delete the set. Which ever set is opened, will be the set that gets deleted. And last is Properties which takes us to the Clearance Properties Menu and the next slide.

Clearance Set Name allows you to define the name for the clearance set that is being created. The name of "SET" followed by a number is the default.The Clearance Set Type option defines how the clearance objects are selected. The default and typical is Component type and setting it to Body should only be necessary if there are components made up of more than one solid body.

Basic Clearance Properties

Lists to CheckBy default, the analysis runs in One List mode. In this

mode, NX checks every included object against every other included object.

Using the Two Lists mode, you define two groups of objects. NX checks every object on list 1 against every object on list 2. It does not check any object on list 1 with any other object on list 1, and the same goes for list 2. Two Lists mode can be useful for checking two subassemblies against each other. The number of component pairs in Two Lists mode is equal to the number of components in List 1 multiplied by the number of components in List 2. This usually provides a much smaller set of pairs to check than One List mode.

NOTE: Using Two Lists is the preferred method.

Show will display what currently included in the list selected.

Selection Methods when adding components to a list

Default Clearance Zone

The Default Clearance Zone is the minimum distance between objects (any positive value). If the minimum distance between any two objects is less than the default clearance zone, a soft interference is reported.

Analysis Mode

This option allows you to select the type of objects to evaluate during the analysis. If the components have faceted bodies and the Facet Based setting is used, the reference set of the components need to change to display the faceted bodies. Likewise, if the setting is changed to Use Solids, the reference sets of the components need to be changed to display the solid bodies.

When set to Facet Based Analysis looks for a Facet Representation in each component. If it finds none, Analysis will create them.

When set to Use Solids Where Available Analysis will look for a solid body in each component.

Using Solids is the slowest, but most accurate. I recommend this for the final analysis.

Advanced Clearance Properties

The advanced tab gives you options to speed up your Analysis by specifying components to be ignored as well as setting clearance zones on components to give you a more intelligent analysis.

Pair Zones

Assign to Pairs Allows you to assign a different clearance zone for specific component pairs. When you select Assign to Pairs, the Class Selection dialog displays prompting the you to select the component pairs to assign this clearance zone to. For example, if most of the components in the assembly have a minimum clearance zone of 0.0254 but there are a couple of components that are designed face-to-face, Assign to Pairs allows you to assign a 0.0 clearance zone for only those components. The analysis will apply the 0.0254 clearance zone on the remaining components.

Reset Pair Zones Removes an assigned zones from a component pair. Once a defined zone is removed, the objects reverts to the clearance zone value that was defined for the clearance set.

List Pair Zones This button prompts you to pick a pair of objects to display the clearance zones attached to them.

Object Zones

This allows you to define a clearance zone to one or more selected components. The options on this dialog are identical to those on the Pair Clearance Zones dialog except it is for individual components.

Additional Pairs:

Allows you to select additional pairs of objects to analyze using the Class Selection menu.

Ignored Pairs

Allows you to select pairs of objects to exclude from future analysis runs using the Class Selection menu.

Explicitly Ignored

This option provides a variety of methods to ignore objects during the analysis. If the assembly is particularly large, this can speed up the analysis.

Mated Pairs: Ignores all pairs of components that have been mated.

Pairs Within the Same Subassembly: Ignores all pairs of components that are part of the same Subassembly.

Pairs Within the Same Group: Ignores all pairs of components that are part of group defined under Format Group.

Pairs Within the Same Part: Ignores all pairs of components that are part of the same file.

Clear Results

This option deletes the results from the analysis and marks the clearance set as out-of-date.

Save Interference Solids

This option after the Analysis is ran, creates solid bodies that show all hard or containment interferences. These solid bodies are created as unparameterized features and must not be saved in the assembly file. The default is set to OFF. If this option is toggled on, place the solids on a layer that only contains these solids and that has a user defined name starting with an underscore.

Layer Allows you to specify a layer on which to place the interference solids if the option Save Interference Solids is toggled on.

Interference Color This option allows you to control the color of the created interference solids.

Analysis ReportsAfter performing an analysis, there are two options for displaying the results

and two options for saving the results. Summary Displays an overview of the number of objects analyzed and the number of interferences.Report Displays an information window with a summary, along with the details of the interferences found. Save Report A copy of the report can be saved outside of NX2 using the Save Report command.Save Bookmark This is the same as selecting File | Save Bookmark. It saves the current session in its current state.Store Component Visibility Saves components' current blank and shade status.Restore Component Visibility Returns the component to its original stored visibility.

Clearance Browser

The Clearance Browser provides an easy access to the tools required to perform Assembly Clearance operations. Including creating and managing clearance sets and evaluating clearance analysis results.

If there are no existing clearance sets the browser will be empty otherwise the browser will display the current clearance set.

Interferences: Contains the components that the system found when running the analysis check.Ignored: This folder contains the items you determined to be ignored in the analysis. After an analysis is run, you can drag items from the Interference Folder to the Ignored Folder for avoidance in future runs.Analysis Exceptions: This folder only gets created when there is a problem during the Analysis run.List One: When a one list check is used this folder will contain the components being checked against each other.List Two: When a two list check is used this folder will contain the components being checked against the components in List 2.Additional Pairs to Check: The component pairs in this list are ones the program would normally exclude due to the options checked by you under the Advanced Tab.

Folders in the Clearance Browser The folders contain the information generated from the Analysis and are displayed in the Selected Component column.

Selected Component- Part Number of component checked

Interfering Component- Which component interferes with the selected component

Type- What type of interference was found

Distance- The minimum distance of the Soft Interference found. 0.0000 will be displayed for other Interferences found.

Clearance- The clearance zone initially determined by the user.

Identifier- A unique number is assigned to each interference for your reference.

Out of Date- I a component previously checked has been modified a icon will be displayed.

Unloaded Objects- A icon lets you know if a component has not been loaded.

Text- This column displays any notes that have been added.

Several columns are displayed in the Clearance Browser, communicating all the information regarding a clearance analysis. The Clearance Browser can be sorted in either ascending or descending order by clicking on a column title.

Right-clicking over a Interference will bring up this Sub-Menu to enable you to browse and rapidly evaluate interferences.

Right-clicking over the Clearance Set node in the Clearance Browser displays a pop-up menu that provides quick access to pertinent commands from the submenu.

Sub-Menu of Interferences

Study Interference: Blanks all components except components in interference

Restore Component Visibility: Unblanks all components from previous state.

Redraw interference: Redisplays interference after a view refresh is done.

Reanalyze: Rechecks component pair if changes have been made.

Do Solid Check: Performs most accurate method of analysis when facets were used prior.

Create Interference Geometry: Creates a unparametized solid representing the interference.

Blank Left: Blanks component on the left hand side of component pair list.

Wireframe Left: Toggles off shading of component on left hand side of component pair list.

Flip Shading: Reverses the shading within the component pair.

Reset Shading: Turns off shading on both parts in the component pair.

In this exercise we’re going to check a couple of things. Overlap between the Inner and Outer Door Panel and the Reinforcements to each other.

Load the file ahd84535/001 in TcAE Pontiac database. Check to see if the Reference Sets displayed are REP. If not, you can change this easily and quickly under Assemblies>Components>Replace Reference Sets.Create a Clearance set called "Panel1". Using 2 lists put the PANEL-RR S/D OUTER-RH (15752589) and REINFORCEMENT-ASM RR S/D INR PNL (15752594) on list 1 using the Class Selection method. Put all others on list 2 using the All But Selected method selecting the two parts we just put on list 1.As the designer, you want 1mm overlap interference between the PANEL-RR S/D OUTER-RH (15752589) and the PANEL-RR S/D INR RH (15752593).   Also, you want to know if (15151047) and (15151048) come within 15mm of (15752594). You’ll need to create two Pair Zones for those checks.Save your interferences on layer 252. Use Facet Based mode to calculate your clearances. Analyze your clearances and add text to any interference by typing in the text column of the Clearance Browser.

Click Here to see a snapshot of the resultsNow copy the Clearance Set) Panel1 to Panel2 and repeat the above procedure, but change the Mode to Solid and the layer for interferences to 253.

Click Here to see a snapshot of the results.1. Did you end up with the same results? 2. What were the time differences? 3. Analyze your interferences. How many and what types of objects are they?4. Are there any attributes attached to the objects?

Clearance Analysis Exercise

Analysis Results using Facet Based

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Analysis Results using Solid Based

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