Detecting Interferences Using the Clash

• About Detecting Interferences

• DMU P2 Capabilities

• Step-by-Step Scenario

• Defining Interferences Types

• Defining Computation Types

• About Selection

Interference checking and analysis is done on polyhedric models represented by triangular meshes. By default, checking for interferences is done in two steps and is well suited for reviews in which all conflicts do not require analysis every time.

•  Initial computation:  detects and identifies the different types of interference.

• Detailed computation: computes the graphics representation of interferences (triangles for contacts and clearances, curves for clashes) as well as the penetration depth or minimum distance.

By default, penetration depth is calculated at element level. You can change this setting on the DMU Clash - Penetration tab of your settings.

You can change the default settings  (DMU Clash tab) to have:

• The penetration depth and minimum distance calculated for all interferences detected during this step. This will let you sort conflicts in increasing value of penetration depth, for example, and you can then begin your analysis with the most serious conflicts.

• All numeric and graphic results defined in the Detailed Computation tab computed for all interferences detected during this step. This means that the initial computation takes longer, however, access to all results is immediate.

• You can change the detailed computation default settings (DMU Clash - Detailed Computation tab).

• In DMU-P2, you can customize the default type and clearance value settings using the Tools > Options... command (DMU Clash tab under Digital Mockup > DMU Space Analysis).

• Authorized penetration: lets you define a margin within which two products can occupy the same space zone without generating a clash. Sag is taken into account.
  Enter the value in the field that becomes active next to the interference type.
  This is particularly useful when dealing with cables,  joints and other flexible objects, for example.

• Clash rule: lets you use knowledgeware capabilities in the Clash command.

Insert the following sample cgr files: ATOMIZER.cgr, BODY1.cgr, BODY2.cgr, LOCK.cgr, NOZZLE1.cgr, NOZZLE2.cgr, REGULATION_COMMAND.cgr, REGULATOR.cgr, TRIGGER.cgr and VALVE.cgr.

They are to be found in the online documentation filetree in the common functionalities sample folder cfysm/samples.

1. Select Insert > Clash from the menu bar, or click Clash in the DMU Space Analysis toolbar.
   The Check Clash dialog box appears. An entry for the interference appears in the specification tree.

   The default interference analysis is detecting clashes and contacts between all components in the document.

2. Activate the first Type drop-down list box and select the interference type

3. If you set the interference type to Clearance + Contact + Clash, enter the desired clearance value in the field that becomes active next to the interference type.

   Clearance value: The value entered must not be less than twice the sag.

4. Activate the second Type drop-down list box and select the computation type.

5. Select the products to check for interference: If you set the computation type to Between two selections, define the first selection then click to activate the second selection field (Selection 2) and select desired products.

6. Click Apply to check for interferences.

   A progress bar is displayed letting you monitor and, if necessary, interrupt  (Cancel option) the calculation. The Check Clash  dialog box expands to show the results and a Preview window appears showing the products in conflict.
   	Note: If the calculation is canceled, no results are displayed.

7. Simply change the calculation parameters (interference type and selection) and click Apply to run another interference analysis.

Defining Interference Types

• Contact + Clash: checks whether two products occupy the same space zone as well as whether two products are in contact (the minimum distance is less than the total sag).
• Clearance + Contact + Clash: In addition to the above, checks whether two products are separated by less than the pre-defined clearance distance.Results differ depending on the interference type selected for the analysis. See figure.
• Authorized penetration: lets you define a margin within which two products can occupy the same space zone without generating a clash.
  Sag is taken into account.

  Enter the value in the field that becomes active next to the interference type. This is particularly useful when dealing with cables, joints and other flexible objects, for example.
  Note:  Do not combine this interference type with the Retrieve Information from PDM setting (Tools > Options, Digital Mockup > DMU Space Analysis, DMU Clash tab).

• Clash rule: lets you use knowledgeware capabilities in the Clash command.

Defining Computation Types

• Between all components: tests each product in the document against all other products.

• Inside one selection: within any one selection, tests each product of the selection against all other products in the same selection.

• Selection against all: tests each product in the defined selection against all other products in the document.

• Between two selections: tests each product in the first selection against all products in the second selection.

About Selection

• Any sub-assembly in the specification tree is considered a valid selection.

• Continue clicking to select as many products as you want. Products are placed in the active selection. To de-select products, reselect them in the specification tree or in the geometry area.

• Click in selection fields (fields turn black) to view your selections and be certain that you have selected the products you intended: selected products are highlighted.

• It is possible to display and edit clash selection using the Part Selection functionality in a Process document (for more detailed information, refer to  DELMIA - 3D Simulation for Manufacturing User's Guide "