Measuring Distances between Geometrical Entities

  This section show you how to measure distances between Geometrical Entities using the Measure Between command .
The following topics are covered:
 
 

Measuring Minimum Distance and Angles
This task explains how to measure minimum and, if applicable, angles between geometrical entities (points, surfaces, edges, vertices and entire products).
Insert the following sample model files: ATOMIZER.model, BODY1.model, BODY2.model, LOCK.model, NOZZLE1.model, NOZZLE2.model, REGULATION_COMMAND.model, REGULATOR.model, TRIGGER.model and VALVE.model. They are to be found in the online documentation file tree in the common functionalities sample folder cfysm/samples.

  1. Click Measure Between . In DMU, you can also select Analyze > Measure Between from the menu bar.
    The Measure Between dialog box appears:

    By default:

    • minimum distances and if applicable, angles are measured.

    • measures made on active products are done with respect to the product axis system.

    • Measures made on active parts are done with respect to the part axis system. 

    Note: This last distinction is not valid for measures made before Version 5 Release 8 Service Pack 1 where all measures are made with respect to the absolute axis system. 

  2. Select the desired measure type.

    Notice that the image in the dialog box changes depending on the measure type selected.

  3. Set the desired calculation mode in the Calculation mode drop-down list box.

  4. Click to select a surface, edge or vertex, or an entire product (selection 1).

    Notes:

    • The appearance of the cursor has changed to assist you.

    • Dynamic highlighting of geometrical entities helps you locate items to click on.

  5. Click to select another surface, edge or vertex, or an entire product (selection 2). A line representing the minimum distance vector is drawn between the selected items in the geometry area. Appropriate distance values are displayed in the dialog box. 
    Notes:
    • For reasons of legibility, angles between lines and/or curves of less than 0.02 radians (1.146 degrees) are not displayed in the geometry area.
    • By default, the overall minimum distance and angle, if any, between the selected items are given in the Measure Between dialog box.
    • For more detailed information about the dialog box options, refer to More About the Measure Between Dialog Box

    Accessing other measure commands

    • Measure Item is accessible from the Measure Between dialog box.

    • In DMU, the Measure Thickness command is also accessible from the Measure Between dialog box. For more information, see the DMU Space Analysis User's Guide.

  6. Select another selection and, if desired, selection mode.

  7. Set the Measure type to Fan to fix the first selection so that you can always measure from this item.

  8. Select the second item

  9. Select another item.

  10. Click Ok when done.
 

Measuring Maximum Distance
This task explains how to measure maximum distance between two G-1 surfaces, two volumes or a surface and a volume.

  1. Click Measure Between . In DMU, you can also select Analyze > Measure Between from the menu bar.
    The Measure Between dialog box appears.

  2. Click Customize... and select Maximum Distance check box in the Measure Between Customization dialog box.

  3. Click OK.

  4. The measure Between dialog box is updated accordingly:

  5. Make your measure:

    • Select the desired measure type (for example Between)

    • Set the desired selection modes (for example Surface only for both selections)

    • Set the desired calculation mode (for example Approximate)

    • Click to select two surfaces, two volumes or a surface and a volume.

    (For example two surfaces Surface in Body 1.1 and Surface in Body 2.1)

  6. Click Ok when done.

Distance is measured normal to the selection and is always approximate. Two options are available:
 

  • Maximum distance from 1 to 2  giving the maximum distance of all distances measured from selection 1.
    Note: This distance is, in general, not symmetrical.

  • Maximum distance giving the highest maximum distance between the maximum distance measured from selection 1 and the maximum distance measured from selection 2.
    Note: All selection 1 (or 2) normals intersecting selection 1 (or 2) are ignored.

Between two G-1 continuous surfaces on a part in Design mode (result is exact)

You can calculate the maximum distance between two G1 (continuous at the tangency level) surfaces (planar or not). The resulting measure is exact.

Notes:

  • G-1 stands for geometric tangency, it basically means: surfaces which are continuous at the tangency level.

  • You can measure maximum distance only with exact geometries (i.e. in Design Mode).

Between Wireframe entities

You can calculate the maximum perpendicular deviation between point, lineic and surfacic elements (except surface/surface which uses max perpendicular distance see table below)

The table below lists the possible wire frame selections for measuring maximum distance:

Entity
Surface
Curve
Point
Surface

 No

 Yes

 Yes
Curve

Yes

 Yes Yes
Point
 Yes Yes MIN

Maximum Perpendicular Deviation Behavior:
 

  • The second element is discretized (with a tessellation independent from the visualization sag)
  • A minimal distance is then, measured between each point of discretization and the first selected element
  • Are kept: only the minimal distances which project orthogonally.

The final value given is the maximum distance value of all kept minimal orthogonal distances.

Consequences:
 
  • The behavior is not symmetric when "Maximum Distance from 1 to 2" is used (except for point selection)
  • The result is approximate
  • If the minimal distance measured between a point of selection 2 and selection 1 is not orthogonal, it is not taken into account. In other words, cases in which there is no orthogonality between the direction given by the two points of the minimal distance and selection 1 are excluded.
  • Required orthogonality to keep the minimal distance within the result is not modeler-tolerant (Logical G1 continuity is not taken into account)
  • Some scenarios do not provide any solution (see example below)

In this scenario, the left part does not return any solution since minimum distances in this zone are obtained at the curve left extremity point and are not orthogonal to the curve.

Measuring Distances in a Local Axis System

The Other Axis option in the dialog box lets you measure distance in a local axis system.

This type of measure is associative: if you move the axis system, the measure is impacted and can be updated.

You need a V5 axis system to carry out this scenario

 

 

  1. Select the Other Axis check box in the dialog box.

  2. Select a V5 axis system in the specification tree or geometry area.

  3. Make your measure.

    In the examples below, the measure is a minimum distance measure and the coordinates of the two points between which the distance is measured are shown.

    Same measure made with respect to absolute axis system:

    Note: All subsequent measures are made with respect to the selected axis system.

  4. To change the axis system, click the Other Axis field and select another axis system.

  5. To return to the absolute axis system, click to clear the Other Axis check box

  6. Click OK when done.