1. Measure Features, Feature Relations and Datum Analysis Features
Ron Thellen
Johns Hopkins University Applied Physics Laboratory

2. APL … At a Glance
University-Based Applied Research & Development Laboratory
Focus on National Security
Major efforts in Space Science & Technology
Partner in Johns Hopkins Commitment to Education & Medicine
4000 Employees

3. APL … Recent Space Science Examples
New Horizons
10 Year, 3 Billion Mile Journey to Pluto and beyond
STEREO
Twin satellites capturing stereo images of the sun
MESSENGER
1st spacecraft to orbit Mercury

4. Topics of Discussion Measure Features
Distance
Angle
Area
Feature Relations and Feature Parameters
UDA (User Defined Analysis)
Construction Groups
Field Datum Points
Sensitivity Studies

5. Review Two Case Studies
Surface Area Analysis
Measure Features
Feature Relations/Parameters
Sensitivity Analysis
Field of View Study
UDAs
Field Datum Points
Construction Groups

6. Surface Area Analysis Problem
Analyze the change in area of multiple surfaces as the shape of the model changes.
Graphically capture the resulting changes to the model.
Pass the results to Excel for further study.

7. Surface Area Analysis Initial Conditions
Given a column of material containing spherical cavities
Monitor surface area of
Flat green surface
Red spherical cavity
Blue spherical cavity
Additional cavities…

8. Surface Area Analysis Further Conditions As column height decreases
Green plane contacts red sphere
At that point the red sphere begins increasing in size
Eventually the red sphere contacts the blue sphere
At that point the blue sphere begins increasing in size

9. Surface Area Analysis Start the Model DTM1 is offset from TOP
DTM2 is offset from DTM1
Extrude 1 is sketched on TOP and extruded to DTM2

10. Surface Area Analysis Build 1st Sphere
Sketch Datum Curve for initial sphere size
Create CS0 at top of curve
Used to measure flat green surface location relative to initial sphere size and location
Create Distance Measure Feature
Create spherical cut
Do not use sketched datum curve above
Group features

11. Surface Area Analysis Build Additional Spheres
Repeat steps in previous slide
For each sphere’s Distance Measure Feature
Measure from its grouped CSYS to the sphere above

12. Surface Area Analysis Create Area Measures
Create Area Measure Features for
Flat green plane
Red sphere
Blue sphere
Yellow sphere
Create Annotation to display measure results

13. Measure Features An Overview Analysis  Measure … Common to all…
Distance
Angle
Area
Common to all…
Select features to measure
Select type of measure (Quick, Saved or Feature)
Assign name (for Saved and Feature)
For Feature types
Regenerate status and optional Feature Parameters and Datum Features

14. Measure Features Distance Example Select measure entities
From – To
Returns distance
Select optional projection reference
Returns dx, dy, dz in addition to distance
Change type from Quick to Feature
Assign appropriate name

15. Measure Features Distance Example (cont.) Select Feature tab
Select Regenerate type
Always, Read Only, Design Study
Select optional feature parameters to create
DISTANCE_Y is of interest in this case
Select optional datum features to create

16. Feature Relations and Parameters
Tools  Relations (includes parameters) or…
Tools  Parameters
Relations and Parameters can apply to
Part (default)
Feature
Other…

17. Feature Parameters Change “Look In” from Part to Feature
Select the Feature in
Model Tree or…
In model
Select Add Parameter
Assign Name and Value to the Parameter
This is only an example. It is not used in this study.
As shown earlier, Feature Parameters can also be created as part of a Measure Feature

18. Feature Relations Change “Look In” from Part to Feature
Select the Feature in
Model Tree or…
In model
Enter relation
This Feature Relation is what causes the sphere radius to increase
Create an equivalent relation for each sphere

19. Relation in Detail What does it say? distance_y FID_
is the Feature Parameter created while defining the Measure Feature
FID_
Feature ID
DTM2_TO_CS0_DISTANCE
The name of the Measure Feature

20. Relation in Detail But what does it say?
If the feature parameter named “distance_y”, in the (:) feature with the id (FID_) named “DTM2_TO_CS0_DISTANCE” is less than (<) 0
Dimension d14 is assigned the value of the Part parameter named “pore_start_radius” minus the value of the feature parameter named…

21. Feature Relations Shortcut
In the Relations editor enter the starting text
Press the Insert Parameter Name from List button

22. Feature Relations Shortcut (cont.)
In the Relations editor enter the starting text
Press the Insert Parameter Name from List button
In the Select Parameter dialog, change to Feature and select the Measure Feature in the model tree

23. Feature Relations Shortcut (cont.)
In the Relations editor enter the starting text
Press the Insert Parameter Name from List button
In the Select Parameter dialog, change to Feature and select the Measure Feature in the model tree
Select the parameter and press Insert Selected
The feature parameter is added to the relation

24. Surface Area Analysis Back to the Model
We could edit the offset value of DTM2 manually to exercise our model… but where’s the fun in that?

25. Sensitivity Analysis Analysis  Sensitivity Analysis…
Used to examine how sensitive your model is to dimensional changes
Some initial setup options
Preferences
Animate Model (Yes!)
Default range
Set’s the default range for selected dimension you will adjust (I usually skip this and adjust the range manually)

26. Sensitivity Analysis The Dialog Set Options Assign Study Name
Select Variable Dimension
DTM2 offset dim
Set Variable Range
Select Parameter to plot
One of the Area Measure Feature parameters
Set the # of Steps
More steps = finer analysis
Compute

27. Sensitivity Analysis
The Displayed Results

28. Sensitivity Analysis
The Graphed Results
???
SPR

29. Sensitivity Analysis
The Graphed Results (cont.) 2 3 1 2 3 4 1
??? 4

30. Surface Area Analysis Summary Utilized…
Measure Features
Feature Relations/Parameters
Sensitivity Analysis
Analyzed the change in area of multiple surfaces as the shape of the model changed.
Graphically captured the resulting changes to the model.
Passed the results to Excel for further study.

31. Review Two Case Studies
Surface Area Analysis
Measure Features
Feature Relations/Parameters
Sensitivity Analysis
Field of View Study
Construction Groups
Field Datum Points
UDAs

32. Field of View Study Problem
Determine the reduction in a field of view that is caused by an obstruction
Determine % reduction in the field of view

33. Field of View Study
Assumption
Field of View origin is a point

34. Pro/PHOTORENDER Analogy
Field of View origin = Point light source
Obstructed volume = Shadow cast by obstruction

35. Field of View Study Create Field of View Model
Half sphere in this example
Assemble into assembly where we will view the results of the study
Assign appropriate references
Csys to csys in this example (focal point)

36. Field of View Study Create Area Measure Feature
In order to determine % reduction in Field of View
Create an Area Measure before we create features that will cut out the obstructed volume (Analysis  Measure  Area)

37. Field of View Study Create Additional Construction Geometry
Used for subsequent feature creation
Focal Point
Axis of Rotation
Projection Plane (offset from sphere surface)

38. Field of View Study Copy Obstruction Geometry
Insert  Shared Data  Copy Geometry…
Only the surface quilt of one part was selected (in this case)

39. Field of View Study Intersect Copied Geometry Create Datum Plane
Through Axis of Rotation
Offset (at an angle) from existing plane (FRONT)

40. Field of View Study Intersect Copied Geometry (cont.)
Create Datum Plane
Through Axis of Rotation
Offset (at an angle) from existing plane (FRONT)
Intersect Datum Plane with Copied Geometry
Edit  Intersect…

41. Construction Group A Construction Group…
Includes geometry features (usually Datum Features)
Can include a Field Datum Point
Must include an Analysis Feature (and it must be the last feature in a Construction Group, otherwise it is just a Group)
Used by User Defined Analysis (UDA)
If the first feature is a Field Datum Point, the Analysis Feature measure can be solved across the entire length of the curve or over the entire surface it is created on (the domain)

42. Construction Group (cont.)
Do not use the features in a Construction Group for subsequent modeling activities
After creating the Construction Group, suppress it
It will still be selectable for UDA purposes

43. Field Datum Point Insert  Model Datum  Point  Field… or
A Field Datum Point…
Is a dimensionless Datum Point
Exists within the domain of a
Datum Curve
Surface

44. Field of View Study Field Datum Point (for Construction Group)
Create the Field Datum Point on the intersect curve created previously

45. Field of View Study Datum Axis (for Construction Group)
Create a Datum Curve from the Focal Point to the Field Datum Point

46. Field of View Study Measure Angle Feature (for Constr. Group)
Create a Measure Angle Feature to measure the angle between the Axis of Rotation and the Datum Axis just created. Use the Datum Plane previously created as your projection plane.

47. Viewed looking at DTM1 (the projection reference)
Field of View Study
Measure Angle Feature (cont.)
Pay close attention to the blue measure arrows. Use the yellow flip arrows if necessary.
Set Plot range to +/-180
Viewed looking at DTM1 (the projection reference)

48. Field of View Study Measure Angle Feature (cont.)
Create the PROJ_ANGLE parameter
Set Regenerate to Always

49. Field of View Study Create the Construction Group
Select the features to include in the Construction Group
Group the features
Suppress the Group

50. User Defined Analysis (UDA)
A UDA is a specific type of Datum Analysis Feature
Insert  Model Datum  Analysis… or
Used to create measures or analyses beyond those available in the Analysis menu

51. Field of View Study Create the UDA Step through the analysis elements
Name
Type
Regen Request

52. Field of View Study Create the UDA (cont.)
Step through the analysis elements
Name
Type
Regen Request
Definition
Select Type (Construction Group)
Select Parameter and Domain
Compute

53. Field of View Study Create the UDA (cont.)
Step through the analysis elements
Name
Type
Regen Request
Definition

54. Field of View Study Create the UDA (cont.)
Step through the analysis elements
Name
Type
Regen Request
Definition
Result Params

55. Field of View Study Create the UDA (cont.)
Step through the analysis elements
Name
Type
Regen Request
Definition
Result Params
Result Datums

56. UDA Wrap-Up Uses a Construction Group When the UDA regenerates
Field Datum Point
Datum Axis
Angle Measure Feature
When the UDA regenerates
Field Datum Point traverses the Datum Curve (domain) it is placed on from beginning to end
The Angle Measure is calculated at every position of the Field Datum Point
A Datum Point is created at the maximum measured angle

57. Maximum measured angle found!
UDA Wrap-Up (cont.)
Maximum measured angle found!

58. Field of View Study Create Another Datum Axis Through the…
Focal Point
UDA_MAX_PNT
This point goes through the focal point and is tangent to the obstruction geometry surface

59. Field of View Study Create an Intersect Datum Point Using the…
Datum Axis just created
PROJ_PLANE created earlier

60. Progress So Far We have created… Intersect Datum Curve
Field Datum Point on that curve
Axis from the Focal Point to the Field Datum Point
Angle measure from Axis of Rotation to that axis
A UDA with a datum point at the max measured angle
A “tangent” axis through the Focal Point and max point
A datum point on the projection plane by intersecting the tangent axis with the projection plane

61. What’s Next? Repeat the Indicated Geometry Creation
The initial Datum Plane in each group of features will have its angular offset measured from the previous Datum Plane

62. What’s Next? (cont.) How Many Times Do You Repeat?
The purpose of each group is to create two datum points
At the max angle on the obstruction geometry surface
On the projection plane
Each set of points will be used to create
A datum curve on the obstruction geometry
A datum curve on the projection plane (a shadow)
A greater number of points will create more accurate datum curves – you decide!

63. Field of View Study
Result of Repeated Geometry Creation

64. Field of View Study Create Datum Curves Through “max” points
Through projected points

65. Field of View Study Create Boundary Blend
Through projected datum curve
Through “max” curve
Through Focal Point

66. Field of View Study Remove Material from Field of View
Select Boundary Blend
Edit  Solidify

67. Field of View Study Create 2nd Area Measure Feature
In order to determine % reduction in Field of View
Create a 2nd Area Measure after we cut out the obstructed volume (Analysis  Measure  Area)

68. Field of View Study
Create a Part Relation to Calculate the % Reduction in Surface Area

69. Resulting Field of View Geometry

70. Field of View Study Summary Utilized…
Measure Features
Construction Groups
Field Datum Points
UDAs
Determined the reduction in a field of view caused by an obstruction
Determined % reduction in the field of view

71. Questions?