HD24478: SHAPE DESIGN : MAINTAINING HYPERBOLID PARABOLOID SURFACES WHEN THEY GET TOO SKINNY

APAR status

• Closed as Permanent restriction.

Error description

• It is a problem with maintaining hyperbolid
  paraboloid surfaces when they get too 'skinny'.
  Attached is a pdf showing the process and the file
  that the images were generated from.
  .
  Hyperbolic paraboloid surfaces are defined with
  doubly ruled lines from the four edges.
  Interestingly Rhino will still make the surface when
  CATIA will not
  .
  Scenario:
  - Open the provided CATPart file
  - Workbench GSD
  - Double click Point.2
  - Change the Y coordinate to 7 then 6 then 5 then 4
  then 3.
  ==> At (0,5,10), the surface deforms : t is wrong
  .
  .
  

Local fix

Problem summary

• Shape Design : maintaining hyperbolid paraboloid surfaces when
  they get too skinny
  It is a problem with maintaining hyperbolid
  paraboloid surfaces when they get too 'skinny'.
  Attached is a pdf showing the process and the file
  that the images were generated from.
  .
  Hyperbolic paraboloid surfaces are defined with
  doubly ruled lines from the four edges.
  Interestingly Rhino will still make the surface when
  CATIA will not
  .
  Scenario:
  - Open the provided CATPart file
  - Workbench GSD
  - Double click Point.2
  - Change the Y coordinate to 7 then 6 then 5 then 4
  then 3.
  ==> At (0,5,10), the surface deforms : t is wrong
  .
  .
  

Problem conclusion

• THIS PROBLEM IS PERMANENT RESTRICTION IN
  CATIA
  .
  Incident Diagnosis :
  To change the Y Coordinate of Point.2 to 7 when 5
  gives a wrong result with Fill Surface.
  .
  Restriction Explanation
  In this case , the Fill inputs are 4 curves and a
  point.
  From the inputs , Fill algorithm computes an initial
  surface and deforms this surface to satisfy the
  given constraints.
  When Y=5, the initial surface computed is a Plane.
  The projection of the Point on this plane is outside
  the projection of the curves on the plane. This is a
  restriction of fill algorithm and that is why the result
  is bad.
  .
  .
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

Applicable component levels