HD64152: ASD: CLASH- THE CLASH VALUE IS NOT EQUAL TO THE MEASURE VALUE O F THE PENETRATION.

APAR status

• Closed as user error.

Error description

• ASD: CLASH- THE CLASH VALUE IS NOT EQUAL TO
  THE MEASURE VALUE OF THE PENETRATION.
  .
  SCENARIO.
  1. Start CATIA V5R16SP07. Work Bench- Assembly
  Design.
  2. Open the Product1.CATProduct .
  3. Click Clash icon, click Apply and then OK.
  4. Observe the value of clash analysis it is -
  4.62mm. This is the problem.
  Error: The clash analysis value is not equal to the
  5mm i.e. the measure value of the penetration.
  .
  .
  EXPECTED RESULT.
  The clash analysis value should be equal to the
  measure value of the penetration.
  .
  .
  

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

• null
  ==========*===========*==========
  Incident Diagnosis.
  The clash analysis value is not equal to the 5mm
  i.e. the measure value of the penetration. This
  behavior is absolutely normal.
  .
  Correction Application.
  There is a difference between the measure and the
  clash computation that is one is based on geometry
  whereas the other is based on tessellation. Further
  it is understood from the documentation that clash
  computation is approximate, and the accuracy
  depends on SAG value. For computing the clash,
  tessellation method is used. Tessellation is cutting
  the surface into number of smaller polygons. Since
  the minimal polygon is a triangle, hence the
  triangle is used for tessellation.
  The minimal size of triangle so as to span the
  entire surface is defined by the SAG value, the
  value which is entered through the UI. The larger
  the sag values the less number of computations,
  but less accurate is the result. The smaller the sag
  value the more is the number of computations and
  more accurate is the result. Hence clash
  computation is always an approximate clash value.
  The clash value is actually the magnitude of the
  penetration vector. A penetration vector is the
  vector which visualizes the depth of the penetration
  i.e. if the body which is in clash if moved in the
  direction of the penetration vector by the
  magnitude of the penetration vector would be out
  of clash (would be just in contact).
  The body if moved by 4.617mm in the direction of
  penetration vector would be in contact would lead
  us to 0.383mm away from the exact positions of
  the bodies.
  Since, the sag of both bodies is set to 0.2mm in the
  default case; they would be in contact,
  if the minimum distance between them is less than
  0.4mm.
  Hence the behavior mentioned in the scenario is
  normal. The user can reduce the SAG value to
  0.01mm, so that he can get the penetration depth
  up to 4.98mm which is very close to 5mm.
  .
  Documentation Reference.
  DMU Space Analysis -> Glossary->SAG
  .
  

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