On user-defined features Christoph M Hoffmann and Robert Joan-Arinyo

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On user-defined featuresChristoph M Hoffmann and
Robert Joan-Arinyo

• ??d??a? F?t???

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?a?aµet???? CAD S?st?µata

• ???a? s?st?µata sta ?p??a t? s??µa ste?e??
  a?t??e?µ???? e?f???eta? ap? ??a s????? pa?aµ?t???
  ?a? pe?????sµ?? ?a? t? a?t??e?µe?? µp??e? ?a
  t??p?p????e? ?? p??? ??p??e? pa?aµ?t???? e??
  ???e? pa?aµ????? sta?e???

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Feature based CAD s?st?µata

• ??a ?a?a?t???st??? (feature) e??a? ??a ?e????
  s??µa t? ?p??? µp??e? ?a s?s?et?ste? µe ???sµ??e?
  ?d??t?te?, ???sµ??a ?????sµata ?a? µe ??p??a
  ???s?. ?? s??µa p??pe? ?a a?apa??st?ta?
  pa?aµet???? ?a? p??pe? ?a ?a???????ta? ?a???e?
  ??a t?? s?µpe??f??? ?a? t?? ?d??t?te? t??
  s??µat??

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S??????a CAD s?st?µata

• ?a s??????a s?st?µata s?ed?as?? e??a? s??????
  ??a? s??d?asµ?? ap? pa?aµet???? ?a? feature-based
  s?ed?as? d??t?

• ??a a?t??e?µe?? ?atas?e???eta? ???s?µ?p????ta?
  ???a p???a????sµ??a a?t??e?µe?a (features)
• ?a a?t??e?µe?a ?atas?e?????ta? ap? ta features µe
  Constructive Solid Geometry (CSG)
• ? a?apa??stas? t?? a?t??e?µ???? ???eta? µe
  pa?aµet????? e??s?se??

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S??????a CAD s?st?µata

• ?a ?a?a?t???st??? a?t? e??a? epa??? ??a t?
  d?µ??????a p???p????? s??µ?t?? a??? ?at? t?
  s?ed?asµ? µ??a????? µe??? ??????ta? a?epa???.

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??p?? ?a?a?t???st????

• ?a?a??µe?? ?a?a?t???st???
• ???p?p????µe?? ?a?a?t???st???
• Datum ?a?a?t???st???

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?a?a?t???st??? ???sµ??a ap? t? ???st? (UDFS)

• ?? CAD s?st?µa ??e? ?a????sµ??a t?p???
  ?a?a?t???st???.
• ?at? ß?s? ta ?a?a?t???st??? a?t? epa????? a??? se
  ??p??e? efa?µ???? a?t? t? s????? ?a?a?t???st????
  de? e??a? ß????? ?a? p??pe? ?a ?p?st???????? ap?
  ?a?a?t???st??? ???sµ??a ap? t? ???st?.

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???sµ?? ?a? ???s? e??? UDF

• ? ???sµ?? e??? UDF e??a? µ?a d?ad??as?a
  s?ed?asµ?? p?? d?µ?????e? t? p??t?t?p? t??
  ?a?a?t???st????.
• ? ???s? e??? UDF e??a? t? st??µ??t?p? e???
  s???e???µ???? p??t?t?p?? UDF se ??a s?µpa??
  s?ed?asµ? se e??????.

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?pa?t?se?? ??a ta UDF

1. ??a UDF µp??e? ?a ???ste? ???s?µ?p????ta?, t?p???
   ?a?a?t???st??? p?? t? CAD s?st?µa pa???e?, ?a?/?
   ???a p??????µe?a ???sµ??a UDF.
2. ? te????? ???st?? p??pe? ?a µp??e? ?a t?p??et?se?
   ?a? ?a p??sa?at???se? t? UDF st? ??µµ?t? p??
   s?ed???eta? µe t?? ?????a ?e?µet????? ????se??,
   ???s?µ?p????ta? t?p???? d?ad??as?e? e?sa?????.
3. ?a UDF p??pe? ?a pa?????? ?a????sµ?????
   µ??a??sµ??? ??a ?a e??????? t?? e?????t?ta t??
   st??µ??t?p?? ?a? t?? p??s?????s?? t??.
4. ?a UDF p??pe? ?a pa?????? ?p?st????? ??a µ?
   ?e?µet???? ?????sµata ?a? pe?????sµ??? µe
   µetaß????.

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??µ??????a s??µat??

• ? ßas???? µ??a??sµ?? ???sµ?? t?? EREP ??e?
  ????et??e? ??a t?? ???sµ? 3D

• ??a ?a?a?t???st??? UDF ????eta? ??a pa?aµet????,
  ?e?µet???? a?t??e?µe?? ap?te???µe?? ap?

1. ??a s????? ap? pa?a??µe?a ?a?a?t???st???,
   t??p?p????µe?a ?a?a?t???st??? ?a? datum
   ?a?a?t???st???.
2. ??a s????? e?sa??µe?? ap? UDF
3. ??a s????? pe?????sµ??.
4. ??a s????? ?????sµ?t??.
5. ???sµ? e??? interface

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??p???????? ???sµ?? ?a?a?t???st????

• ?a t?p??????? ?????sµata e??a? e???st??? ??at?
  µp????? ?a ?p?st???????? ap? p?????? p????e? CAD
  s?st?µ?t?? ?a? e??a? p??? ???s?µa ??a t?? ???sµ?
  s??????? e?????t?ta? t?? ?a?a?t???st????. ??
  µ??a??sµ?? t?? p????a ?a ?a?est??? st?? a??????e?
  t?sse??? pe??pt?se??
• ??µ??????a p?e????, a?µ??, ????f??
• ??a??af? p?e????, a?µ??, ????f??
• ?p?d?a??es? p?e????, ????f??
• S?????e?s? d?? ????f??, a?µ??, p?e????

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??p??????? ?????sµata

1. ???pe? ?a e??a? st? ???? (MBB)
2. ?e p??pe? ?a e??a? st? ???? (MNB)
3. ?p? ????? a? e??a? st? ???? (CIB)

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?p?st????? t?p???????? ?????sµ?t??

• ?a st???e?a p?? ?p?d?a??????a? ???????µ??? ta
  ?????sµata t?? pat??a st???e???.
• ? s?????e?s? d?? st???e??? s??µat?? µe
  d?af??et??? ?????sµata ????? e??a? ?????.
• ?? pa?ap??? ?a???e? µp????? ?a ?pe??a??f???? µe
  ??t??? ?atas?e?asµ????? ap? t? ???st? ?a???e?.

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Volume based topological attributes

1. ???pe? ?a e??a? void (MBV)
2. ???pe? ?a e??a? ????? (MBM)

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???sµ?? UDF

• ? ???sµ?? e??? UDF ?????eta? se d??
  ?p?d?ad??as?e?. ?ata???? ????eta? ? ?e?µet??a.
  St? s????e?a ??????ta? ta ?????sµata t??
  s?stat???? ?a? ?? e??s?se?? pe?????sµ?? ??a t??
  µetaß??t??.

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???sµ?? ?e?µet??a?

• ?? ???sµ?? t?? UDF ?atas?e?????ta? ??????ta? ???e
  s?stat??? µe se???. ?? p??t? s?stat??? p??
  ????eta? ?a?e?ta? p??ta????? s?stat???. ??
  p??ta????? s?stat??? de ???e? ?aµ?a a?af??? se
  st???e?a ????? s?stat????.
• ?? ? ???sµ?? t?? UDF de ???s?µ?p??e? ??a
  p??????µe?a ???sµ??? UDF t?te p??pe? ?a e??a? ??a
  t?p??? ?a?a?t???st??? p?? pa???eta? ap? t? CAD
  s?st?µa. ?? p??ta????? s?stat??? µp??e? ?a e??a?
  ?a? ??a p??????µe?? ???sµ??? UDF.

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???sµ?? ?e?µet??a?

• ??a ?a?a?t???st??? µp??e? ?a e??a? e?te ap?? e?te
  s???et? ap? s?stat??? ?a?a?t???st???, ?ts? ta UDF
  ????? µ?a f?s??? ?e?a????? d?µ?.
• ??t? ? d?µ? µp??e? ?a e?f?aste? ?????? ?? ??a?
  ??????? ?ate?????µe??? ???f?? ?p?? ???e ??µß??
  e??a? ??a s?stat??? ?a? ?? a?µ?? e??a? ??
  e?a?t?se?? µeta?? t??? p??sa?at???sµ??e? ap? t?
  s?stat??? t? ?p??? ???e? t?? a?af??? p??? t?
  s?stat??? st? ?p??? ???eta? ? a?af???. ??
  p??ta????? s?stat??? e??a? ? ???a t?? ???f??.

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???sµ?? ?????sµ?t??

• ?a ?????sµata µp??e? ?a e??a? t?p???????,
  ?e?t???????, a?t????, ?e?µ???? ?a? ???sµ??a ap?
  t? ???st?.
• ?a t?p??????? ?????sµata ???s?µ?p?????ta? ??a ?a
  ?p?st??????? t?? e?????t?ta ?ta? s?????e???µe ??a
  ?a?a?t???st???.

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???sµ?? pe?????sµ??

• ?????? s?ed?ast???? e?d???? µp????? ?a
  e?f?ast??? ???s?µ?p????ta? pe?????sµ??? p??
  ??????ta? ?? µa??µat???? e??s?se?? µeta??
  µetaß??t?? ap? t?? ?p??e? e?a?t?ta? t? s??d??.
  ?? pe?????sµ?? ??????ta? ?? p????f???e? ?e?µ????.
• ?? pe?????sµ?? e??s?se?? s???p?????? se s??d?asµ?
  µe ?e?µet?????? pe?????sµ???. G?a ?a
  ?p?st???????? t?t???? pe?????sµ??, t? s?st?µa CAD
  p??pe? ?a d?a??te? d?ad??as?e? p?? ?a
  ap?s????t??? t?t??e? e??s?se?? ?a? ?a ?????? t?
  s?st?µa t?? pe?????sµ??.

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S?µp????s?

• ? s?µp????s? apa?te?ta? ?a?? ???sµ???
  ?e?t???????t?ta ?a? ??a ????????µ??? ?a? ?a??
  ???sµ??? interface.
• ? ?e?t???????t?ta e?f???eta? ap? t? ?e?µet??a ta
  ?????sµata ?a? t?? e??s?se??.

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???????µ???t?ta

• ?a UDF ?atas?e?????ta? ap? t?p??? ?a?a?t???st???
  t?? CAD ?a?/? ap? ???a UDF. ?? ??? UDF
  ???????µe? ?????sµata a??? µp??e? ?a ??e? ?a? ??a
  d??? t??.
• ?p??e?t??? ???????µ???t?ta pa???eta? ?? ??a?
  ep?p??s?et?? µ??a??sµ??

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S?????e?s? ?a?a?t???st????

• ? s?????e?s? ?a?a?t???st???? e??a? ? d?ad??as?a
  µe t?? ?p??a ? ???st?? pe???aµß??e? ??a ???
  ?a?a?t???st??? st? µ???? p?? s?ed???eta?. ?
  d?ad??as?a a?t? e??a? d?? ß?µ?t?? ???sµ??
  s?????e?s?? ?a? ap?t?µ?s? t?? s?????e?s??.

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??????t?ta

• ? e?????t?ta t?? UDF d?a?????eta? se d?? ß?µata.
  ?ata???? ?ta? ????eta? t? ?a?a?t???st??? p??pe?
  ?a ?p???e? µ?a p??ta????? e?t?µ?s? a? e??a?
  ??????. St? s????e?a ?ta? t? UDF s?????e?eta? se
  ??p??? µ???? ? se ???? ?a?a?t???st??? p??pe? ?a
  ?p???e? ????? ??e???? e?????t?ta?.

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??????t?ta ?at? t?? ???sµ?

• S??ta?t???? ??e???? t?? pe?????sµ??.
• S???pe?a t?? ???sµ?? t?? ße???e???? t??
  pa?aµ?t???.

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??????t?ta ?at? t? s?????e?s?

• ?ta? ??a UDF s?????e?eta? se ??a µ???? ??p??e?
  ???t??e? p??pe? ?a e??????? t?? e?????t?ta.
• ???? ?? pe?????sµ?? p?? ????? te?e?
  ep?ßeßa?????ta?.

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