More Geometry Techniques

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More Geometry Techniques

• Healing Virtual GeometryFeature Removal

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The ACIS Healing Husk

• Translating geometry into the ACIS format can be
  often problematic
• Pro/E is less accurate than ACIS if you use the
  default tolerances
• Gaps, overlaps, and internal inconsistencies are
  common
• The ACIS Healing Husk may fix many problems

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Healing in CUBIT

• Healing is accessed from the GeometryVolumeModif
  y panel

Select Heal from the menu
Analyze checks for problems
AutoHeal attempts to fix problems
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What to Try if Healing Fails

• Increase Pro/E accuracy
• Increase both relative and absolute accuracy,
  then re-export the geometry
• Enable Healing Options
• Use the Rebuild option
• Use the Make Tolerant option
• Leave it as it is
• Try meshing. It may be OK with bad geometry
• Try webcutting, imprinting, or merging. If these
  work, the geometry is probably good enough.

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What to Try if Healing Fails
Create Surface from Curves Remove the surface
using the no extend option in the bad area,
construct new surfaces from existing curves and
combine and heal. Use IGES Export the geometry to
IGES, import the IGES file, look for double
surfaces, or surfaces that show up at odd angles
(usually in the same area as the bad geometry).
Delete these surfaces, recreate surfaces if
necessary, and combine. Use Step Export to Step
as a solid model.
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Virtual Geometry

• Changes how algorithms see the geometry without
  changing the underlying solid model
• Partition - Splits 1 entity into multiple
• Composite - Combines multiple entities into 1

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Composite Surface Example
Portion of Wheel Rim, Decatur
Original 32 Surfaces Size 4 Scheme Auto
Composite Surface Size 8 Scheme Map (smoothed)
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Virtual Geometry

• Because ACIS doesnt see virtual geometry
• VG is NOT saved by default with the SAT file
• Can be changed by set attribute on
• VG is saved in .cub file
• Should be done AFTER other geometry operations

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Creating a Composite Surface
Goto GeometrySurfaceModify
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2
Select Composite
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3
1
Select Surfaces
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Click Apply
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Geometry Tweaking

• Surfaces can be moved or replaced
• Adjacent geometry is modified as needed
• Useful for
• Fixing problems such as gaps
• Feature removal

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Replace Surface
Go to GeometrySurfaceModify
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3
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5
Select Tweak
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3
1
Pick Surfaces to remove
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4
Select Replace With Surface
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Exercise 13 - Knuckle

• Steps
• Import knuckle.sat
• Heal the model
• Remove details around holes
• Webcut, where necessary
• Imprint and Merge
• Mesh with a size of 1.5