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- Defining size with object axis length as a size reference does not
assist reasoning about object interaction, because it obscures the
relative sizes of shape features on different objects (since shape
features on each object are related to the axis on that object
only). Reference to axis length would be more useful in solving
problems in CAD, object classification, or other areas where objects
are considered one at a time.
- Description of the size of shape features by comparison to the major
axis fails to recognise the common case where two shape features fall
within the same subdivision of the axis size, but have a functionally
important difference between their own sizes.
- Although object axes can provide functional information, local shape
features on the object boundary are far more significant where close
interaction between objects is occurring, and the relative orientation
of features is therefore more important in this situation than axis
orientation is.
- The methods for describing location and orientation of shape features
are rather clumsy. They describe location and orientation sufficient
that object shape can be largely reconstructed (by a human) from the
description, but they are difficult to use when reasoning about motion
is being carried out.
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Up: Axially Specified Subparts and
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Alan Blackwell
2000-11-17