2011

Active - a clash found in a previous run of the test and not resolved.
Reviewed - a clash previously found and marked by somebody as reviewed.
Approved - a clash previously found and approved by someone.
Resolved - a clash found in a previous run of the test and not in the current run of the test. It is therefore
assumed to be resolved.
Old - any clash in an “old” test. The icons still have the code of the status from the previous run, but this is a
reminder to say that the current test is old. See
clash test status for a description of old tests.
If the status is changed to Approved, Clash Detective takes the user currently logged on as the person who
approved it.
Enabling hyperlinks will show clash results using the relevant status icon
.
clash test status A clash test can have one of 4 statuses:
New indicates a clash test that has not yet been run with the current model.
Done indicates a clash test that has been successfully run with the latest version of the model.
Old indicates a clash test that has been altered in some way since being set up. This might include changing an
option, or having loaded the latest revision of the model.
Partial indicates a clash test that has been interrupted during execution. Results are available up to the point of
interruption.
clearance clash A clash in which the geometry of item 1 may or may not intersect that of item 2, but comes
within a distance of less than the set
tolerance.
duplicate clash A clash in which the geometry of item 1 is the same as that of item 2, located within a distance
of between zero and the set tolerance. A tolerance of zero would therefore only detect duplicate geometry in
exactly the same location.
hard clash A clash in which the geometry of item 1 intersects that of item 2 by a distance of more than the set
tolerance.
intersection method A standard Hard clash test type applies a Normal Intersection Method, which sets the clash
test to check for intersections between any of the triangles defining the two items being tested (remember all
Autodesk Navisworks geometry is composed of triangles). This may miss clashes between items where none of
the triangles intersect. For example, two pipes that are exactly parallel and overlap each other slightly at their
ends. The pipes intersect, yet none of the triangles that define their geometry do and so this clash would be
missed using the standard Hard clash test type. However, choosing Hard (Conservative) reports all pairs of items,
which might clash. This may give false positives in the results, but it is a more thorough and safer clash detection
method.
severity For hard clashes, the severity of a clash depends on the intersection of the two items intersecting. Hard
clashes are recorded as a negative distance. The more negative the distance, the more severe the clash. Hard clash
severity depends on whether the Conservative or Normal Intersection Method has been applied (see
intersection
method
for more details on this). If Normal, the greatest penetration between a pair of triangles is measured. If
Conservative, the greatest penetration of space around one item into the space around another is measured.
For clearance clashes, the severity depends on how close one item invades the distance required around the
second. For example, an item coming within 3mm is more severe than an item coming within 5mm of the other.
For duplicate clashes, the severity depends on how close one item is to the other. When the distance between
them is zero, it is more likely that this is duplicate geometry, where as items that are further apart are more likely
to be different objects and therefore have a lesser severity.
tolerance Tolerance controls the severity of the clashes reported and the ability to filter out negligible clashes,
which can be assumed to be worked around on site. Tolerance is used for
hard clash, clearance clash and duplicate
clash
types of clash test. Any clash found that is within this tolerance will be reported, whereas clashes outside
of this tolerance will be ignored. So for Hard clashes, a clash with a
severity of between zero and the tolerance
value will be ignored, whereas for Clearance clashes, a clash with a severity of more than the tolerance value
will be ignored as it is further away than the distance required. Similarly, a Duplicate clash with a severity of
more than the tolerance value will be ignored as it is likely to be a separate, yet identical piece of geometry.
516 | Glossary