Click Curve Smooth
.
The Curve Smooth Definition dialog box is displayed.
Select the curve to be smoothed.
Texts are displayed on the curve indicating its
discontinuities before smoothing and the type of discontinuity (point,
curvature or tangency) and their values. These values
are expressed in the following units:
-
for a point discontinuity: the unit is the document's
distance unit (mm by default)
-
for a tangency discontinuity: the unit is the
document's angular unit (degree by default)
-
for a curvature discontinuity: the value is a ratio
between 0 and 1 which is defined as follows:
if ||Rho1-Rho2|| / ||Rho2|| < (1-r)/r where Rho1 is the curvature vector on one side of the
discontinuity, Rho2 the curvature vector on the other side, and
r the ratio specified by the user; then the discontinuity is smoothed.
For example, r=1 corresponds to a continuous curvature and
r=0.98 to the model tolerance (default value). A great
discontinuity will require a low r to be smoothed.
Click Preview to display texts indicating the
curve discontinuities that are still present after the smoothing
operation, and whether they are within the threshold values (yellow flag)
or outside the set values (red flag).
The value and location of
the Maximum deviation between the curve to
be smoothed and the smoothed curve are displayed in the 3D area.
In the example, from top to bottom, once the curve is smoothed:
- the tangency discontinuity is still present
- there is no more discontinuity, the point discontinuity is
corrected
- the curvature discontinuity still is present, even though it is
slightly modified (different In and Out
values)
- the curvature discontinuity still is present and not improved
at all
Basically:
- a red box indicates that the system could not find any solution
to fix the discontinuity while complying with the specified
parameters
- a yellow box indicates that some discontinuity has been
improved, where there was a point discontinuity there now is a
tangency discontinuity for example
- a green box indicates that the discontinuity no longer exists;
it has been smoothed.
Optional: Modify the Tangency threshold, that is the tangency discontinuity value above
which the curve is smoothed. If the curve presents a tangency discontinuity greater than this
threshold, it is not smoothed.
Optional: Select the Curvature threshold check box
to set curvature discontinuity value above which the curve is smoothed.
Optional: Define a Maximum deviation
value to set the allowed deviation between the initial curve and the
smoothed curve. Therefore, the resulting smoothed curve fits into a pipe which radius is
the maximum deviation value and the center curve is defined by the
selected curve.
Optional: Define the Continuity, that is the correction mode for the smoothing, by
checking either:
-
Threshold: default mode. The tangency and curvature
thresholds options are taken into account.
-
Point:
no point discontinuity should remain.
There is no point discontinuity in our example.
-
Tangency: no tangent discontinuity should remain. The
tangency threshold option is not taken into account, it is grayed
out and the defined value is ignored.
-
Curvature: no curvature discontinuity should remain. The
curvature threshold option is not taken into account, it is grayed
out and the defined value is ignored.
You notice that there is no discontinuity any more:
In case tangent or curvature discontinuities remain, an
error message is issued.
-
When a curve is curvature
continuous and you try to smooth it, a warning message
informs you that there is no discontinuity to smooth.
Nevertheless, you can still improve the curve smoothing by
clicking on Preview or OK in the Curve
Smooth Definition dialog box.
-
The following options are
grayed out when smoothing a curve that is curvature
continuous: both Tangency and Curvature Thresholds, all the
Continuity options and the Freeze tab.
Optional: You can select a surface on
which the curve lies. In this case the smoothing is performed so that the curve remains on
the Support surface. This ensues that the maximum
degree of smoothing is limited by the support surface's level of
discontinuity.
Click the Freeze tab.
This tab enables you to select sub-elements of the curve that
should not be smoothed.
These sub-elements can either be vertices or edges. In case of a
vertex, the local neighborhood remains unchanged, thus keeping the
discontinuity.
The Remove button enables to remove a single or a set
of sub-elements.
You now set continuity
conditions on the resulting smoothed curve for each extremity with
regards to the input curve. As a comparison basis, the continuity
condition was previously always curvature: the output curve had the
same extremity points, tangencies and curvatures as the input curve.
Click the Extremities tab and define the
continuity conditions at each curve's extremity:
-
Curvature (by default): extremity point, tangency and
curvature are the same
-
Tangency: extremity point and tangency are the same
(curvature can be different)
-
Point:
extremity points are the same (tangency and curvature can be
different)
You can also right-click the icon at the curve's
extremity and choose one of the following options. You can
sequentially move from one condition to the next one by clicking on
the icons.
Click the Visualization tab.
This tab lets you define the way the messages are displayed on the
smoothed element. You can choose to see:
- All: messages indicating where the discontinuity
remains (red box) as well as those indicating where the
discontinuity type has changed, or allows smoothing.
- Not corrected: only the messages indicating where
the discontinuity is not corrected and remains.
- None of the messages.
You can also choose to:
- Display information interactively:
only the pointers in the geometry are displayed,
above which
the text appears when passing the pointer.
- Display information sequentially:
only one pointer and text are displayed in the geometry, and you
can sequentially move from one pointer to the other using the
previous/next buttons.
The Topology simplification option automatically
deletes vertices on the curves when the curve is curvature continuous
at these vertices, thus reducing its number of segments.
When it is the case, the displayed text indicates:
Out:
vertex erased to inform you that a simplification operation
took place. This text is also displayed when two vertices are very close to each
other and the system erases one to avoid the creation of very small
edges (i.e. shorter than 10 times the model tolerance) between two
close vertices.
Click OK.
The smoothed curve (identified as Curve smooth.xxx)
is added to the specification tree.