Spine
By default, the app computes a spine, but if you wish to
impose a curve as the spine to be used, you just need to click the
Spine tab then the Spine box and select the spine of your choice in
the geometry.
In the Spine tab page, you can select the
Spine check box to use a spine that is automatically
computed or select a curve to impose that curve as the spine.
Note that:
- It is strongly recommended that the spine curve be normal to
each section plane and must be continuous in tangency. Otherwise,
it may lead to an unpredictable shape.
- If the plane normal to the spine intersects one of the guide
curves at different points, it is advised to use the closest point
to the spine point for coupling.
- If the spine is automatically computed spine and one or two
guide curves are selected: the multi-sections solid is limited by
the guide extremities. If there are more than two guide curves, the
spine stops at a point corresponding to the barycenter of the guide
extremities. In any case the tangent to the spine extremity is the
mean tangent to the guide extremities.
Coupling
Several coupling types are available in the Coupling
tab:
- Ratio: the curves are coupled according to the
curvilinear abscissa ratio.
- Tangency: the curves are coupled according to their
tangency discontinuity points. If they do not have the same number
of points, they cannot be coupled using this option.
- Tangency then curvature: the curves are coupled
according to their curvature discontinuity points. If they do not
have the same number of points, they cannot be coupled using this
option.
- Vertices: the curves are coupled according to their
vertices. If they do not have the same number of vertices, they
cannot be coupled using this option.
Relimitation
The Relimitation tab lets you specify the removed
multi-sections solid relimitation type.
You can choose to limit the feature only on the Start
section, only on the End section, on both, or on
none.
- when one or both are checked: the feature is limited to
corresponding section
- when one or both are when unchecked: the feature is swept along
the spine:
- if the spine is a user spine, the feature is limited by the
spine extremities
- if the spine is an automatically computed spine, and no guide is
selected: the feature is limited by the start and end sections
- if the spine is an automatically computed spine, and guides are
selected, the feature is limited by the guides extremities.
Smooth Parameters
In the Smooth parameters section, you can check:
- Angular Correction: smooths the lofting motion along
the reference guide curves. This may be necessary when small
discontinuities are detected with regards to the spine tangency or
the reference guide curves' normal. The smoothing is done for any
discontinuity which angular deviation is smaller than 0.5 degree,
and therefore helps generating better quality for the resulting
multi-sections solid.
- Deviation: smooths the lofting motion by deviating
from the guide curves.
If you are using both Angular Correction and
Deviation parameters, it is not guaranteed that the
spine plane be kept within the given tolerance area. The spine may
first be approximated within this deviation tolerance, then each
moving plane may rotate within the angular correction
tolerance.