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This task shows how to create a multi-sections
solid.
You can generate it by sweeping one or more planar section curves along
a computed or user-defined spine. The feature can be made to respect one or
more guide curves. The resulting feature is a closed volume. |
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Open the
Multi-sections.CATPart
document. |
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Click Multi-sections Solid
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The Multi-sections Solid Definition dialog box appears.
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Select the three section curves as shown:
They are highlighted in the geometry area.
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The Multi-sections Solid capability
assumes that the section curves to be used do not intersect. |
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Click Preview to get an idea of the feature to
be created.
You can note that by default, tangency discontinuity points are coupled:
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Smooth Parameters
In the Smooth parameters section, you can
check the following options:
- Angular Correction: smoothes 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: smoothes the lofting motion by deviating
from the guide curves.
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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.
Spine
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:
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.
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In case you do not have a GS1 nor GSD license
but a WS1 license, you can select two sections only and you are not allowed
to perform manual couplings. |
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Guides
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For the purpose of our scenario, you are going to use
guide curves. Click the Guide field and select the four joins.
The curves to be used must be joined.
They are highlighted in the geometry area.
It is possible to edit the multi-sections solid reference elements by
first selecting a curve in the dialog box list then choosing a button to
either:
- Remove the selected curve
- Replace the selected curve by another curve.
- Add another curve.
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By default, the application 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 field and select the
spine of your choice in the geometry.
Relimitation
The Relimitation tab lets you specify the
feature relimitation type.
You can choose to limit the multi-sections solid only on
the start section, only on the end section, on both, or on none.
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if the spine is a user spine, the multi-sections
solid is limited by the spine extremities or by the first
guide extremity met along that spine.
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if the spine is an automatically computed spine,
and no guide is selected: the feature is limited by the start and
end sections
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if the spine is an automatically computed spine,
and guides are selected, the feature is limited by the guides
extremities
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Click OK to create the volume.
The feature (identified as Multi-sections Solid.xxx) is added to the
specification tree.
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