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Direction of the tangent vector and normal vector |
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You can set the position of the tangent vector and normal vector as follows.
•Selecting an object to define the direction of the tangent vector/normal vector.
Before selecting an object, please activate the corresponding field on the Parameter Panel: for the tangent vector – the Tangent Direction field, for normal vector – the Direction of the normal field. You can use any point, rectilinear or straight-line object as a guiding object. Details...
•Rotation of the tangent vector/normal vector using the defining points of the phantom in the graphic area. Details...
•Constructing a vector is performed during the process of creating a spline using the Build Vector 
button located next to the Tangent Direction field (for the tangent vector) or the Direction of the normal field (for the normal vector). More details about vector construction...
If an object was selected or a vector was plotted to set the direction of the tangent/normal vector, then its name will be displayed n the Tangent Direction or Direction of the normal field, respectively. The position of the tangent vector/normal vector is fixed.
Selection of the guiding object
You can use any of the following as a guiding object to plot a tangent vector or a normal vector:
•point object – the direction is determined by the straight line passing through the point object and the spline point used to manage the shape,
•straight-line object – the direction is defined by the straight line that is parallel or perpendicular to this object. You can select the required option using the Orientation group of buttons (
and 
), which appears on the Parameters Panel after specifying the object.
•planar object – the direction is determined by the straight line that is perpendicular to this object.
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If the direction of one vector is set by a guiding object then the guiding object of the second vector has to be perpendicular to the first vector. |
Rotation of the tangent vector and normal vector
You can rotate the tangent vector or the normal vector around any of the two basis vectors. You can also arbitrarily rotate the tangent vector/normal vector.
For arbitrary rotation, use the Swivel point at the end of the phantom of the corresponding vector.
Rotation around basis vectors is performed using the following points:
•Around tangent vector – normal vector is rotating,
•Around normal vector – tangent vector is rotating,
•Around binormal vector – tangent vector and normal vector are rotating.
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If curvature parameters are not set, i.e., the Curvature Control switch is in the 0 (off) position, then the normal vector phantom and the Around tangent vector point are not displayed in the graphic area. |
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If the direction of one vector is set by a guiding object then the second vector can only be rotated around it. Rotation around a binormal vector is not possible. |
Rotate the vectors as required. The spline phantom will be rebuilt.
See Also
