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Action:
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Creates a "rib" curve, running from one base entity to the other, at a location along a blend determined by the v-parameter.
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Filename:
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blnd/blnd_scm/blnd_scm.cxx
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APIs:
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api_make_blend_cross_curve
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Syntax:
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(blend:make-cross-curve edge real [acis-opts])
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Arg Types:
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edge
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edge
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real
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real
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acis-opts
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acis-options
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Returns:
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entity
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Description:
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Gets an edge with an attached blend attribute and the value of a v-parameter along the blend. Given an edge with an attached blend attribute (currently, only ATTRIB_VAR_BLEND or ATTRIB_CONST_ROUND) and a v-parameter along the blend, this extension creates a "rib" curve, running from one base entity to the other, at a location along the blend determined by the v-parameter. (The v-parameter runs along the blend, and the u-parameter runs from one base surface to the other.) The v-parameter of the blend is the same as that of its defining curve, which is generally the curve of the edge being blended.
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Sometimes the blend cannot evaluate a cross curve at the given parameter, for example, if the blend radius is too big.
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The returned entity is a "rib" curve.
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edge is an edge with an attached blend attribute and the value of a v-parameter along the blend.
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real is the v-parameter - value of the parameter along the blend.
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acis-opts contains optional parameters that are specific to the component and general
ACIS options such as the journal and version information. The
option argument (must be the last argument) is a class derived from
acis-opts.
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Limitations:
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Currently, only ATTRIB_VAR_BLEND or ATTRIB_CONST_ROUND
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Example:
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; blend:make-cross-curve
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; Set up views.
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(part:clear)
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;; #t
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(define view (cond ((>= 0 (length (part:views)))
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(define dlv (view:dl 0 0 600 600)))))
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;; view
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(define iso (map iso (env:views)))
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;; iso
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; Define geometry to illustrate command.
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; Define cylinder length H, radius r, wing span
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; S, and surface curvature R.
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(define H 30.0)
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;; H
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(define r 4.0)
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;; r
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(define S 40.0)
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;; S
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(define R 8.0)
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;; R
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; Create a cylinder and then a wing.
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(define cyl (solid:cylinder (position (/ H -2) 0 0)
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(position (/ H 2) 0 0) r))
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;; cyl
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(define wing (solid:cylinder (position 0 0 0)
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(position 0 (- 0 S) 0) R))
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;; wing
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; Create a tool to cut the wing.
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(define tool (solid:block (position (/ S -2) (* -2 S)
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(/ S -2)) (position (/ S 2) (* 2 S) (/ S 2))))
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;; tool
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; Slightly rotate and change the angle of the tool.
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(define transform1 (entity:transform tool
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(transform:rotation (position 0 0 0)
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(gvector 1 0 0) -4)))
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;; transform1
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; Transform the tool.
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(define transform2 (entity:transform tool
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(transform:translation
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(gvector 0 0 (+ (/ S -2) r)))))
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;; transform2
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(define subtract (solid:subtract wing tool))
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;; subtract
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; Round out the wing's leading edge.
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(option:set "raysize" (/ R 4))
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;; 1
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(define lead_edge (pick:edge (ray (position (/ R -2)
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(/ S -2) R) (gvector 0 0 -1))))
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;; lead_edge
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; Attach the variable round blend attributes to edge.
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; Blending preview visible in OpenGL only.
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(define blend1 (blend:var-round lead_edge 1.0 0.25))
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;; blend1
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; Fix the blend network.
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(define blend_fix (blend:fix lead_edge))
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;; blend_fix
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; Move wing into proper place.
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(define move_wing (entity:transform wing
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(transform:translation
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(gvector 0 0 (- (* 0.75 r) R)))))
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;; move_wing
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; Unite the cylinder and the wing.
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(define unite (solid:unite cyl wing))
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;; unite
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; Apply the transforms to the underlying geometry.
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(define fix (entity:fix-transform cyl))
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;; fix
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; Apply the blend CONST_RADIUS attribute to all edges
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; of the wing-cylinder intersection.
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(option:set "raysize" (/ r 2))
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;; 2
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; Select the edge(s) to be blended.
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(define round_edge (pick:edge (ray (position 0 0 0)
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(gvector 0 -1 1))))
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;; round_edge
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; Find all the edges that join smoothly.
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(define smooth-edges
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(blend:get-smooth-edges round_edge))
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;; smooth-edges
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; Attach a constant radius blend attribute to each
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; edge in the list.
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(define blend2
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(blend:const-rad-on-edge smooth-edges 4.5))
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;; blend2
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; Now, pick the front rounded edge.
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(define currEdge (list-ref smooth-edges 1))
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;; currEdge
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; OUTPUT Original
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; Create a cross curve.
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(define cross-curve
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(blend:make-cross-curve currEdge 1.0))
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;; cross-curve
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; Create an edge from the curve.
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(define new_edge (edge:from-curve cross-curve))
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;; new_edge
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; Render the image.
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(render)
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;; ()
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; OUTPUT Rendered
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Figure 2-8. blend:make-cross-curve
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