BLECRB ( edges, type, range1, range2, nprops, props, pvals, blends, nblend,
============================================================================
ifail )
=======
Define a rolling ball blend or chamfer.
Receives:
KI_tag_list_edge *edges --- edges to be blended
int *type --- blend type
KI_dbl *range1 --- blend range 1
KI_dbl *range2 --- blend range 2
<KI_int_nitems> *nprops --- number of blend properties
KI_cod_blec props[nprops] --- array of blend properties
<KI_tag_list> pvals[nprops] --- array of tags of data lists
Returns:
KI_tag_list_edge *blends --- list of edges to which blends
--- have been attached
int *nblend --- number of edges to which blends
--- have been attached
KI_cod_error *ifail --- failure code
Specific errors:
KI_bad_blend_param blend parameter out of range
illegal blend property
KI_general_body general body
Description:
Attaches unfixed blends with the given parameters to a list of edges. Any
existing attributes are replaced by one with the given parameters.
'type' 1 => rolling ball blend
2 => chamfer
The blend ranges are interpreted according to the following table.
blend type | 'range1' | 'range2'
----------------------------------------------------------------------
Rolling ball | radius of rolling ball | ignored
----------------------------------------------------------------------
Chamfer | range 'on left-hand face' | other range
If the blend type is Rolling Ball, 'range1' must be greater than twice the
maximum tolerance of all edges in 'edges' and their associated vertices.
If the blend type is Chamfer, one of 'range1' and 'range2' must be greater
than twice the maximum tolerance of all edges in 'edges' and their associated
vertices.
'props' consists of an array of 'nprops' blend properties, and 'pvals' consists
of a parallel array of tags of data lists for those properties, which can
frequently be null tags. The meanings of the properties and the associated data
are given below.
BLECCL cliffedge blend
associated value in pvals: tag of list containing tag of edge at cliff top.
Creates a blend tangent to the face adjacent to the blended edge and
touching the edge at the 'top' of the cliff. This property is only valid if
only one blend is being created with this call to BLECRB.
This property is only valid for rolling ball blends.
BLECPR propagate flag
associated value in pvals: null tag.
Blend will be propagated over tangent edges, or past other unfixed blends
if the resultant combination of blends at a vertex would be invalid, and
blending the third edge results in a valid combination. The default
behaviour is no propagation.
Note that if a blend does propagate, and you wish to remove the resulting
blend attributes, BLEREM will need to be passed the tags of the edges
propagated on to as well as that of the original edge.
This property is invalid for cliffedge blends.
BLECTL set tolerance
associated value in pvals: real list containing tolerance.
Sets the tolerance for the blended edge. This argument is only allowed
when defining a chamfer surface. The default tolerance is
1000 * modeller resolution.
There are also some tokens relating to overflow behaviour.
The default overflow behaviour of a blend is as follows;
When fixing a blend, it is possible that the blend as defined by its basic
parameters would lie outside the faces adjacent to the edge being blended. If
this is so, the blend must 'overflow'.
If the configuration allows us, we do this by 'smoothly overflowing' and
creating a blend one of whose underlying faces is the one it has overflowed
onto.
If the configuration is unsuitable for this, we try to 'cliff overflow' -
that is replace the appropriate section of the blend by a cliffedge blend
running along the appropriate edges (Cliffedge overflows are only implemented
for rolling ball blends).
If the configuration is unsuitable for this as well, we will then 'notch
overflow' - that is, merely trim the blend by the other faces in the region,
leaving its surface geometry unchanged. If the configuration is unsuitable
for this as well, the blend will not fix.
By default neither cliffedge or smooth overflows will occur when the edge being
overflowed is of the same convexity as the edge being blended.
By default also, cliffedge overflows will not occur at the ends of blends,
except where they meet another blend smoothly.
Overflow Type Prevent Allow when Same Convexity Allow at End
---------------------------------------------------------------------------
SMOOTH | BLECNS | BLECSM | * |
CLIFFEDGE | BLECNC | BLECSC | BLECEC |
NOTCH | BLECNN | * | * |
---------------------------------------------------------------------------
A * means that this behaviour is always possible.
All these tokens have an associated value in pvals of a null tag.
Note that while any combination of these tokens is allowed the preventative
tokens will, of course, negate the efffects of the other overflow tokens.
For further explanation, and examples, of the use of these tokens, please
refer to the blending section of the manual.
BLECRI ribs will be drawn by RRVIND
associated value in pvals: tag of real list containing ribspace.
Where ribspace is the approximate separation of rib lines.
(0 < ribspace < size)
BLECDF draw and fix flag
associated value in pvals: null tag.
Causes the blend to be ignored by BLEFIX, BLECHK and RRVIND, which will
all treat the edges as unblended.
Default behaviour is for an unfixed blend to be fixed, checked and drawn
as required.
Note that that an unfixed blend will only be drawn in RRVIND if BLECDF has
not been set and RRVIND has been called with option RROPUB.
A successful result will produce a new blend attribute. It will return the tag
of the edge(s) to which the blend attribute is attached.
See BLEFIX for making the blends a part of the topology.
Note that an unfixed cliffedge blend will be invalidated if stored between
sessions.
This function is not supported for edges on general bodies.
