[Bf-funboard] contraints - a problem.

Gwyn Perry bf-funboard@blender.org
Wed, 9 Jul 2003 11:44:19 +0100 (BST)

hi everyone,
all of this contraint discussion is very interesting,
almost exactly what i thought the system should be
when NaN first introduced it.
however, one small issue has occurred to me regarding
the replacement of current parenting with "ADD
Loc/Rot/Size" constraints. unfortunately, i don't have
FTP access at the moment and can't post diagrams, so
you'll have bear with me while i try to explain.

using current parenting system:

OBJ_A at xyz 0,0,0 is the parent of OBJ_B at xyz
OBJ_A is rotated 90` around Z, placing OBJ_B at 0,2,0.
so, both objects are rotated 90`, and OBJ_B has moved
two units +X and +Y. OBJ_A has not moved. all objects
are, in effect, components of one grand object.

using proposed "ADD Loc/Rot/Size" constraints:

exactly the same situation, however, as OBJ_A has not
moved, OBJ_B has no location to add, therefore doesn't
move either. Without the linked relationship of
parenting, the constraints would not perform the same
job. an add rotation constraint would have a similar
effect to the "Rotation/Scaling around individual
object centers" button, except as a constraint, not an
interaction option.

In light of this, I would like to propose a complete
"parent" constraint. This would be in addition to the
individual "ADD" constraints (which i think are an
excellent idea)


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