GEOMETRY SWEEP part [name] trnam [divn] [depn] or: ... part [name] [divn] trtype [tr

This command is used to define new parts by sweeping existing ones through a transformation. The transformation can either be previously defined or be defined as part of this command. Selection of the geometry to be swept is either by keyboard or cursor.

part	=	name of an existing point, line, surface or set.
name	=	name of a new point, line, surface or set that will be created by taking a copy
		of 'part' and transforming it according to `trkey'. If omitted FEMGEN will
		automatically generate a new name.
trnam	=	name of the transformation to be used (translation, rotation or scale only, defined
		with CONSTRUCT TRANSFORM).
divn	=	integer which specifies how many nodes are to be placed along the lines that
		are generated from swept points. If omitted the default (as set with
		MESHING DIVISION DEFAULT) is used.
depn	=	dependency control, either DEPENDEN or INDEPEND (the default). If the
		transformation is specified as part of this command then the copy operation can
		only be independent. If DEPENDEN is specified then the geometry of any
		parts created by the GEOMETRY SWEEP command will remain dependent
		on the transformation used in the command and also on the geometry of the
		original part. Thus if the transformation is subsequently redefined in any way
		(e.g. by changing the co-ordinates of one of the reference points used in its
		definition) or the geometry of the original part is changed, then the geometry of
		the parts generated by the SWEEP command will be changed correspondingly.
		If INDEPEND is specified then any parts created by the GEOMETRY SWEEP
		command will be uneffected by subsequent redefinitions of the transformation
		used in the sweep or by changes to the geometry of the original part.
trtype	=	Type of the transformation to be used. (See below).
tr_new	=	name for transform created as part of the copy operation. A new transform name
		will be saved in the database if a name is given for the transform or if the copy
		is defined as being dependent on the transform. The transform created is
		associated with the surfaces and bodies created as part of the sweep operation.
defn	=	Definition of transform (See below).

The GEOMETRY SWEEP command is used to sweep a profile (part) through space to create new objects. The sweep path is determined by the transformation that is used. If it is a pure rotation the sweep will be rotational, otherwise it will be straight.

When the GEOMETRY SWEEP command is applied to a set and the set has more than one type of geometric entity (point, line, surface), only the parts having the highest order entity type (and its constituents) are swept; parts that are in the set with a lower order entity type are simply copied. For example, for a set containing a four sided surface and a fifth (separate) line, the surface is swept to form a body. The fifth line that is not a connected to any surface in the set will be copied, but will not result in the creation of a surface. The same applies to points if lines or surfaces are also in the set.

When a named rotational transform (created with CONSTRUCT TRANSFORM) is used to create a swept surface, the transform is stored as part of the surface definition. Similarly, when the rotation definition is given as part of the GEOMETRY SWEEP command a new transform is created and stored.

The transform used in the sweep operation is also used when a mesh is generated to ensure that nodes are correctly positioned on a surface of revolution and is an essential part of prism bodies generated by sweeping 'region' type surfaces. This dependency can be removed (if required) with the MESHING SHAPE surface BOUNDARY

For a detailed description of the definitions of the four transforms the user is referred to the command CONSTRUCT TRANSFORM. Although translations may be performed using cylindrical or spherical coordinate systems it is recommended that only rectangular systems are used.

The difference between GEOMETRY COPY and GEOMETRY SWEEP is that GEOMETRY SWEEP will not only create the new object 'name', but also connect `part' and `name' with lines (and surfaces) and finally create surfaces or bodies between `part' and `name'. Thus points will create lines, lines surfaces, and surfaces bodies.

Whenever possible, instead of generating new objects, existing ones with the same topology are used. Nodes on polylines are not tested for coincidence with existing nodes. If the check for existing objects is not required then the command CONSTRUCT SPACE TOLERANCE OFF may be used which will have the effect of making the sweep operation quicker.

trtype	defn
TRANSLATE	Two point translation definition OR
	Three offset distances with optional coordinate system
ROTATE	Three or four point rotation definition OR
	Two points and angle of rotation
SCALE	Two point scale definition with a scaling factor plus a second
	optional scaling factor

GEOMETRY SWEEP part [name] trnam [divn] [depn] or: ... part [name] [divn] trtype [tr_new] defn [depn]

GEOMETRY SWEEP part [name] trnam [divn] [depn]
or: ... part [name] [divn] trtype [tr_new] defn [depn]