GEOMETRY FILLET LINE [lnam1] lnam2 lnam3 radius [divn] [pnam] [MODIFY]

    

This command is used to define a fillet. A fillet (which is an arc line) can be created either as a separate entity or joined to the geometry from which it was defined. Where the fillet is joined to existing geometry, this old geometry is modified and any higher order geometric entities or line combinations associated with the filleted region are deleted.

lnam1 = name of new fillet line to be created or name of an existing arc or straight line. If no name is given a name will be automatically created.

lnam2 = name of an existing straight line or arc to be filleted. /PICK and a cursor hit to select the line or arc.

lnam3 = name of 2nd existing straight line or arc to be filleted. /PICK and a cursor hit to select the straight line or arc.

radius = the fillet radius.

divn = integer which specifies how many nodes are to be placed along the fillet. If omitted a default of four divisions (ie Five nodes) is assumed. The default number of divisions can be reset using the command MESHING DIVISION DEFAULT.

pnam = name of an existing (guide) point used to indicate which intersection to choose (with arcs there may be two possible intersections) and which quadrant of that intersection to fillet (see note 2). /PICK and a cursor hit to select the guide point.

MODIFY = to indicate that the existing lines will be modified to join the fillet, the default is for the original geometry not to be modified (see note 3).

 

Figure 2.68: Definition of a fillet with and without the MODIFY option

Return Level: GEOMETRY FILLET

Notes:

1.

Limitations
The two lines to be filleted may be straight lines or arcs and may be joined at one end, both ends, or completely separate. The fillet will not be re-calculated if either of the defining lines are themselves re-defined.

2.

Use of the Guide point
A guide point may optionally be defined and must already exist. This point is used to define the intersection region in which to place the fillet; for example a straight line, when extended infinitely, may intersect an arc at two points and a fillet could be placed near either of these two points. The guide point is also used to define the quadrant around an intersection region in which to place the fillet; where two lines cross, a fillet could be placed in any of the four quadrants. The guide point must not be placed on either of the lines.

Where the guide point is omitted, a guide point is guessed and the fillet calculated on the basis of this guess. Where the two existing lines are not joined, the guide point is placed mid-way between the line end points which are furthest appart. Where the two existing lines are joined at one point, the guide point is placed mid-way between the ends which are not joined. Where the two existing lines are joined at both ends the guide point is placed mid-way between the mid-point of each line.

The guide point is only used internally and it will not be created as part of the filleting command.

3.

The MODIFY option
The MODIFY option may be used to join the ends of the existing lines to the new fillet line; the default is to simply create a new fillet which is not connected to anything else. Where the MODIFY option is used, one point from each of the original lines will be modified and used as an end point for the fillet. The point nearest the fillet will be modified. Any line combinations or surfaces (and any higher order entities which depend upon them) associated with the original lines will be deleted when the MODIFY option is used.

4.

Effect of tolerance
The filleting calculation is sensitive to the model tolerance. For example, if the distance between the guide point and one of the existing lines is less than the model tolerance the point will be considered to lie on the line and an error will occur.

5.

Use with existing lines
Where lnam1 is an existing line it will be modified to conform to the new fillet definition. Any line combinations or surfaces that reference lnam1 will be deleted (see note 3).

Examples:

1.

GEOMETRY FILLET LINE L1 L2 9

Create a radius 9 fillet between lines L1 and L2 with the default number of divisions.

2.

GEOMETRY FILLET LINE L1 L2 9 M

Create a radius 9 fillet between lines L1 and L2 and join the ends of L1 and L2 to the fillet.

3.

GEOMETRY FILLET LINE LNEW L1 L2 9 8

Create a radius 9 fillet called LNEW between lines L1 and L2 with 8 divisions.

4.

GEOMETRY FILLET LINE LNEW L1 L2 9 M 8 P3

Create a radius 9 fillet called LNEW between lines L1 and L2 with 8 divisions in the region defined by point P3 and join the nearest ends of L1 and L2 to the fillet.

See also the following commands

'LABEL GEOMETRY LINES'
'UTILITY DELETE LINES'
'UTILITY TABULATE GEOMETRY LINES'
'VIEW GEOMETRY'

 

Figure 2.69: A typical filleting application