OneSpace Designer: ME10 Dynamic Drafting MI Interfacing
The Geometry Elements section contains entities that
define the simple geometric elements used in drafting.
These elements include lines, arcs, and circles.
The entities do not contain coordinates. Instead, the entities
contain pointers to P
in the Geometry Points section.
There may also be pointers to the Simple Properties
section, for example to Associated Text Properties
(ASSP
).
When reading this section, note the following:
- The Line Width attribute data refers to both
PENSIZE
and LINESIZE
depending on whether the value is positive or negative:
An arc is a circular line drawn from the begin point to
the end point around the center point. The arc
orientation determines which direction the arc is
drawn, clockwise or counterclockwise.
The begin point, end point, or center point must not
coincide.
Figure 36. Pointer Tree for ARC
ARC | Entity Type.
|
n+ | Entity Sequence Number.
|
n+ | Color.
|
n+ | Line Type.
|
n+ | Line Width.
|
n+ | Display.
|
n+ | Property Count.
|
PTR | First Property Pointer.
|
: |
|
PTR | Last Property Pointer.
|
PTR | Pointer to Arc Center Point.
|
PTR | Pointer to Arc Begin Point.
|
PTR | Pointer to Arc End Point.
|
[0,1 ] | Arc Orientation. Determines the
direction in which the arc is drawn from
the arc begin point to the arc end
point.
|
| 0 Anticlockwise (mathematical positive).
|
| 1 Clockwise (mathematical negative).
In ME10, the arc orientation is always 0 .
|
|~ | End of Entity.
|
A spline consists of a series of one or more spline
segments, which are polynomials, joined end to end so
that the parametric gradients are continuous across the
joints. A mathematical description of the Parametric
B-Spline is given in Appendix B.
Figure 37 shows a simple spline with its control polygon.
Points on the spline curve are called interpolation points,
points on the control polygon are called control points.
Figure 37. Spline Components
The Start Point is the beginning of the first spline segment, and the
End Point is the end of the last spline segment.
Figure 38. Pointer Tree for BSPL
BSPL | Entity Type
|
n+ | Entity Sequence Number
|
n+ | Color
|
n+ | Line Type
|
n+ | Line Width
|
n+ | Display
|
n+ | Property Count
|
PTR | First Property Pointer
|
. |
|
. |
|
. |
|
PTR | Last Property Pointer
|
n+ | The order of the B-spline.
|
[0,1,-1 ] | Open/closed flag:
0 false, the B-spline is open
1 true, the B-spline is closed and not periodic
-1 true, the B-spline is closed and periodic.
|
REAL | Parameter value of first visible point on spline.
|
REAL | Parameter value of last visible point on spline.
|
PTR | Pointer to the start point of the spline.
|
PTR | Pointer to the end point of the spline.
|
n+ | Number of control points.
|
PTR | Pointer to the first control point.
|
. |
|
. |
|
. |
|
PTR | Pointer to the last control point.
|
n+ | Number of knot vector entries.
|
REAL | First knot vector entry.
|
. |
|
. |
|
. |
|
REAL | Last knot vector entry.
|
n+ | Number of curve points.
|
PTR | Pointer to the curve point
|
REAL | Parameter value of curve point
|
n+ | Type of condition at this point
|
| 0. no condition
|
| 1. tangency condition
|
| 2. curvature condition
|
| 3. tangency and curvature condition.
|
REAL | Tangency angle at this point. The angle is measured with respect to the horizontal x-axis, in the units defined in the Setup section.
|
REAL | Weight of the tangency condition (>=0.0)
|
| The weight can be imagined as an attraction of a magnet on the spline (i.e. how strong the spline nestles against the tangent).
|
REAL | x - value of curvature vector.
|
REAL | y - value of curvature vector
|
| The curvature vector points to the center of the curvature circle, its length is defined as 1 / radius of curvature circle
|
| (Zero curvature is indicated as zero vector).
|
A construction circle is an auxiliary circle that
helps to set up geometry. It is defined by a center
point and radius.
Figure 39. Pointer Tree for CCIR
CCIR | Entity Type
|
n+ | Entity Sequence Number
|
n+ | Color
|
n+ | Line Type
|
n+ | Line Width
|
n+ | Display
|
n+ | Property Count
|
PTR | First Property Pointer
|
: |
|
PTR | Last Property Pointer
|
PTR | Pointer to Circle Center Point
|
REAL | Radius of Circle, must be greater than zero
|
|~ | End of Entity
|
A chamfer is a straight line that removes the sharp corner
between two intersecting elements. The distance between the two
end points of the line must not be zero.
Apart from the entity name,
this entity has the same syntax as the line entity (LIN
).
The appearance of the chamfer entity in the MI file,
instead of the line entity, indicates that the line has
a special use.
Chamfers are not used by ME10. During load, a CHA
is
converted to a LIN
entity. During store, only LIN
is
stored.
Figure 40. Pointer Tree for CHA
CHA | Entity Type
|
n+ | Entity Sequence Number
|
n+ | Color
|
n+ | Line Type
|
n+ | Line Width
|
n+ | Display
|
n+ | Property Count
|
PTR | First Property Pointer
|
: |
|
PTR | Last Property Pointer
|
PTR | Pointer to First Point
|
PTR | Pointer to Second Point
|
|~ | End of Entity
|
A circle is defined by a center point and a point on
the circumference. The center point and circumference
point must not coincide.
Figure 41. Pointer Tree for CIR
CIR | Entity Type
|
n+ | Entity Sequence Number
|
n+ | Color
|
n+ | Line Type
|
n+ | Line Width
|
n+ | Display
|
n+ | Property Count
|
PTR | First Property Pointer
|
: |
|
PTR | Last Property Pointer
|
PTR | Pointer to Circle Center Point
|
PTR | Pointer to Circle Circumference Point
|
|~ | End of Entity
|
Defines a construction line.
Figure 42. Pointer Tree for CLIN
CLIN | Entity Type
|
n+ | Entity Sequence Number
|
n+ | Color
|
n+ | Line Type
|
n+ | Line Width
|
n+ | Display
|
n+ | Property Count
|
PTR | First Property Pointer
|
: |
|
PTR | Last Property Pointer
|
PTR | Pointer to the Foot Point. This is a point on the
line.
|
2×REAL | X,Y Components of Orientation Vector,
giving the direction of the construction
line passing through the foot point.
|
REAL | Z-Coordinate of Orientation Vector.
Only exists if the Global Space
Dimension Switch is set to 3D .
|
|~ | End of Entity
|
A fillet is a circular arc connecting two other
elements in a tangential manner, so that a sharp edge
formed by intersection of the two elements is
eliminated. The arc is drawn in a clockwise or
counterclockwise direction from a begin point to an end
point, around a center point. None of these points must
coincide.
Apart from the entity name,
this entity has the same syntax as the arc entity (ARC
). The
appearance of the fillet entity in the MI file, instead
of the arc entity, indicates that the arc has a special
use.
Figure 43. Pointer Tree for FIL
FIL | Entity Type
|
n+ | Entity Sequence Number
|
n+ | Color
|
n+ | Line Type
|
n+ | Line Width
|
n+ | Display
|
n+ | Property Count
|
PTR | First Property Pointer
|
: |
|
PTR | Last Property Pointer
|
PTR | Pointer to Arc Center Point
|
PTR | Pointer to Arc Begin Point
|
PTR | Pointer to Arc End Point
|
[0,1 ] | Arc Orientation. Determines the
direction in which the arc is drawn from
the begin point to the end point.
|
| 0 Counterclockwise (mathematical positive)
|
| 1 Clockwise (mathematical negative)
In ME10, the arc orientation is always 0 .
|
|~ | End of Entity
|
This entity defines a straight line drawn between two
points, known as the begin point and end point. These
two points must be different.
Figure 44. Pointer Tree for LIN
LIN | Entity Type
|
n+ | Entity Sequence Number
|
n+ | Color
|
n+ | Line Type
|
n+ | Line Width
|
n+ | Display
|
n+ | Property Count
|
PTR | First Property Pointer
|
: |
|
PTR | Last Property Pointer
|
PTR | Pointer to Line Begin Point (P )
|
PTR | Pointer to Line End Point (P )
|
|~ | End of Entity
|
A polyline is a set of straight lines connecting a
series of points. In ME10/30 they are used to define the boundary
of a manual hatch area, so they are not visible on the screen.
If a polyline is
used for hatching, the Hatch Flag must be set to 1
.
Figure 45. Pointer Tree for PLN
PLN | Entity Type
|
n+ | Entity Sequence Number
|
n+ | Color
|
n+ | Line Type
|
n+ | Line Width
|
n+ | Display
|
n+ | Property Count
|
PTR | First Property Pointer
|
: |
|
PTR | Last Property Pointer
|
[0,1 ] | Hatch Flag. Specifies whether or not the
polyline is used for hatching.
|
| 0 Not used for hatching
|
| 1 Used for hatching
|
n+ | Number of Points in Polyline
|
PTR | Pointer to First Point of Polyline
|
[0,1 ] | Pen Up Flag. Allows for gaps in the polyline.
|
| 0 Pen is down. Line is drawn to next point.
|
| 1 Pen is up. Line is not drawn to
next point.
|
PTR | Pointer to the Last Point of Polyline
|
[0,1 ] | Pen Up Flag
|
Geometry points can be highlighted by the use of
polymarkers such as small squares, circles and triangles.
Only one Geometry Point is referenced, so a
separate polymarker entity is required for each marked
point.
Note that the PMA entity may also contain a pointer to
a DZP (Dimension Zero Point) property in the Property Data section.
Figure 46. Pointer Tree for PMA
PMA | Entity Type
|
n+ | Entity Sequence Number
|
n+ | Color
|
n+ | Marker Type. The following table gives
the values corresponding to the different markers.
- 1 = dot
- 2 = plus
- 3 = asterisk
- 4 = circle
- 5 = diagonal cross
- 6 = triangle
- 7 = square
- 8 = diamond
- 9 = zero
|
n+ | Line Width
|
n+ | Display
|
n+ | Property Count
|
PTR | First Property Pointer
|
: |
|
PTR | Last Property Pointer
|
n+ | Point Count. Number of points to be marked by the
polymarker. This will be 1 in the MI files produced by
ME10.
|
PTR | Pointer to First Point
|
: |
|
PTR | Pointer to Last Point
|
Note
The description in this section refers to cubic splines and is
included for convenience.
Refer to BSPL (Spline) earlier in this chapter for B-spline descriptions.
A spline consists of a series of one or more spline
segments, which are polynomials, joined end to end so
that the parametric gradients are continuous across the
joints.
The splines described here contain a damping factor
that affects their rigidity.
Four different types of spline are available in MI,
each with different boundary conditions at the Start
Point and End Point. The Start Point is the beginning
of the first spline segment, and the End Point is the
end of the last spline segment, as shown in the figure.
Figure 47. Components of a Splinee
Figure 48. Pointer Tree for SPL
SPL | Entity Type
|
n+ | Entity Sequence Number
|
n+ | Color
|
n+ | Line Type
|
n+ | Line Width
|
n+ | Display
|
n+ | Property Count
|
PTR | First Property Pointer
|
: |
|
PTR | Last Property Pointer
|
n+ | Number of Points in Spline. Must be at least 3 .
|
[14 ] | Spline Type. The values have the
following meanings:
- Natural. The second derivatives at
the Start Point and End Point are
equal to zero.
- Tangential. The angles at the Start
Point and End Point are specified.
The values are given in the
parameters below. See Start Angle
and End Angle.
- Periodic. The first derivatives at
the Start Point and End Point are
identical. Also, the second
derivatives at the Start Point and
End Point are identical.
- Cyclic. Identical to Spline Type
3 ,
with the additional condition that
the Start Point and End Point are
equal.
|
REAL | Start Angle
|
REAL | End Angle
|
| The start angle and end angle are only
used for Spline Type 2 , and will have a
value of 0 for other spline types. They
are measured with respect to the
horizontal X axis, in the angle units
defined in the Setup section.
|
REAL | Damp Value for First Point of Spline
|
PTR | Pointer to First Point of Spline
|
REAL | Damp Value for Second Point of Spline
|
PTR | Pointer to Second Point of Spline
|
: |
|
REAL | Damp Value for Last Point of Spline
|
PTR | Pointer to the Last Point of Spline
|
| The damp values specified above are the
values of a parameter in the spline
equation. This parameter affects the rigidity of
the spline segment beginning at the
specified point. See the description of
spline equations in Appendix B.
|
| The damp values must be either zero or positive.
|
| The damp value for the last point in the
spline has no effect because there is no
spline segment to follow.
|