2.napa online manuals 2009

An explicitly defined point could be regarded as the smallest element of geometrical definitions. Where useful, a pointcan be stored as a named object in the database and, for example, used in the definition of curves. Alternatively, thepoints can be added directly to the curve definitions. This chapter will, however, concentrate on the definition ofcurves, whereas point objects will be given only a brief presentation.

5.1 General about curves

5.1.1 Curve types

In NAPA there are basically two different types of curves: curves with a location surface and those withoutone. The normal curve with a location surface is the basic curve type used in surface definitions. The curvewithout a location surface (the XYZ curve) can also be used in surface definitions.

5.1.2 Curve interpolation algorithms

Two types of interpolation algorithms are used for curves in NAPA. The basic form of the NAPA curve is acubic spline. The standard form of NAPA curves tries to avoid unnecessary inflections that would causediscontinuities in the curvature, i.e. second derivatives. The second method of interpolation (known asM2) has a more continuous curvature.

5.2 Curve definitions (with location surface)

A curve is defined in three or four steps. They are:

naming the curve1.

defining the location surface of the curve2.

defining the shape or projection of the curve on one of the main planes (XY, XZ or YZ)3.

optionally a side condition can also be defined.4.

The syntax of a curve definition is:

CUR name [type] 'explanatory text'

location surface

definition of the shape/projection

[side condition]

The optional type of the curve can be set with the 'type' in the curve definition. The default type is set in thereference system as the GMTP value. The !GMTP command is used to change the value temporarily. Types thatcan be used are:

STD: generate polygons only

SPLINE: generate spline representation (the default in new projects)

M2: use the newer interpolation method, (the same as in XYZ curves); implies SPLINE

O-STD: as STD, but use the old implementation (before 99.1)

Although the location surface has to be defined before the shape of the curve, it might be easier to comprehendthe process in reverse order:

The shape of the curve is first defined in a main plane and then projected onto the location surface.

The location surface can be a main plane (X,Y or Z), a general plane or a surface that is curved in one direction.The next example illustrates the principles of the definition. The shape of the curve is defined on the XZ-planeand it is projected onto a plane defined by three points.

5 Curves and point objects file:///C:/Napa/man/Man091/html/intro/curves/index.html

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In the following example, a curve having its location surface on the XY plane on level Z=0 is created. The curveproceeds from the origin (0, 0) to point (8, 4) through point (4, 2). The curve also has an angle condition atpoint (4, 2), where it has to leave the point at an angle of 0 degrees. We will concentrate on angles morethoroughly in a later chapter.

The following example consists of two curves with the same shape definition. The difference between the curvesis that they have different location surfaces. Curve C1 has a plane location surface at X=-10, whereas C2 has alocation surface of cylinder shape on the positive X side.

CUR c1

X -10

YZ (2, 5), (3.4, 5.5), (5, 5), (6.6, 4.5), (8, 5)

CUR c2

XY (8, 0), (9, 4.8), (11, 8)

YZ (2, 5), (3.4, 5.5), (5, 5), (6.6, 4.5), (8, 5)

As can be seen from the examples shown here, a curve is defined by points. Points can be given

directly with coordinates as in the previous examples, or they can be defined by

adding a reference to an existing curve (the point is the intersection point of the location surface and theexisting curve) or

by using point objects.

For example:


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CUR example3

X, 0

YZ, (1, 1), cur1, (3, 2.5), cur2, cur3, (6, 6)

Note that the command UPDATE is needed to update the references of a curve. For example, if the curve CUR1had been changed in the previous example, the curve EXAMPLE3 should be updated with the command

UPD example3

5.3 Order of definition points

The points of a curve are arranged or sorted automatically unless otherwise specified. They are put in orderaccording to ascending values of the coordinate given by the first character of the shape definition (XY; .... ->points will be ordered according to ascending X). The resulting order of the points determines the direction ofthe curve. This can be understood with the help of the following examples.

The following two lines give the same result when the points are ordered according to the value of X. On thefirst line the values of X are increasing systematically (0, 1, 2) and the points are not reordered. On the secondline, the second point has a lower X value than the first point (1, 0, 2), so the order of the first two points arechanged.

XY, (0, 0), (1, 1), (2, 1.5), .....

XY, (1, 1), (0, 0), (2, 1.5), .....

The order of definition points can be altered by changing the places of the first letters. In the following XY hasbeen changed to YX and the of points on the first line will have the same order as those on the second line afterNAPA has ordered the points.

YX, (2, 1.5), (0, 0), (1, 1), .....

YX, (0, 0), (1, 1), (2, 1.5), .....

Note that changing the order of XY to YX did not change the order of coordinates inside the brackets. The orderof coordinates inside the brackets is always (X, Y, Z). In cases when there are only two values inside thebrackets, the possible combinations are (X, Y), (X, Z) or (Y, Z).

The automatic ordering can be prevented with option * . The following example demonstrates the effect of theoption.

CUR example1

Z, 0

XY, *, (2, 2), (3, 4), (4.5, 3), (3.5, 1), (2, 2)

CUR example2

Z, 0

XY, (2, 2), (3, 4), (4.5, 3), (3.5, 1), (2, 2)


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If points have the same key (ordering) values, the points will be sorted according to the order of appearance.

5.4 Angles

Curves can be defined not only by points but also by angles connected to the points. The following drawingsshow how angles are interpreted by NAPA. The same applies to all main coordinate planes (XY, XZ and YZ).

Let us now the use of angles. The following curve is defined as:

YZ, A, /45, 0/, B, /60, C, ...

This should be interpreted as: 'start from point A at an angle of 45 degrees, then enter point B at an angle of 0degrees and leave point B at an angle of 60 degrees, then enter point C without any angle condition'. The sideon which the slash (/) is located reflects whether the curve is 'leaving' the previous point or 'entering' the nextpoint. For example:

A1/, P, /A2

'A1' gives the angle before point P and 'A2' after it. Note carefully: 'before' and 'after' depend on the directionof the curve, which may be different from the order in the record.

For example:

XY, A, /45, 0/, B, /60, C, D, /-30, E

Should be interpreted as:

/45 from A at an angle of 45 degrees

0/ to B at an angle of 0 degree

/60 from B at an angle of 60 degrees

/-30 from D at an angle of -30 degrees


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5.5 Free angles

A free angle at a point means that the curve behaves in the same way as at an end point. A free angle is alwaysvalid on a given side of a point. On the other side of the, point the angle is determined by the free angle unlessotherwise specified. The simplest way of creating a knuckle is to add a free angle on both sides. The symbol ofthe free angle is a minus sign (-).

A special case of the free angle would be a free angle leaving and entering every definition point. In that case itis not necessary to add -/ and /- to every definition point; instead a <> syntax can be used as shown below:

XY, <>, A, B, C, D, E, .....

Before moving on to defining curves interactively on a workstation, let us first examine some examples in orderto get a better idea of the behaviour of curves.

The name of the next curve is 'example1'. It is located on the XY plane at level Z=0; it starts from point (x=15,z=55) and proceeds to point (x=55, z=15).

CUR example1

Z, 0

XY, (15, 55), (55, 15)

CUR example2

Z, 0

XY, (15, 55), (30, 25), (55, 15)


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CUR example3

Z, 0

XY, (15, 55), 0/, (30, 25), (55, 15)

CUR example4

Z, 0

XY, (15, 55), /-45, (30, 25), (55, 15)

CUR example5

Z, 0

XY, (15, 55), (30, 25), /-, (55, 15)


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CUR example6

Z, 0

XY, (15, 55), -/, (30, 25), /-, (55, 15)

CUR example7

Z, 0

XY, (15, 55), -/, (20, 30), (30, 20), /-, (55, 15)

CUR example8

Z, 0

XY, <> (15, 55), (20, 30), (30, 20), (55, 15)


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CUR example9

Z, 0

XY, * (10, 35), (35, 60), (60, 35), (35, 10), (10, 35)

CUR example10

Z, 0

XY, * (10, 35), /90, (35, 60), /0, (60, 35), /-90,

(35, 10), /180, (10, 35), /90

CUR example11

Z, 0

XY, (15, 55), (30, 20), /-, (55, 15)


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CUR example12

Z, 0

YX, (15, 55), (30, 20), /-, (55, 15)

We draw your attention particularly to the difference between examples 11 and 12. The only difference betweenthe definitions is that the shape definition part in example11 begins with XY, while example12 has it in reverseorder. The curves, however, look completely different. Alteration of the identifier from XY to YX causes the pointsto be ordered according to an increasing Y instead of an increasing X. In this case the definition reversed thedirection of the curve.

5.6 Intersection points between curves

When a curve refers to another curve and there are several possible intersection points, all intersection pointsare used. If only some of the points are needed, or if one has to add different angles to the points, it isnecessary to select between them. A typical example could be frames located in the area of the bulbous bow, inwhich case there actually are two separate frames required - one for the bulbous bow and the other for theupper part. In situations of this kind the following syntaxes can be used:

STEM/Z<5

STEM/Z>5

STEM/Z=#5

These examples are interpreted so that

STEM/Z<5 means 'use the intersection point where the Z coordinate is less than 5 metres'

STEM/Z>5 means 'use the intersection point where the Z coordinate is more than 5 metres'

STEM/Z=#5 means 'use the intersection point where the Z coordinate is nearest 5 metres'

The following example represents this situation. There are two frames needed at X=201 metres - one for thebulbous bow and the other for the upper part above waterline Z=10. TDWL (draught of design waterline) of theship in question is 10 metres and the upper part of the bulb is very close to this level.The FRBLB curve refers inthis example to curve TF1, which is not drawn in the illustration but is a curve ending at the foremost point ofthe bulb.


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This is also a typical problem when the flat bottom or the flat side curves refer to the mainframe and to the stemcurve or the deck curve. Please see the second example on the next page.

CUR stem; y, 0

XZ * frf, -/, (195, 0), 90/, (210, 5.74), 180/,

(204, 9), (202.7, 9), (200, 10), /50, (212.5, 25)

CUR frblb; x, 201

YZ * 0/, stem/z=#10, -90/, tf1, 180/, stem/Z<5

CUR frf10; x, 201

ZY 50/, stem/z>10, 60/, deckf

CUR fsf

Y, 6.5

XZ 0/, frf/z=1.8, (65, 2.2), 65/, deckf/x=72

SC P

CUR fbf

Z, 0

XY 0/, frf/y=4.7, (65, 4.65), stem/x=80

SC P

5.7 Side conditions

A side condition describes the behaviour of the surface near a curve. Its use is not compulsory, as the sameeffect can be achieved by adding an angle condition to each intersecting curve separately. It is, however, a veryefficient and convenient tool for the purpose and its use is highly recommended, at least in the following threecases. Thus the most important side conditions are:

SC P = the limiting curve for a flat plane

SC M = the main frame

SC -//- = a free angle in & out (knuckle)

CUR frm

X 50

YZ (0, 0), -/, (8, 0), (10, 2), /-, (10, 12)

SC M


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The above four lines define the main frame. The frame is located at X=50 metres, it has a bilge radius of 2metres and ends at the deck level at Y=10 and Z=12 metres. Side condition M means that the normal of thesurface is perpendicular to direction X.

CUR frf

X, 62

YZ (0, 0), -/, (4.7, 0), (6.5, 1.8), /-, (6.5, 11.5)

SC M

CUR fsf

Y, 6.5

XZ 0/, frf/z=1.8, (65, 2.2), 65/, deckf/x=72

SC P

CUR fbf

Z, 0

XY 0/, frf/y=4.7, (65, 4.65), stem/x=80

SC P

CUR knf

XZ, (68, 7.1), (85, 8.5)

XY fsf, -30/, (81, 3.1), -90/, stem

SC -//-

The above example shows the most common ways of using the side conditions. More alternatives are, however,availabl,e which is demonstrated in the following. If you have no earlier experience of defining geometric objectswith NAPA, please skip the following examples as well as the chapter TANGENT FUNCTION, and continue on tothe CURVE/CURVE chapter.

CUR C1; Z 0; XY (0, 0), (10, 0)

CUR C2; Z 5; XY (0, 6), (10, 10)

CUR C3; Z 10; XY (0, 8), (10, 10)

CUR C4; X 0; YZ C1, C2, C3

CUR C5; X 3; YZ C1, C2, C3

CUR C6; X 7; YZ C1, C2, C3

CUR C7; X 10; YZ C1, C2, C3

In the following we will add a side condition SC *X=0 to curve C1. This side condition means that every curveentering or leaving curve C1 is forced to have an angle of 0 degrees on the YZ plane, i.e. the X-projection. The


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other side condition added is SC *X=90 to curve C3. This consequently means that every curve entering orleaving curve C3 will have to have an angle of 90 degrees.

We will also add side conditions SC -//- and -//- - to curve C2. Side condition -//- means that the curve inquestion is a knuckle curve, i.e. every curve intersecting this curve will have free angle both leaving and enteringcurve C2.

Side condition -//- - means 'a free angle before the curve but no side condition after the curve'. The figures bestillustrate the changes caused by side conditions.

CUR C1; Z 0; XY (0, 0), (10, 0); SC *X=0

CUR C2; Z 5; XY (0, 6), (10, 10)

CUR C3; Z 10; XY (0, 8), (10, 10); SC *X=90

CUR C4; X 0; YZ C1, C2, C3

CUR C5; X 3; YZ C1, C2, C3

CUR C6; X 7; YZ C1, C2, C3

CUR C7; X 10; YZ C1, C2, C3

CUR C1; Z 0; XY (0, 0), (10, 0)

CUR C2; Z 5; XY (0, 6), (10, 10); SC -//-

CUR C3; Z 10; XY (0, 8), (10, 10)

CUR C4; X 0; YZ C1, C2, C3

CUR C5; X 3; YZ C1, C2, C3

CUR C6; X 7; YZ C1, C2, C3

CUR C7; X 10; YZ C1, C2, C3

CUR C1; Z 0; XY (0, 0), (10, 0)

CUR C2; Z 5; XY (0, 6), (10, 10); SC -//--

CUR C3; Z 10; XY (0, 8), (10, 10); SC *X=90

CUR C4; X 0; YZ C1, C2, C3

CUR C5; X 3; YZ C1, C2, C3

CUR C6; X 7; YZ C1, C2, C3

CUR C7; X 10; YZ C1, C2, C3


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5.8 Tangent function

NOTE: It is not recommended to proceed further with this chapter unless you have first done some basic curvedefinition exercises.

A tangent function is a generalized side condition allowing an angle that varies along the curve to be defined.The definition of a tangent function can rely on explicit angles or on curves intersecting the one it belongs to,the owner curve. For this reason, the tangent function is defined as an independent object.

Intersecting curves do not automatically use angle conditions defined by a tangent function unless syntax */ isused. Syntax */ means: 'enter the curve at an angle defined by the tangent function'. The basic definition of atangent function could be:

TGF curve

XT (0 20) (10 60)

which is to be interpreted as: 'The normal of a surface along the curve is such that at X=0, intersecting curveshave to enter the curve at an angle of +20 degrees (on the YZ plane) and at X=10, the corresponding angle is+60 degrees. Between these points the angle is interpolated.' See the following example in which this tangentfunction has been added to curve C2.

CUR C1; Z, 0; XY (0, 0), (10, 0)

CUR C2; Z, 5; XY (0, 6), (10, 10)

TGF C2

XT (0, 20), (10, 60)

CUR C3; Z, 10; XY (0, 8), (10, 10)

CUR C4; X, 0; ZY C1, */, C2, C3

CUR C5; X, 3; ZY C1, */, C2, C3

CUR C6; X, 7; ZY C1, */, C2, C3

CUR C7; X, 10; ZY C1, */, C2, C3

Another alternative (and quite usual) method of defining a tangent function is to use previously defined curves.In the next example, we will define a tangent function for a deck by using a couple of previously defined curves.

TGF deckf


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XT frm, -/, fsf, frf8, (175, 63), sn, /-, (190, *Y=53)

In this example, attention needs to be paid to several points. First is the mixed use of explicitly defined angles(175, 63) and references to other curves (such as FRF8). The normal of the surface at the intersection pointbetween curves DECKF and FRF8 is defined by FRF8. Second, a tangent function behaves in the same way as acurve, and it can even be plotted with the command

PLOT TGF deckf

This explains why free angles entering (-/) and leaving (/-) points can be used in this connection. The first freeangle means that the tangent function between FRF and FSF will be a straight line, while the second free anglemeans the tangent function behaves between FRM and SN as if the SN were the last point in the definition.

The third thing of the previous example that should be noted, is that angles can be defined even in projectionsother than that of a default. The second line in this example begins with XT; thus the default of the followingdefinitions is that the first number inside the brackets stands for the X coordinate and the second numberrepresents the angle in the YZ plane.

Additional useful examples of the use of tangent functions can be found in the chapter on hull definition.

5.9 Curve / curve expression

A curve/curve expression has two functions in NAPA:

In a curve definition, the syntax curve/curve can be used to designate a point as the intersection betweentwo curves.

1.

The starting angle of the curve is defined so that it shares the tangent plane implied by the referencedcurves.

2.

The second function is especially important because otherwise internal inconsistency is easily created by havingthree curves meet at a given point. Note that the curve/curve syntax should be given in both the location surfaceand the shape.

Let us have a closer look at this with the help of an example.

CUR wlf1

Z stem/frf10

XY (80, 10), /0, stem/frf10


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In this example, the second line (Z, STEM/FRF10) means that the location surface is an XY plane at the Z levelon which curves STEM and FRF10 have an intersection point. The same syntax on the third line means that thecurve is forced to end at STEM, at an angle which is defined by the current normal of the surface.

5.10 Point objects

A point object is the simplest possible object in NAPA. The basic syntax of a point object is:

POINT name (x, y, z)

A point can also be defined by:

translating a new point from an existing point

defining a point on a curve

using an intersection point of two curves

reflecting another point

Let us create a point object called P1. It will be located at X=27, Y=3 and Z=4.5. Then we will create three newpoints (P2, P3, P4) by translating them from point P1.

POINT P1 (27, 3, 4.5)

POINT P2 P1(y+1, z-0.5)

POINT P3 P1(x-1, y+0.5)

POINT P4 P1(X-7)

The coordinates of the points are:

P2 (27, 4, 4)

P3 (26, 3.5, 4.5)

P4 (20, 3, 4.5)

When a new point is located symmetrically on the other side of the Y-plane, it is a reflection of another point.Let us define point P5 with coordinates (27, -3, 4.5):

POINT P5 -P1

The following two points will be defined using curves. Point P6 is located on curve CUR1 at position X=18metres, while point P7 is located at the intersection point of curves CUR1 and CUR2.

POINT p6 cur1/x=18

POINT p7 cur1/cur2

A point object can also be used to check the coordinates of a curve at a specified location. For example, to checkthe coordinates of the KNF curve at X=70:

DEF?>poi test knf/x=70

DEF?>lis test

Point TEST: (70, 6.498, 7.265)

5.11 The XYZ curve

A curve without a location surface is defined as a group of (X Y Z) coordinates. Please note that point objectscan be used but references to other curves always need more information than only the name as there is nolocation surface available to define the point on the curve. An example of the various possibilities of givingpoints:

CURVE EXAMPLE

XYZ (0, 1, 2) P1 FRA1/TA1 FRA/Z=5


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Where

(0, 1, 2,) is the point x=0, y=1, z=2

P1 is a point object

FRA1/TA1 is the intersection point between these two curves

FRA/Z=5 is the point on FRA at Z=5

For more information about the XYZ curve, see the explanation text of XYZ at the C> prompt.

5.12 Exercises

Main frame FRF with the side condition M

CUR frm

X 50

YZ (0, 0), -/, (8, 0), (10, 2), /-, (10, 12)

sc m


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Curve FR2 - no side conditions

CUR fr2

X 80

YZ (0, 0), -/, (2, 0), /- -/, (8, 1), (10, 3), /-,

(10, 12)

Curve STEM

CUR stem

Y 0

ZX frm, -/, (100, 0), (105, 3), 180/, (100, 6), /-,

(110,12)

5.13 First steps in hull definition

5.13.1 Creating a new version

We shall now carry out one practical exercise working with NAPA. We have already defined project P1234in the chapter 'General information about NAPA'. Now we will create a new version, named PATROL, todesign the hull of a small patrol boat.The main dimensions of the boat will be


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LPP = 30 m

BMAX = 6 m

TDWL = 2 m

Main Window : File -> Add Version...

A new version named PATROL has thus been created. The next step is to define the main curves of thefore and aft bodies. We will begin with the fore body.

5.13.2 Setting up the windows (desktop)

The curves are defined in the DEF (definition) subtask of NAPA. To make the whole process moreinteractive and easily modifiable, we will be using the Geometry Window tool and the text editor as ourmain work windows when defining the curves. It is also possible to define the curves directly into theCommand input area of the main window, but then we do not get the same interaction and controlpossibilities.

We start by opening the tools:

Main Window: Tools -> Text Editor ...

Main Window: Tools -> Geometry Window ...

We now have 3 NAPA windows on our desktop. The internal relations between these windows is notimportant. Depending on the resolution and screen size, set up these windows to obtain a suitable


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configuration. NOTE: It is not a good idea to minimize the NAPA Main Window, as it still is used for errormessages, etc. A suggested configuration, that works quite well, is the following:

5.13.3 Using naming standards

When starting the definitions of curves, we will be following a naming standard. Although NAPA will notenforce the use for you of a naming standard, it is very important that one is used.

FRM main frame of a ship without a parallel mid body

FRF main frame of a fore body of a ship with a parallel mid body

FRA main frame of the aft body of a ship with a parallel mid body

DECKM deck curve of the mid body

CLM centre line of the mid body

FSM flat side (side tangent) of the mid body

FBM flat bottom (bottom tangent) of the mid body

STEM stem curve

DECKF deck curve of the fore body

FSF flat side of the fore body

FBF flat bottom of the fore body

KNFn knuckle line in the fore body (KNF1, KNF2, ...)

FRFn frames in the fore body (FRF1, FRF2, ...)

WLFn waterlines in the fore body (WLF1, WLF2, ...)

TFn space curves in fore body (TF1, TF2, ...)

STERN stern curve

DECKA deck curve of the aft body

TRANSOM transom

FSA flat side of the aft body

FBA flat bottom of the aft body

KNAn knuckle line in the aft body (KNA1, KNA2, ...)


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FRAn frames in the aft body (FRA1, FRA2, ...)

WLAn waterlines in the aft body (WLA1, WLA2, ...)

TAn space curves in aft body (TA1, TA2, ...)

5.13.4 Defining the first curves

Let us begin with the definition. The boat is to have a short part of a parallel midbody which starts atX=13 and ends at X=15. We will first define the main frame FRF at X=15. The bilge radius is 1.2 metresand the deck height is 4.4 metres.

Into the work area of the editor, we type:

cur frf

x 15

yz (0 0) -/ (1.8 0)

(3 1.2) /- (3 4.4)

sc m

sur hullf

thr frf

ok

Here we define the main frame 'FRF' and the beginning of the surface HULLF. Details about surfacedefinitions will be available later in this book. NOTE: The OK after the surface definition is important.

After the definitions have been typed, they must be executed. To run this command sequence, we click on

the run icon or select from the menu

Text Editor: File -> Run

For this to work, you will have to be in the correct environment for curve definitions in NAPA, i.e. DEF orDR. When opening the geometry window on the TASK level, the environment will be set to DR. Theenvironment can of course be checked from the prompt in the main window or from the prompt indicatorin any window.

Depending on whether the data echo has been set on or off, you will be able to see the commands beingechoed in the command input area of the main window. To toggle the data echo, please use:

Main Window:-> View -> Data Echo

5.13.5 Visualizing the definition in the Geometry window


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To plot the definitions we will use the Geometry Window. In the Geometry window, we will open thesurface HULLF by writing the name HULLF in the object combo box or by selecting it. The selection is

accomplished by clicking on the open button or by selecting 'Open' from the menu:

Geometry Window: File -> Open ...

To see also the definition points (as above), you have to select 'D ' from the '1st id alternative' drop

down menu, and draw the picture again by clicking on the 'Draw' button

Next we will continue by defining the stem curve into the editor work area. Note that we will also add thedefinition to the surface definition.

cur frf

x 15

yz (0 0) -/ (1.8 0) (3 1.2) /- (3 4.4)

sc m

cur stem

y 0

xz frf -/ (27.3 0)

(29.2 1) /- (32 4.4)

sur hullf

thr frf stem

ok

Run and draw and set the projection to F

Geometry Window: Projection -> F (Front End)


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Add the deck curve, run and draw

cur deckf

z 4.4

xy frf -/ (22 3) (31.7

0.75) /- 90/ stem

sur hullf

thr frf stem deckf

ok

Next we will add the rest of the border and special curves of the HULLF:

cur fsf

y 3

xz 0/ frf/z=1.2 deckf/x=22

sc p

cur fbf

z 0

xy 0/ frf/y=1.8 stem/x=27.3

sc p

cur sn

xz stem/z=2 /58 deckf/x=31.7

zy stem /85 deckf

sur hullf

thr frf stem deckf fsf fbf sn

ok

Definition points can be chosen by selecting 'D' on the '1st id alternative' drop down menu. To see allreference points, select the 'P' alternative.


22 of 24 7/11/2012 11:21 AM

As we have now created the main border curves of the fore body, we can check the HULLF in variousprojections by choosing from the menu

Geometry Window: Projection ->

Note that the projection menu is a tear-off-menu which can be separated from the menu by clicking on thedashed top line. The menu-pane can then be placed anywhere on the desktop.


23 of 24 7/11/2012 11:21 AM

Please note that when choosing Geometry Window: Projection -> Interactive... it is possible torotate the object using the mouse. Pressing the left button and dragging will rotate the object. Pressingthe middle button and dragging will move the object. Clicking on the right button will exit the interactiveprojection mode. NOTE: While in the interactive projection mode (when the cursor is a cross hair), it isimpossible to do any other functions of NAPA.

The definition of a curve can be checked in the Main Window command input area with the command DES{curve}. Points and angles of a curve can be checked with the command LIS {curve}, which shows notonly the definition points but also the coordinates and angles of the intersection points.

DEF?>des deckf

CUR DECKF; Z, 4.4

XY FRF, -/, (22, 3), (31.7, 0.75), /-, 90/, STEM

DEF?>lis deckf

LIST OF CURVE: DECKF

**************************************

X Y Z T SC REF.CURVE

15.000 3.000 4.400 0.00 (M/) FRF

22.000 3.000 0.00 -/

31.700 0.750 -46.40 /-

32.000 0.000 -90.00 90/ STEM


24 of 24 7/11/2012 11:21 AM

2.napa online manuals 2009

Documents

command input

1st id alternative

tangent function

main frame

interactive

xz sc cur

previously

free angle