PRESENT OPTIONS CONTOUR Mode [Control] [Range]

                          

The PRESENT OPTIONS CONTOUR command allows the user additional controls on the contour plots displayed via the PRESENT CONTOUR command.

Mode Control Range Comments

LINES MODULATE ALL Controls colour modulation

Frequency of line contours (see note 1). OFF

ANNOTATE Frequency Controls how often a line

OFF contour is annotated (see note 2.)

KEYLINE Frequency Controls which line contours

AUTOMATIC are annotated (see note 3).

FILL ALL Controls the result values

MAX [ABSOLUTE] to be considered on an element

MIN [ABSOLUTE] when displaying colour fill

MEAN contours (see notes 4 & 6.) POINT-ID n

EDGES ALL Controls the result values to

MAX [ABSOLUTE] be considered on an element

MIN [ABSOLUTE] when displaying colour edge

MEAN contours (see note 5.) POINT-ID n

LEVELS DEFAULT n Sets the default number of contour levels for the `PRESENT CONTOUR LEVELS [n]' command.

Notes:

1.

Colour Modulation of Line Contours
The command PRESENT OPTIONS CONTOUR LINES MODULATE controls the use of colour modulation for contour lines. The default condition is that contour lines will be drawn in a `FULL' spectrum of colours from red to blue on the basis of the results values, and that the full range of colours on the current graphics device will be used.

Examples:

(a)

PRESENT OPTIONS CONTOUR LINES MODULATE 10

10 colours will be selected for colour modulation.

(b)

PRESENT OPTIONS CONTOUR LINES MODULATE ALL

Depending upon the number of contour lines, the full range of colours will be used for modulation.

(c)

PRESENT OPTIONS CONTOUR LINES MODULATE OFF

Colour modulation will be switched off.

2.

Frequency of Annotation of Line Contours
The command PRESENT OPTIONS CONTOUR LINES ANNOTATE controls the frequency of annotation on contour lines, and is only applicable to line contours.

The default condition is that each contour line is annotated every fifth line segment of its length. This may not always be appropriate, and the user may increase or decrease the frequency of annotation according to the complexity of the model. The annotation is linked to the actual contour values in a legend (see DRAWING CONTENTS LEGEND).

The annotation may be turned off completely by selecting PRESENT OPTIONS CONTOUR LINES ANNOTATE OFF and this is useful when using a large number of coloured contours as in the case of the command PRESENT CONTOURS LEVEL 50. In this case each colour is linked to the contour values in a legend, and these colours will be mapped, depending upon the number of colours that are available with the particular graphics display.

Examples:

(a)

PRESENT OPTIONS CONTOUR LINES ANNOTATE 1

Every contour line segment will be annotated.

(b)

PRESENT OPTIONS CONTOUR LINES ANNOTATE 12

Every twelfth line segment of a contour will be annotated.

(c)

PRESENT OPTIONS CONTOUR LINES ANNOTATE OFF

Annotation will be switched off.

3.

Frequency of Key line Annotation of Line Contours
The command PRESENT OPTIONS CONTOUR LINES KEYLINE allows the user to specify which contour lines should act as key lines for annotation. If the user specifies a key line value of 2 then every other line will be annotated. The default is that all lines, up to a maximum of 26, will be annotated.

Examples:

(a)

PRESENT OPTIONS CONTOUR LINES KEYLINE 4

Every fourth contour line will be annotated. For example if a temperature plot was being produced with a datum of 0 degrees and a step of 25 degrees then only the contours in increments of 100 degrees would be annotated (including 0 degrees).

(b)

PRESENT OPTIONS CONTOUR LINES KEYLINE AUTOMATIC

Keyline control will be switched off, and the program will return to the default condition.

4.

Filled Contours
The command `PRESENT OPTIONS CONTOUR FILL' requests that colour fill be used for contouring. Areas between contour lines are filled with colour, and thus each colour corresponds to a range of result values.

The `ALL' control, which is the default, requests that all the values on the element face be considered and each element face may be contoured in more than one colour depending upon the number of contour levels specified, the number of colours available, and the distribution of results.

The `MAX', `MAX ABSOLUTE', `MIN', `MIN ABSOLUTE' and `MEAN' controls request that the face of an element be filled with a single colour corresponding to the maximum, absolute maximum, minimum, absolute minimum or mean value on the element face (or on the element as a whole when contouring Gauss values). The `POINT-ID n' control requests that the face of an element be coloured with a single colour corresponding to the nth value for the element. For example, if `POINT-ID 3' is specified then for elementwise nodal results the value for the third node (according to the element topology) is used and for elementwise Gaussian results the value for the third Gauss point (according to the order entered into FEMVIEW) is used.

With `PRESENT OPTIONS CONTOUR FILL' applied to model visualisation modes (see VIEW) other than VIEW HIDDEN the faces of the model will be drawn in the order in which the elements occur in the database, so with some models, the faces at the back of the model may be drawn after faces nearer to the observer which will produce a confusing picture.

5.

Edge Contours
The command `PRESENT OPTIONS CONTOUR EDGES' requests that, when drawing the model, the mesh will be drawn in a colour corresponding to the result values on the element. The segments of element edges between contour lines are coloured according to the range of values.

The `ALL' control, which is the default, requests that all the values on the element edge be considered and each element edge may be drawn in more than one colour depending upon the number of contour levels specified, the number of colours available, and the distribution of results.

The `MAX', `MAX ABSOLUTE', `MIN', `MIN ABSOLUTE' and `MEAN' controls request that the edge of an element be coloured with a single colour corresponding to the maximum, absolute maximum, minimum, absolute minimum or mean value on the element edge (or on the element as a whole when contouring Gauss values). The `POINT-ID n' control requests that the edge of an element be coloured with a single colour corresponding to the nth value for the element. For example, if `POINT-ID 3' is specified then for elementwise nodal results the value for the third node (according to the element topology) is used and for elementwise Gaussian results the value for the third Gauss point (according to the order entered into FEMVIEW) is used.

When using `PRESENT OPTIONS CONTOUR EDGES' for contouring elementwise nodal results or material dependent nodal results it will be necessary to apply a small shrink factor if the differences between adjacent elements are to be seen.

6.

Contouring Gauss Point Values
When contouring Gauss point values, the commands PRESENT OPTIONS CONTOUR LINES and PRESENT OPTIONS CONTOUR FILL ALL and PRESENT OPTIONS CONTOUR EDGES ALL will cause the vertex node of an element to be given the result value of its nearest Gauss point. Values at element mid-side nodes are taken as the average of the two appropriate vertex nodes. This, depending on the distribution of results over the model and the contouring command issued, will mean that an element may be contoured in more than one colour. Contours will be discontinuous at element boundaries.

If the mesh is being viewed in filled or shaded mode then only one value per element will be used. This limitation may be overcome by use of the `RESULTS CALCULATE EXTRAPOLATE' command.

The `MAX', `MAX ABSOLUTE', `MIN', `MIN ABSOLUTE' and `MEAN' controls request that a single colour be used corresponding to the maximum, absolute maximum, minimum, absolute minimum or mean Gauss value on the element as a whole. The `POINT-ID n' control requests that a single colour corresponding to the nth Gauss point for the element (according to the order entered into FEMVIEW) be used. The monitor box will show which value has been used.

7.

Contouring Invariant Values
The commands PRESENT OPTIONS CONTOUR LINES, PRESENT OPTIONS CONTOUR FILL ALL and PRESENT OPTIONS CONTOUR EDGES ALL cannot be used with element invariant results as these contouring modes (which may produce modulated contours within an element) require result values at the nodes of an element.

Otherwise, the element is either filled or drawn in a single colour regardless of the specified `Control'. No contour modulation within an element is shown.

See also the following commands

'DRAWING CONTENTS LEGEND'
'PRESENT CONTOUR'
'RESULTS CALCULATE EXTRAPOL'
'RESULTS RANGE EL-RESULT'
'UTILITY SETUP COLOUR'
'VIEW'