The data entry and edit window is shown below.
Function
name – A function name is
entirely optional. It is used to title the graph window when the
function is plotted.
The
function – This should be entered
in standard BBC Basic format. All characters will be converted to
upper case before the function is evaluated. The entered function is
passed to the Basic function EVAL when the data file is created.
X symmetrical about
zero and Y symmetrical about
zero – If this is ticked then the
maximum/minimum value is entered in the writable field to the right. If
unticked, then both the minimum and maximum values of x or y must be entered
in the appropriate writable fields.
X values are in
degrees and Y values are in
degrees – When evaluating functions
such as sin or cos under Basic, the argument is specified in radians rather
than degrees. If this is ticked, then 3DFNEdit will assume the values
entered are in degrees, and will convert them to radians before evaluating
the function.
Number of
steps – This determines the
number and size of increments used to cover the range of x and y
values from the minimum to the maximum value. When a small number of
steps is used the data file will be smaller, and the surface will plot
much faster, although the resulting graph will not be as smooth. The
number of steps can be changed using the popup menu button to the
right of the display. The values may be set from 20 to 80.
Edit overwrites
original surface – When entering
data for the creation of a new data file this option will be shaded
and not selectable. However, if the data has been transferred back
from a graph display in Surface, then this option becomes available.
In this situation, if the option is ticked, then plotting the edited
data will result in the original graph being replaced. On the other
hand, if the option is unticked then the edited data will be displayed
in a new window, allowing a direct comparison of the two surfaces.
Close – When this
button is clicked the window will be closed without creating a
datafile. The values entered will be retained.
Clear – When this
button is clicked, all the data in the window will be cleared, ready
for the details of a new function to be entered.
Plot – When this
button is clicked, 3DFNEdit will try to send the evaluated function
data directly to !Surface or !3DPlotter for display, via the wimp
message data load protocol. One of these applications must be active
for this to work, otherwise !3DFNEdit will complain. The function
evaluation and subsequent display requires a lot of processing, so it
may be some seconds before the display appears on old hardware.
Data entry window menu
The menu attached
to the data input window is shown to the right. It has only two
options.
Save – This leads to
a standard Save as dialogue which allows the
evaluated function to be saved in text (ASCII) format. Such saved
files may be reloaded into !3DFNEdit by drag and drop to allow further
editing. They may also be loaded into !Surface or !3DPlotter to
display the function as a surface graph.
Plot – has the same
action as the Plot button at the bottom of the
window, i.e. it will send the data file directly to the
surface plotting application (Surface or 3DPlotter) provided one of
them is running.
Info – this leads to
the standard information window.