PC Format (Spanish) 9/PCF9.iso/share/win31/3dgraph/readme.txt

Text File | 1997-01-01 | 8.0 KB | 190 lines

3D Graph by Jason Melquist

Files needed:

    3dgraph.exe    (the program)
    oldgraphs.sav    (data file)
    readme.txt    (these instructions)

The development of this program came about as a result
of a class I took at Mankato State University, MN: calculus III.
One goal of the class was to be able to graph a function of x
and y in 3 dimentions.  To draw this on 2D paper (the only kind
I know of!!)  was a dificult task if you expected anyone else
to be able to get any perspective of it.  So I wrote this
program to make these graphs easier to view.  Too bad I didn't
write this durring that class but enough cry'n over spilt milk...


FEATURES:

3D Graph allows you to view a graph in three-Dimentions and to
roll the graph around in real time so you can actually SEE the
graph in 3D!  You can adjust many features including:
    the ranges of X, Y, and Z
    the detail of the graph
    auto centering
    save graphs to disk for later viewing
    and much more!

The unregistered version has a handfull of graphs for you to view
and roll around, zoom into/outof, change the ranges, etc....  Once
you register (...only $15!)  you can enter your own formulas...which
of course, is what the program was written for!  The demo version
is just that: a demo.  But you can see the awesome capabilities that
3D Graph offers to the mathematician, student, or anyone interested
in graphing for that reason!

TO GET YOU STARTED:

The interface is simple enough yet extreamly powerfull.  to
start, look at the saved graphs that come packaged with 3D Graph.
To do this, simply choose one of the formulas listed in the
drop-down box in the upper right corner of the program.  You
will see in the graph window, the word "working..." appear for
a moment or two, then a graph will appear there.  "that's nice"
you may say, "but doesn't look very three-dimentional to me."
Well move your mouse to the graph window (the cursor turns into
a four way arrow), press the left mouse button, and drag the graph
around....whoa! NOW your rotating the graph in 3D!
Feel free to take a look at all the saved graphs...and play around
with 'em.  The orientaion of the graph is as follows:
    the x-axis extends twards you as x increases
    the y-axis extends to the right as y increases
    the z-axis extends upwards as z increases


TO ENTER A FORMULA

the formula is in the form of z(x,y) which simply means that the
Z value depends on the values of X and Y.  just as y(x) means that
Y depend on X in a 2D graph.  you have many operators at your
disposal.  of course the standard:
    +,-,*,/,^
are all legal and follow normal order of operations (meaning that
unless parethesis state other wise, ^ operator has priority over
the +,-,*, and / operators and is calculated first.
other operators offered and there syntax:
    operator    meaning        example
------------------------------------------------
    sin        sine        sin(x+y)
    cos        cosine        cos(x+y)
    tan        tangent        tan(x+y)
    abs        absolue value    abs(x+y)
    sqr        sqare root    sqr(x+y)

of course you can use these in combination with other stuff like:
    f(x,y)=sin(x)*cos(y)^abs(x-y)

also available are the constants e and pi
use them any place you would use them normaly such as:
    f(x,y)=sin(x*pi) or
    f(x,y)=e^x-e^y


THE LIMITS OF X,Y, AND Z:

You can change the limits of the viewed graphs by simply
entering new ones in the appropriate box.  If you've worked with
graphing at all, you'll understand that the range of X is denoted:
    -3.14 < X < 3.14
In this example, the range of X is between -3.14 and +3.14
the same is true for the Y range.  the Z range is a little different
because of the nature of graphing a function with the form:
    z(x,y)= ????
the value of Z depends on X and Y.  so the reson for having
a limit for Z is this:  if you were to graph the function:
    z(x,y)=1/sqr(x^2+y^2)
you get a flat graph which as you get closer to the origin, goes to
infinity.  well, dispite the huge (and expensive!!) monitors they are
making now days, they haven't made one that can display infinity
number of pixels (surprize, surprize...)  so 3D graph will graph the
function and then "chop off" any points that lie higher (or lower)
than the z limit you enter.


HOW TO SAVE OR DELETE A GRAPH:

ok, this is about as easy as it gets:  to save a graph that
you have entered into the f(x,y) box....click the "Save Graph"
button.  That's it.  It will save the formula, and limits currently
entered into the appropriate textboxes.  To delete one of the
graphs listed in the "Saved Graphs..." drop-box, simply select(view)
that graph and then click on the "Delete Graph" button.
At anyrate, when you quit the program, all changes to the list will
be saved to disk for the next time you run 3D Graph.

WHAT'S THE "Center graph vertically" CHECKBOX MEAN?

the graph is automatically positioned horizontally in the viewing
window, but for instance the graph of:
    z(x,y)=2000
would graph a flat surface 2000 units up.  If the checkbox is left
unchecked, you would see nothing in the window.  But with this
checked, the center of all points graphed will be calculated and
that center will be in the center of your viewing window.  The
default is to have this feature on (i'm not sure why you wouldn't
want this on ALWAYS, but hey....it's upto you!)


AND THE "Scale graph vertically" CHECKBOX?

It is usefull to have this checked in the following example.  say
you graph the function:
    z(x,y)=x^2+y^2
and you set the Z limit to a large number like 100.  The resulting
graph is narrow but tall, and you will only see a part of it in
the viewing window, to remidy this, make sure this checkbox is
checked, and it will automatically scale the graph so that you can
see the whole thing...keep in mind that this "squashes" the graph
and what you are seeing is NOT porportional.  This fuction too can
be turned off.  so you are asured that every graph you view is
porportionally correct, but it makes viewing tall, skinny graphs
difficult.


THE ZOOM IN/OUT BUTTONS:

These do exactly what you think they do...when a graph is visable,
click on "Zoom In" to get closer to the graph, and "Zoom Out"
to get further away. 3D Graph is automatically calculates the best
view and zoom factor for you but if you want to zoom out or in,
once again, that's up to you.


THE DETAIL SLIDER BAR:

This slider bar determines the resolution of the 3D graph.  The
default value is 10 divisions by 10 divisions.  Drag the slider
to the right and the resolution increases, left and it decreases.
Of course as you increase resolution, you also increase the work
3D Graph has to do and this will slow down the rotation of the graph.
The default value of 10 seems to be the best trade off to start with,
but once you get the graph you'll be able to tell if you should view
it at a higher resolution or not...if you have a Pentium 100Mhz you
can boost up the Detail Slider quite a bit before you notice any
reduction in speed.  The maximum resolution offered it 50 divisions
each way this gives about as detailed a graph as possable.  Of course
you could drag the slider all the way to the left and see 1 division
each way....if ya want...that's what the minimum value is.


I hope you enjoy 3D Graph and I'm always interested in what users
are doing with it!  Feel free to let me know how you like it, any
suggestions you have, or any comments.  As I said before, registration
is only 15$ and unleashes the possabilities of the graphs you can
display.  To register just send $15 to:
    Jason Melquist
    RR1 Box 85B
    Morton, MN 56270
be sure to include your name and address, and for faster registration
send me your email address.

For comments or to contact me personally, you can email me at:
    [e-mail]

This program was released in January of 1997.  Beyond 1997 there will
be newer versions/updates so keep an eye out.  Also since I only have
another year and a half before I graduate from Mankato State U, my
address may well change after that time, if it does, a newer version
will be out....look for it!!