Illusionist - Step by step guide
________________________________

   This article has been included with New Dawn as a text
file, to enable it to be read while using Illusionist. It
may not be distributed seperately from the magazine.

   Welcome to the first of a regular column about the
graphics package Illusionist. Each issue I'll be giving
you a step by step guide showing you how to use this
comprehensive software to produce some great graphics.

   So why choose Illusionist? Firstly, the package is one
of the main rendering programs on the Archimedes, and in
my opinion is only rivalled by Render Bender II, also
produced by Clares. Despite the drawbacks of simply
rendering the objects rather than ray tracing them as in
Render Bender (eg. no shadows or reflections of other
objects), the software allows you to perfect a really good
scene much more easily. The other main benefit is time -
Illusionist will take up to about 1.5 hours on a really
complicated scene, compared to up to 7 hours on Render
Bender.

   The manual and tutorials supplied with the software,
descibe each function of the package really well and so I
will not repeat what is already available. Instead I will
detail some of the techniques which can be used to render
some really professional pictures.

   For this first article, I will start off with a simple
but effective method of designing landscapes suitable
either as art in their own right, or as backgrounds to
other pictures. If you want to jump ahead and see the
finished picture, have a look at Mandel in the graphics
section.


   Before starting, you will need some sort of full screen
picture (mode 12 or 13) to map onto the finished polygons.
I used the excellent Mandy application (from Archimedes
World mag.) to produce a Julia (like a Mandelbrot but
different), but if you can't get hold of any suitable
fractals, just use whatever picture you can get hold of.
See the factfile for info on Mandelbrot programs.

   The aim of this mini tutorial is to produce a
mountainous sort of landscape, and so we will start by
adding the only object we will use - a surface. But first
make sure that the Misc-Objt sides menu option is on at
least 20. This option controls the of polygons that will
be found in each object, by setting the number of sides.
Twenty is a minimum, but don't go much higher than this
unless you have an ARM3 or a lot of patience.

   After setting that option, goto Edit-Add object-Surface
to produce the object that we will be manipulating. Now
press CTRL-P for the Map list, and drag your picture to
number 1. After loading in our picture, we can now map it
onto our surface. Goto the menu : Edit-Material, and click
on the map option until it shows "1" instead of "None". We
also want the surface to be Shiny and Smoothed. After
selecting these, click on update.

   Doing a Render-Mini test, will now show that we have a
flat square with our favourite fractal mapped onto it. The
next stage is to add that "rippley" effect.

   First click on the clear selection icon, and then the
zoom in icon twice. You should now be able to see all of
the green points, but they should fill the bottom right
viewing box, and this is the one we shall now work in.

   Click on the select point option, and then drag the
cursor randomly over the green dots. Try and select about
30% of the dots, but make sure that the majority of the
edge and corner dots are selected. This will prevent
unrealistic straight sides in the final picture. Now
select the move icon, and, working in the top right view
window, drag the selected points up by about 0.5cm on the
screen.

   The first stage of bumpiness is now complete, so goto
the menu: World-View Angle-18, to zoom in the finished
picture view, and then click on the white viewing box. You
should now be able to see the bumpy surface.

   Next, click on the select point icon again, and line
the cursor up in the top right viewing window, so that it
can only select the top line of points. Then repeat the
random selection process described above, which is carried
out in the bottom right window, but this time only select
a small number of points.

   As before, drag the points upwards but by about 0.25cm
on the screen. Check your progress with the white wire
frame window or even with a render-mini test.

   You should by now have got the idea of this selecting
and dragging of points, so now have a go at selecting some
of the lowest points, and dragging them down. Play around
with this until you have a suitably bumpy surface, and
then move onto the next stage: light sourcing.

   Many people think that for a really good rendered
scene, you have to use a large number of lamps and spots,
but this is simply not the case. By using only one lamp
and raising the World-Exposure to about 370, it is easy to
achieve a good variation of light and dark. Now
Illusionist will not render cast shadows, but it will draw
the abscence of light (if you see what I mean!!!) and
thats what we're going to use by positioning the light
source carefully.

   First reduce the World-View angle again and check the
wire frame view until you are satisfied that the picture
is filled suitably. Now position the standard cursor over
the red cross in the centre of the picture and zoom out
twice (all zooms are centered on the cursor). The yellow
cross that you can see is the observer, and the position
of this is crucial when considering light sources. We must
place the light source in a position that will only light
some of the polygons in view. This means positioning the
lamp only just above the height of the surface, and to one
side of the observer (see diagram below).

       ***
       ***
     L


             X

The diagram shows the overhead view, with the asterisks
indcicating the position of the surface, the L being the
lamp, and the X is the observer. Position the cursor as
descibed above, and then goto the menu Edit-Lamps-position
to relocate the default lamp. Now check the picture with a
mini test. This stage is very important, so tinker around
with the lamp's position until you are satisfied.

   After a final Render-Mini test to check colour and
lighting, as well as a Render-Wire frame to check
positioning, you can now render the picture fully. Select
the following options from the Render menu in order to
produce the highest quality picture : Screen off, Closest
fit and Anti Aliasing. You now need to decide on output
mode. Mode 15 is needed for a really good quality pic, but
mode 13 will do if you are in a rush. Multisync mode 21
gives outstanding output for people with Multisync
monitors, but with anti aliasing on, it really does take
at lot longer to render in this mode (and double the disk
space when rendered). Now click on Render-Draw picture and
wait for the results.

   This issue's intro gave a fairly detailed description
of each process, but I don't know if it's really what you
the readers want to see. Please write in and tell me your
views - I'll write what you want to read.


Factfile


Illusionist (and Render Bender II) are available from
Clares micro supplies. Contact Clares for a free catalogue
and demo disk:

Clares
 98 Middlewich Road
  Rudheath
   Northwich
    Cheshire
     CW9 7DA

Tel : 0606 48511


Mandy - the best mandelbrot program - is available on a
back issue of Archimedes World (July 91), and is
reccomended.


Fastbrot - PD mandelbrot util is available from the
Datafile PD for 1.25 (order Utility 1). Use in
conjunction with a screen grabber. Contact:

Datafile PD
 22 Duxford Drive
  Aldergrove
   Co. Antrim
    BT29 4BG


COBRA