Aminet 6/Aminet 6 - June 1995.iso/Aminet/gfx/3d/IIUtilities13.lha/IIUtilities/Stars.ReadMe

Text File | 1995-03-30 | 8.5 KB | 197 lines

                             --- Stars V1.3 ---
                                  Feb-1-95
What is it?

 Stars is a program that will generate starfields in TDDD format.
 (Thats the file format for Imagine 3D)

Usage is pretty simple.  All you need to supply is a filename, number
of stars and the distance from the axis that they are to be placed.

 Ex: "Stars Universe.iob 500 XS=160"

This will generate a sphere of 500 stars placed 160 Imagine units from
the axis of the object.  There are more paramaters to further customise
your starfield.  A template can be listed by typing "Stars ?".

The following paramaters will let you completely customise a starfield.
It can be a sphere stretched and shaped in three directions, covered in
a skin of stars or partially or totally filled.  A rectangular shape
can be used instead, or a square or oval based filled or hollow torus.
Stars can als be given many shapes including disks, triangles, squares,
particles and cubes.

File: (Required)

  This is the filename to save the imagine TDDD file to.

S=Stars: (Required)

  How many stars in your universe?  The more the merrier.

XS=XSize, YS=YSize, ZS=ZSize: (Default=160)

  This is how large your sphere or rectangular starfield is.  Only
  XSize is needed, YSize and ZSize will be equal to XSize if they
  are left out.  This lets you produce a sphere or a galaxy like
  shape.  These valused are used to produce squares and rectangles
  by using the Cube switch described later.

SS=SmallStarSize, LS=LargeStarSize: (Default=5)

  How big are the stars?  If just SmallStarSize is given the stars
  will all be the same size.  If both Small and Large values are given
  the stars will be randomly sized between these two values.  This is
  the radius of the star.

RV=RadiusVolume: (Default=0, Max=100)

  When Cube is not set, stars are scattered across the surface of
  a sphere.  This sets the 'thickness' of the skin of stars.  A
  value of zero causes it to be perfictly thin, and a volume of
  100 will cause the sphere to be filled totally with stars.  As
  you increase thie value, stars start to fill in the sphere from
  the outside skin to the center point.
  XLogScale is ignored when this options is selected.

F=Faces:

  By default Stars generates a 4 sided 3D star.  This option makes stars
  stars out of flat disks instead.  Faces is the number of triangles used
  to make each disk.  The more used the smoother the star, but the more
  space it will take up.  Use a whole number above zero.  Using a one will
  give you single triangles, and two gives squares.  Higher numbers
  start to give the look of disks.  The stars are automaticly rotated
  to face the axis of the object.

LR=LowRed, HR=HighRed, LG=LowGreen, HG=HighGreen, LB=LowBlue, HB=HighBlue:
(Default= LowRGB: 230,235,250 HighRGB: 255,255,255)

  Each star can be randomly colored.  This sets the colors for
  the stars.  The colors are picked between the min and max
  values.  If you set the Highs to 255,255,100 and Lows to 0,0,0
  you will get a color range from black to yellow.

Seed: (Number)

  By default Star will seed the random number generator with the
  Amiga's clock to give diffrent starmaps for each program run.
  But sometimes you might want to render with the same seed.
  For example, render two starfields exactly the same except for
  the star sizes.  You could then have the star sizes change in
  an animation.  Or better, change the X,Y,ZSize from very
  small to very large.  Use states to make an explosion of stars.

XL=XLogScale, YL=YLogScale, ZL=ZLogScale: (Default=1)

  By default, a filled sphere or rectangle block will have stars filling
  it evenly from start to finish.  These paramaters let you change that
  to a more natural look, with the stars thining out at the edges.  For
  a rectangular block, all three paramaters can be given diffrent values
  to prodice the desired result.  For spherical starfields only the
  XLogScale value is used which modifies the radus of the sphere.  For a
  torus, the YLogScale is ignored.  Values staring with 2 and above turn
  on the Log effect.  The higher the number the more 'squeezed' the stars
  will become.

XT=XTarget, YT=YTarget, ZT=ZTarget: (Default=0)

  By default, stars are aligned with the objects center.  You can
  change this with these paramaters.  The stars will then be rotated
  so that they all face the point defined by the X,Y,Z values above.

P=PARTICLES: (Switch Deafult=OFF)

  Normally stars are made up of four sided objects.  This switch
  tells stars to make them out of a single triangle.  It also
  turns on Particles for this object, setting the Type to Sphere
  and Alignment to Faces.  This is useful for when you want to get a
  little closer to the stars or want to use a diffrent shape than
  the one Stars generates.  This produces the best looking stars
  in my opinion since CSG spheres will not have angles no matter
  how close you get to them.  NOTE!  Remember to use trace mode
  unless you set the particle type to something diffrent.  CSG
  spheres are made up of triangles in Scanline and it will eat all
  your memory if you use lots of CSG stars in Scanline.  In trace
  mode it is pretty memory efficent.  The Faces option is disabled
  when PARTICLES is activated.

NA=NOALIGN: (Switch Default=OFF)

  When using the PARTICLES or FACES switch, all triangles will be
  facing the objects axis.  This is so if the camera is in the
  center of the starfield it will see every disk or triangle face
  on.  This switch turns this feature off and draws the triangles
  facing in the same direction.

RA=RANDOMALIGN: (Switch Default=OFF)

  This will randomly spin each star instead of aligning to the target
  point or leaving every star facing in the same direction.

FD=FASTDRAW: (Switch Default=OFF)

  This simply sets the FastDraw button for the generated object in
  case you don't want to see all 10,000 stars draw when you first
  load it.

C=CUBE: (Switch Default=OFF)

  This forms the stars from a cube or rectangle instead of a sphere.
  This fills them in a volume defined by the XSize, YSize, and ZSize.

T=TORUS: (Switch Default=OFF)

  Torus is used when you want to create an asteroid field or any other
  tube like volume of stars.  When TORUS is switched on, an oval or
  rectangle with the dimentions of XSize by ZSize is swept around the
  Z axis with a rasius given by YSize.  Imagine defines a torus by a
  ring and tube radius.  In Stars, XSize and YSize define the tube
  radius, and YSize is the ring radius.  You should set RadiusVary to
  100 if you want a solid circular torus. Otherwise it is hollow.

   This is an example of using a rectangular based torus:
  Stars Ast.iob 1000 XS=50 ZS=40 YS=160 SS=0 LS=2 ZL=2000 XL=15 TORUS CUBE
   And a circular torus:
  Stars Ast.iob 1000 XS=75 ZS=25 YS=150 SS=0 LS=2 RadiusVary=100 TORUS

RA=RANDOMPOINTS: (Switch Default=OFF)

  The RandomPoints flag will place each stars point randomly. This works
  best with tetrahedrons and produces randomly shaped asteroids.  It also
  will work with Faces and Particles.  Using it with Faces will give a
  crumpled-paper look to each asteroid.

INFO: (Switch Default=OFF)

  INFO tells Stars not to write a file, but to simply tell you about
  the starfield that would be generated with the paramaters given.
  Just how much space does 10,000 stars take?

Ok.. to get an idea of what this looks like do the following...

 "Stars universe.iob 2500 XS=2000 SS=1 LS=25 PARTICLES"

Now load this object into the detail editor.  Your view should be inside
the sphere of stars.  Use "Reset View" if this is not the case.
Now render this in full trace mode in hires.  You should see a nice
starfield full of stars of differing size and brightness.  And better
yet, the stars will not dissapear when you render a 1280x800 project like
the Imagine ones do.  Imagine's stars are only a single pixel, so the
entire look of them changes when you change screen modes.  Not good.

For an interesting swarming effect make a project and copy the included
staging file into it.  Next go to the Ram Disk and make six starfields named
Stars0.iob to Stars5.iob with the command. "Stars <name> 20 XS=160 SS=75 NA"
Now make a preview looping anim in the Stage editor... since each starfield
is random it makes a pretty interesting scene for such a simple setup.
There are lots of possibilities here..  you could make the XSize 1 at the
start of the anim and 160 at the end to have the objects swarm outward
randomly. Let me know anything neat you do as well as any bugs and or
suggestions!  Feedback is nice.  :-)


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