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realtrees.txt
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REAL 3D 2.49
FRACTAL TREE CREATION GUIDE
by Cy Starkman
Depth (Height, how many segments)
Init: 1-10
How many segments deep the tree will be. Each segment
will branch x times. This value determines the height or spread
of the tree. See Fig1
Rand: 0-100%
Affects the init value in a random way, therefore giving
branches an irregular length. While this is random you can set
limitations to ensure that your tree looks good.
0 - No effect
50 - Any branch may vary in total height by 25%
100 - Any branch may vary in total height by 50%
eg - With an init value of 4 and a rand of 50 any branch may
contain 3,4 or 5 height segments. With a rand of 100 any branch
might contain 2,3,4,5,6 height segments (but no less or more)
Branch: 0-100
A pair of digital clippers that force the branching to occur in
a specific pattern. Useful with leaves perhaps. See Fig2 for
visual explanation (much easier). NB: Leaves only appear at
when a branch ends. Good Vary range 30-70.
Branch(Bushiness, how many times does a segment branch)
Init: 2-10
How many branches the tree can have, also how many times each
segment can branch. The higher this the bushier the tree can
be, the lower the sparser. Fig3 (2 makes great fan coral)
Rand: 0-100%
Affect init in a random way. Creating segments with possibly
more or less branches. Limited use in that it also affects the
initial amount of branches. You want 3 main branches and you get
2 (not very nice)
0 - no effect
50 - any segment may have 25% more or less branches
100 - any segment may have 50% more or less branches
Depth: 0-100
Supposedly makes trees with less branches around the canopy
than in the centre. I am dubious whether this works or not. And
in any case I am not aware of many trees that behave this way.
Branch: 0-100%
The digital clippers again, this time it is for thinning your
tree out. Gives you a percentage of the maximum possible
branches.
0 - very sparse
50 - 50% of branches or sparse
100 - All branches possible are present - Very bushy
Size (Segment Diameter)
Depth: 0-100%
By what percentage is one segment thinner than the last. If you
make this number to little or create an inital size that is
small it is very possible that many of the branches will be
invisible or near invisible in renders. (it might be .005 wide)
Rand: 0-100
Randomly modifies diameter percentage
Branch: 0-100
Questionable use. It allows branches to get thicker or to stay
an equal thickness.
Length (Segment Length)
Depth: 0-100%
By what percentage is one segment shorter than the last. Once
again caution on how small this number is. If a segment is
getting 50% shorter each time your palatial Fig tree is going
to look rather stunted.
Rand: 0-100
Randomly affect segment length, use sparingly to give a less
'generated' look. NB: It is better to use the Height controls
to affect overall length.
Branch: 0-100
Questionable use. Possible uses if there are trees with
branches that have longer segments further out (I suppose there
are such trees).
Direction (Tightness)
Hor: 0-100 Fig4
From above Real3D trees spiral, this gives them a full
appearance. This value determines how tight or loose a spiral is
created. Lemon trees would have tighter spirals than Willow
trees.
Vert: 0-100
Fanning. Best shown in a tree with 0 Horz. the higher the value
the greater the fan. Fig5 shows a tree created in the front
view but viewed from the side view with 0 Horz and varying Vert
NB: Similar values create more balanced trees
Norm: 0-100
Acts as a limiter when applying gravity. The branches will bow
but not insanely (well). Defines a what is normal for the tree.
Having separate norms for horizontal and vertical would be
better.
Rand: 0-100
Same as all other Rand functions
Gravity: 0-100%
Upward or downward bowing of branches by x percentage of the
length of the segment being bowed. Upward or downward is
defined by the normal slider. Extreme use of this can cause
objects which look more like a weird hairdo then any tree.
As a guide values of 5-25 look normal
Rotate
Depth: 0-100
Causes branches to either bow down (willow) or up (apple?)
large scale gravity will cause this to limited success as such.
0 - no effect
50 - maximum downward bow
100 - maximum upward bow
See Fig 6
Rand: 0-100
Same as all other Rand functions some will some won't
Subdivision: 1-50
1 is good for test trees. Is great for finished trees, 50 well
a bit over the top perhaps. This value not only makes trees
smoother but also more defined. eg: the branches have more
subtle bends and kinks just like a real one!
Gadgets
Trunk:
Makes all branches sprout from the top of a trunk the height
you first define.
Central: See Fig 7
Alters the way branches get created. In effect gives even more
bushiness.
Branch & Leaf Color:
Eval definable equations for determining branch and leaf color.
A tree which starts off with a red trunk that becomes bright
yellow out at the branch tips. You got it! Or a basic variation
of leaf color.
Color will otherwise be taken from your current color (for
branches) and the object color (for leaves)
Creation Notes:
1) Your leaf object is created before going into the requester
and is the currently selected object. (Be careful when trying
different tree designs not to leave the last tree created
selected, trees as leaves gets pretty heavy). Unless specified
in the requester leaf color is that of your selected object/s
2) Leaves are positioned via their COG
3) Create trees in the front or side view (top view creates
sideways trees)
4) When defining primitives after leaving the requester you
first give the diameter of the first segment (or trunk) with a
primitive sphere. Then you define the starting position, length
of and angle of the first segment (or trunk) with a axis
primitive.
5) Think about diameter versus length when creating these two
objects else many squat fat trees will ensue.
6) Think about the diameter after it has been reduced 5 times
for the outer limbs. It is easy to make near invisible
branches.
7) Try many variations (But random is just that, you should be
able to create any tree without much random)
Limitations:
Leaves are a sore point, no banana trees, palms etc. You can
make the branches of anything. But leaves just stick on the end
of branches with little control.
No skeleton creation for limbs (Well it could be useful)
Depending on how you have defined your tree the leaves might be
sticking out at very strange angles. No easy avoidables that I
can find.
What is also needed:
Tree definitions from Fibonacci (An italian botanist) books. x
hundred years ago he personally measured the angles, lengths
and all information and how it relates for a lot of trees,
palms etc. I am told that SoftImage Tree creator is based on
his findings. His books should be in any state library.
Enjoy your trees.......