Turbulence Settings
Click on an area of the dialog to go to the appropriate
page
Mixture controls
The controls in the Mixture group control the visibile
nature of the turbulence applied to the basic flame shape that then produces the
final flame texture.
Octaves
The Octaves setting determines how turbulent the final
texture is. A setting of 0 (Zero) will diable the turbulence
altoghther - the result will be the underlying basic flame shape determined
from the Shape and Colour
controls.
Increasing values of Octaves will result in increasingly turbulent
textures, with more and more detail becoming evident in the flames. You will
reach a point, however, where increasing the Octaves will no longer produce
any more detail - this being determined by the resolution of the displayed
texture. This means two things:
- The material preview windows will normally stop displaying a change in
texture as you increase Octaves before the actual rendered texture will
(assuming the rendered texture is larger, in pixels, than the material
preview window).
- There is a point at which there is no point in increasing the Octaves
value, as you will only spend time calculating detail that cannot be
displayed at the resolution available - i.e. your renders will take longer
for no benefit.
X Scale
The X Scale setting determines the scale of the turbulence
in the horizontal direction of the texture, or, in other words, the size of
the features created by the disturbance creatred by the turbulence. Increasing
values of X Scale will create smaller sized features but in
increaing number.
Y Scale
The Y Scale setting determines the scale of the turbulence
in the vertical direction of the texture, or, in other words, the size of the
features created by the disturbance creatred by the turbulence. Increasing
values of Y Scale will create smaller sized features but in
increaing number.
Seed controls
The turbulence produced is based on a psuedo-random number sequence. What
psuedo-random means is that, whilst the sequence appears random, it is in fact
predictable and repeatable. This has its good points and its bad points.
One of the good points is that the resultant texture is repeatable, i.e. with
a given set of parameters you will always end up with the same image/s. This
becomes important if you try to do advanced things like animate lights in
sequence with the shape of the flame texture to imitate the flickering of
firelight.
The bad thing is, every flame you create in your scene would end up looking
exactly the same shape and move in exactly the same way. This looks very bad, as
the human eye-brain combination is very good at recognising patterns - both
static and synchronised movement. This is where the seed controls come in. The Seed
determines where in the psuedo-random sequence the texture generator should
start generating numbers. By setting the starting point at a different location
for each flame in the scene, the resulant flame images are typically very
different in shape and movement. If you do happen to end up with two flames
looking too similar simply change the seed value for one of them.
Seed
The current Seed value is displayed and can be manually
edited in this field.
Randomise
The Randomise button simply saves you trouble of thinking
up a random seed value and typing it into the Seed edit
control. It generates a random seed value for you with the click of a button.
