User Guide
12 REFERENCE
PYROCLUSTER
Render Mode
Here you can choose from various preset render modes. The main differences between
these modes are their render quality and how long they take to render. In order of
best render quality (and longest render time) rst, these are:
• Crispy
• Crispy-Gas
• Hazy
The following mode:
• User
allows you to set your own render mode using various parameters that will no longer
be ghosted including World Step Size and Ray Trans Limit.
Step Size settings
The Step Size settings are available only when Render Mode is set to User.
See also ‘How are PyroCluster effects created?’ earlier in this chapter.
To improve rendering time for volumetric PyroCluster effects you should set the step
sizes to reasonable values.
What is a reasonable step size? This question leads us to a problem that is common
to all volumetric fractals (a smoke cloud is a really large 3D fractal) – which is that you
can never tell in advance exactly how they will look when rendered. Many parameters
depend on each other and different combinations can have a dramatic impact on the
look and the render time of the nal effect.
The step sizes control how accurately the 3D space is sliced to nd PyroCluster volumes
(puffs) in the scene. As a rule of thumb, lower values (more slices) will usually result
in longer rendering times. If you feel that your scene is taking too long to render, try
adjusting these values rst.
Suppose you’ve created a scene with some clouds in the sky. You have chosen really
large volumes to create the 3D clouds (i.e. a large Radius value on the Shape page
for the PyroCluster shader). Each single puff has a radius of 2000.
If you leave the World Step Size at the default value of 0.5 you will wait forever to
nish rendering the scene, as too many samples are taken over the large volume.
In this case you could increase the step size values up to 60 without sacricing the
render quality.
If, on the other hand, you choose a small Radius value, say 10, and you still use step
sizes of 60 the render will be ugly, with single-color spheres only. This is because,
with a step size of 60, nearly all the small PyroCluster volumes would be missed in
the render. It will render very quickly, though!