RealFlow Wisdom

RealFlow blog: Tips, Technics and Scripting.

Filter Daemon… ¡that Great Unknown!

This is one of my prefered utilities, the Filter Daemon. You can use it to kill, separate or split particles into more, it is a really cool tool. The best of this daemon is it saves time in scripting similar tools and computation time, because it is built as other multithreaded daemon in the core of RF. I´ve used it in this example to fake a melt effect.

This video shows the filter evaluating the position in Y axis.

In this example is being evaluated  pressures.

You can download the scenes from UpDown and Pressure.

Advertisements

July 24, 2010 Posted by | Daemons, Expressions, Particle Base Fluids, Tips | , , , | 16 Comments

How to animate emitter attributes in RFRK2.0?

Some features in RF5 are not available directly in RFRK 2.0, one of them is the possibility to animate the radius or splash, those which are included in the sequence tab:

To animate the particles attributes you have to do it manually, I mean using a simple mel line. First go to the frame you want to animate and set the value, then write in the Script Editor:

setKeyframe “rfrk_geo_flowmesher21.files[0].radius”;

Where files[0] is the first emitter in the tab list and radius is the attribute to set the key.

This video shows four particles with an animation in both Radius and Plygone Size attributes.

Note: Thanks to Mihnea Balta for the tip.

June 8, 2010 Posted by | RenderKit, Tips | , , , , , , | 2 Comments

How to create swell using expresions?

In scenes where you need to simulate shore waves, crest waves or simply breaking waves against the coast or cliffs, it is very useful the use of expressions. Expressions can be added to the  most node attributes  in RealFlow, using them to add cadence of movement or variability.

Imagine we are trying to simulate the coast where waves break against the rocks. You need to move the water or create a similar ocean movement.  Have a look to next video for better understanding of what I mean.

  In this set up I used an expression to control the cadence of the waves.

Maths are not my forte, 🙂 sorry,  so I´ll try to explain how works the expression I´ve used:

Given the expression

a*(1-sqrt(tanh(b*(sin(t/c)^2))))

where:

a was the Force Amplitude that will give the Wave Height

b was the sharpness of the pulse

c was the frequency of the pulse that will produce the Wavelength

This give you a force that produce a wave with a natural cadence. This is not a physically correct formula, if you want to know more about oceans have a look to internet, is full of articles about this field, these ar some of them:

http://www.boatsafe.com/nauticalknowhow/waves.htm

http://hyperphysics.phy-astr.gsu.edu/hbase/waves/watwav2.html

http://en.wikipedia.org/wiki/Wind_wave

February 8, 2010 Posted by | Animaton | , , | 4 Comments