Deborah R. Fowler
Fluids - Pyro Tips
Posted: 2013
Updated: Aug 16 2024
Remember in simulations scale is important. (The defaults are in meters, kg, seconds - as seen in the Preferences/Hip File Options)
See also
TIPS:
- Animate
your source - adds some variety to your
simulation (can be as simple as adding a mountain node
with a time value in the offset parameter). Just as you
should do with a liquid fluid.
- The shelf tool does this in the pyro presets - for example in a billowy smoke "attribadjustvector_velocity" is set to animate noise
- Adding a attribute noise after your pyrosource can be used, select your attribute names and then click the checkbox on the node for animate
- Add or manipulate data as necessary - Scott Keating's Volcano tutorial (2012) has an excellent, widely applicable example of this where he modifies the wind velocity to influence the pyro smoke plume. Although this tutorial is for an older version of Houdini, the technique is still widely used - manipulating data fields.MA
Two aspects to pyro are simulation (shape) and render
(shader):
- Light your effect - light can shape the look of your smoke/flames - pay attention to the lighting as well as the shader
- Use Background color for CONTEXT - always keep in mind what background you will be compositing onto - things look denser/fuller on dark backgrounds
- Voxel resolution - the lower the number, the more
details - the longer the sim. The resolution is key to the look.
(This number depends on the size of your simulation ie. values
.04 to .07 can give good results, lower will be more detailed,
however will increase sim time but may work just fine for
smaller effects. If you can afford the sim times lower it, but
be sure to check more than the first few frames.)
- Two sites that provide a visual catalog of values for parameters are
- comparisons and explanations of parameters by Vladimir Abramov here
- Christopher Chamberlain here
- KARMA - now in 20.5 has a Karma pyro material in the material
library, similar to mantra, there is now a material properties
where volume step rate can be set in the material
- MANTRA Pay attention to the render settings: (see
Mantra Sampling parameters)
- Volume Quality
- Volume Step Rate - vm_volumesteprate was renamed in a late build of 16.0 and vm_volumequality was introduced in 16.5 according to the forum post here
