Houdini chains together operations into complex networks (bottom window) that can easily be manipulated, edited and packaged for portability in production pipelines.

Character Animation
While character animation is a core feature of other applications, Houdini has received relatively little attention for its character tools. In fact, Houdini offers a complete set of character set up and animation features, including powerful FK/IK controls and deformations. While character animation is not Houdini's calling, the tools are capable of producing character performances with subtle levels of detail. By themselves, the character animation features are probably not a compelling reason to invest in Houdini, but they do complete the pipeline for projects that need character work to go with their effects animation.

Modeling
Model building is probably the area that suffers most from Houdini's procedural workflow. While the software does have a reasonable set of Nurbs and polygonal modeling tools, modeling itself requires constant switching between many types of tools, snap settings, and tool variations, and pushing and pulling points and surface elements on various axes. This all implies a fast-and-loose workflow that is at odds with Houdini's add-a-SOP-manipulate-and-repeat methodology. Furthermore, Houdini's modeling toolkit is considerably smaller than those in competing products. Most significantly, Houdini lacks for subdivision surfaces as a model type, even though they have become the new standard in animation environments. (Side Effects does point out that you can render polygons as sub-d's in rendering.)

Effects
The one area where Houdini has made its greatest inroads and truly excels is in the creation of dynamic effects. Like Maya, and other high-end apps, Houdini has a robust set of rigid and soft body dynamics and particle effects. What sets Houdini apart in this realm is the easy of creating complex effects, thanks to the Ops workflow. While complex effects in Maya, for example, generally require heavy levels of scripting, effects in Houdini can often be achieved by simply adding operators where needed along the chain. There's nothing wrong with scripting per-se, but effects that rely heavily on scripting also rely heavily on TDs who can tear apart and rewrite scripts every time a change needs to take place in an effect. As in other parts of Houdini, changing what's already been done is relatively easy by comparison. Also, importantly, effects can be easily packaged and exported to other projects where they can be modified to meet the demands of the new scene.

Houdini comes ready to generate some sophisticated effects right out of the box. And, in particular, it offers powerful features for creating flocking behaviors and working with instanced geometry. Key to this is the capability to manipulate the forces between particles.

As with any effects system, greater degrees of complexity call for the direct application of math supplied by well-schooled TDs. Past versions of Houdini limited scripts to single-liners that could be placed within data. One of the appreciable changes in version 7 is a multi-line script editor that will remind many artists of Maya's Script Editor.

Houdini's effects system also incorporates a rich set of soft and rigid-body dynamics and good control over using scene geometry as both particle emitters and collision objects. Particle systems are able to preserve the momentum imparted by emission objects, another important aspect of creating compelling dynamic effects.