[Figure 1] Users get FBX support with Houdini 9.1. Above is an FBX import dialog box (left). [Figure 2] Houdini 9.1 offers some new fluid tools in the Fluids shelf (right). All images courtesy of Anupam Das. 

When it comes to crafting complex visual effects, Houdini from Side Effects ranks among the top choices. This has been attributed primarily to its flexibility and powerful procedural node based approach to problem solving. Houdini 9.1 brings with it many improvements. Most notable are support for FBX, additions to the Fluids tools, faster dynamics and animation, a number of animation tool improvements, including better muscle control, and a number of great new set of shaders to add to its rendering toolset.

Let's look at a few of these improvements in depth.

FBX Support
Having used Houdini in production pipelines, it occurs to me that most studios that use Houdini are most definitely using some other software package in conjunction. Establishing a pipeline between Houdini and a second application has always been a challenge for me. A lot of users have been asking for FBX support in Houdini and their wait is now over.

Currently the FBX importer supports the following data:

• General: Meshes Triangulated Nurbs, Lights, Cameras, Joints and Bones.
  
• Attributes: User attributes, UVs, Normals.
  
• Animation: Translate, rotate, scale, vertex caches.
  
• Currently unsupported: Materials and textures, Native Nurbs, Skinning.

I proceeded to test the features with small and large scenes and it does work as advertised. This is great as it really streamlines my Maya-Houdini workflow and expands the scope of data I can export from Maya. I especially like the generic user attribute support, as I can add any number of complex attributes to my Maya particles and utilize them in Houdini to drive other effects. Houdini cannot presently export to FBX but I have heard that Side Effects is working on adding FBX export functionality soon.

Dynamics
There are some new fluids tools in the Fluids shelf. First, there is an Emit Particle Fluid button, which allows you to drop in a particle fluid emitter and sets everything up for you. It will create a default emitter, or specify any object shape for the emitter. You can place multiple fluid emitters and the fluids will interact with each other.

The new particle fluid sink tool kills any fluid particle that enters a volume. The volume can be a box, sphere, object or metaball. Very useful for controlling those troublesome stray particles.

Improvements have also been made to the particle fluids surfacing options. You can now stretch a surface along the velocity of the particle. Optimizations have additionally been made to the particle surfacing, which is now 60 times faster. Cloth simulations are now threaded so that has also resulted in significant simulation time improvements. I have noticed this especially with cloth/rigid body interactions.

Character Tools
Improvements have also been made to the character side of Houdini. Muscles now have handles, which you can use to interactively shape the muscle. There are five manipulators along a muscle that you can move squash-and-stretch. This allows you to shape the muscle in any desired shape. I found this to be very easy and interactive.