Houdini 17.5 What’s new What was new in Houdini 16

What was new in Finite elements and cloth

On this page

Finite elements


Solid Conform SOP replaces Tetrahedralize SOP for most use cases. This node tolerates intersections and holes in the mesh.


Solid Conform option to make tetrahedron orientation match source polygons exactly (useful in some situations, such as matching a locked-down render model, or if you need manual control of tet layout).


Solid Embed SOP is a high-level node designed for use in embedded FEM simulations.


Hybrid Object: finite element interior within a separately-solved polygonal skin, allowing uneven distribution of content within the container, and wrinkling/bunching of the container skin.

  • On the Solid Conform node, turn on Add surface triangles.

  • Isotropic skin model for the surface polygons.

  • Used extensively in Houdini’s new muscle system.


Solid Object 2.0.

  • Shelf tool now does a solid embed, so the original hi-res object is animated based on the simulation of a low-res tet mesh.

  • The default physical properties are now soft instead of hard/brittle. Feedback from customers showed most people are using solid simulations for soft objects.

  • Initialize behavior menu has physically realistic presets for rubber, organic tissue, and cork.

  • Stiffness multiplier parameter keeps values in stiffness parameters at reasonable scales for editing (for example, 33.557 instead of 33557000).


TetPartition partitions existing tetrahedral geometry based on a polygon mesh. For example, connect a tetrahedralized wall to the first input and a polygon mesh enclosing regions that you want to be solid on the second, and Tet partition adds a primitive attribute assigning a unique number to each enclosed region.


New system of point attributes allow you to scale material properties per-point. This lets you, for example, paint an attribute to make the ears of an animal extra floppy.

  • Attributes have the same name as a corresponding parameter on the Solid Object or Hybrid Object nodes.

  • You can use the point attributes to create differently-behaving "sub-objects" within a single Solid Object or Hybrid Object (as the muscle system does).


Finite Element solver:

  • Simplified options for greater stability.

  • New integrator type: ABE2 integrator retains more energy, more lively, keeps moving longer. (The look of the two integrator types will converge as you increase substeps so they both get closer to reality.)

  • Improved soft body solving.

  • Collision solver now faster and more robust.

  • Separate collision controls for the interior side and the exterior side of each collision surface (available on both regular and hybrid solids).


New default Max radius/edge ratio parameter prevents tetrahedralization from filling the interior with large elements.


Redesigned FEM constraint system. In particular, the soft constraints are much easier to control and can follow a target animation more closely. You can also use the improved soft constraints for secondary wrinkling sims, where the wrinkles are simulated after the primary sim.


Tetrahedralize SOP now has a simpler interface for more robust tetrahedralization. This node is still low level but can be used reliably to create convex hulls and refine existing tetrahedralizations. It also contains troubleshooting tools to help resolve problems.

The convex hull functionality is available through a new Convex Hull shelf tool.


Native support for collision with height fields.


Finite elements and the Solid Object node’s preset menu now respect the HIP file units.



Cloth Object 2.0:

  • Easier to use parameters.

  • New thickness control for simulating thick material such as felt. This gives the equivalent of simulating a layer of tets, but avoids the associated overhead. (Use "Strong" bend model for thick materials.)

  • Initialize behavior menu has physically realistic presets for chiffon, silk, cotton, and more.


New Cloth Solver with specialized interface and defaults for cloth, separate from the Finite Element solver.

What was new in Houdini 16