Houdini plugin - Extensions

Extensions are pieces of code which allow extend the capabilities of Maxwell Render. The built-in extensions are available in Houdini as OBJ or SOP nodes, and some of the standard Houdini nodes are translated as extensions to the Maxwell scene.

There are two types of extensions in Maxwell: 

  • Extension Objects: the extension code generates a new object in the scene with particular characteristics (like the Maxwell Sea, Volumetric or the Alembic importer).
  • Object Modifier Extensions: the extension modifies an existing geometric object (like the Grass, Scatter or Subdivision modifiers).

Extension objects

Extension objects can be found as OBJ nodes in Houdini.The following extensions are supported:

Maxwell Volumetric

The Maxwell Volumetric Houdini node supports different types of volumetric fields:

  • Particle Field: use a particle simulation to define the volumetric density. The particles can be loaded from external particle file in several formats (.abc, .bin, .pxy, .prt, .rpc) or from any Houdini geometry node. When a Houdini geometry node is selected the source, all points of the geometry is translated as particles, the channels such as density, force, velocity, etc. are expected as point attributes.
  • Constant Field: creates a cube shaped volumetric area with constant density. This is useful for very large atmospheric haze effects for example.
    • Noise 3D: also functions as the constant density type except it adds an adjustable 3D noise to create density variations in the volume.
  • Voxel Field: translates any Houdini geometry which contains volume primitives (such as Pyro FX nodes).
  • VDB: allows you to define an Open VDB file / sequence with volume information.

Read more...

Maxwell Sea

Maxwell Sea creates a simulation of the ocean surface based on the Ocean Statistical Spectrum solver (in RealFlow™), that produces a realistic waves simulation from a simple plane. Read more...

Maxwell Alembic Object

The Alembic scene format is an industry standard format developed by Sony Pictures Imageworks and Lucasfilm and released in 2011 that represents a very efficient way to store and reference geometry. Read more...

The plug-in also supports Houdini's alembic archive node and translates it to the Maxwell Alembic extension using the following mapping:

Houdini nodeMaxwell extension
File NameAlembic File
FrameFrame Number
Frames Per SecondFPS

 

Object Modifier Extensions

Object Modifier Extensions are located on the SOP level (except the Maxwell Grass nodes which is an OBJ). The following extensions are supported:

Hair and fur

Maxwell Render uses the MaxwellHair.mxx procedural primitive to be able to read fur and hair fibers and render them without the need to convert the fibers into triangles. Read more...

The plug-in translates Houdini's fur node to the Maxwell Scene using the MaxwellHair extension. The extension's extra parameters can be defined with detail or point geometry attributes in the fur. These extra parameters are:

NameClassTypeDescription
radiusPointfloatRadius of the hair points.
mbPointfloatMotion blur factor of the hair points.
colorPointvectorColor of the hair points.

Maxwell Grass

The MaxwellGrass extension allows you to create different types of grass very easily and quickly. Read more...

The Maxwell Grass node requires a geometry object which is the source of the grass. The geometry can have the following extra attributes defined:

NameClassTypeDescription
triangle_with_bladesPrimitiveintegerOptional array to define which triangles of the modified mesh will have blades.

Maxwell Subdivision Modifier

The Subdivision modifier implements Pixar OpenSubDiv subdivision modes to subdivide low-polygonal objects into smooth surfaces. Read more...

The plug-in also supports Houdini's subdivide node with the following mapping:

Houdini nodeMaxwell extension
DepthLevel
Crease Weight (if enabled)Edge Crease
 Type: Catmull-Clark
 Interpolation: Edges and Corners

Maxwell Scatter

The MaxwellScatter extension allows you to distribute instances of an object across the surface of another object randomly, while providing control over the random distribution. Read more...

The plug-in also supports Houdini's scatter node. It calculates the Density from the number of points and the surface area of the source geometry.

Maxwell Cloner

The MaxwellCloner extension allows you to to distribute thousands of instances of the same object using the distribution from a particle BIN file. Read more...

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