Houdini plugin - Extensions
- Peter Horvath (Unlicensed)
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.
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 node | Maxwell extension |
|---|---|
| File Name | Alembic File |
| Frame | Frame Number |
| Frames Per Second | FPS |
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:
| Name | Class | Type | Description |
|---|---|---|---|
| radius | Point | float | Radius of the hair points. |
| mb | Point | float | Motion blur factor of the hair points. |
| color | Point | vector | Color 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:
| Name | Class | Type | Description |
|---|---|---|---|
| triangle_with_blades | Primitive | integer | Optional 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 node | Maxwell extension |
|---|---|
| Depth | Level |
| 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...