Houdini plugin - Camera and object parameters

Owned by
Peter Horvath (Unlicensed)
Last updated: 18 Nov, 2012Version comment
3 min read

Camera

Each camera node defined in the scene and marked as rendered will be translated to Maxwell Render by the plug-in, same way as the other renderers (like Mantra) work.

Basic camera parameters such as shutter speed, f-stop or position, rotation, uv coordinates are read from the Houdini camera node itself (see the Maxwell Camera (OBJ) chapter). In addition Maxwell has some specific parameters which are not available on Houdini’s default camera node. These can be defined with the Maxwell Camera Params node on the OBJ level which expects the camera node as the input.

 

Maxwell Render simulates a real camera with the associated lens set, diaphragm, etc. parameters. Special camera parameters are the following:
  • Use Shutter Speed: camera shutter is different in Houdini and Maxwell. Houdini stores shutter time in 0 – 1 interval, while Maxwell uses shutter speed. Shutter time is translated with a formula (described in the Maxwell Camera section) which has some limitations. If this flag is turned on, the given value will be used as the camera shutter speed in the Maxwell scene.
  • ISO: specifies the film's light- sensitivity. Higher ISO is more sensitive.
  • Aperture: controls the shape of the “bokeh” effect caused by bright spots in the parts of the render that are out of focus. (Circular or Polygonal)
  • Blades: specifies the number of blades for Polygonal diaphragm.
  • Angle: specifies rotation angle of aperture opening for Polygonal diaphragm.
  • Shift Offset: specifies the offset of the lens position horizontally and vertically which can be useful to correct geometric perspective distortion.
  • Custom Bokeh: enables anamorphic bokeh, allowing you to get a natural anisotropic non-round bokeh.
  • Bokeh Ratio: specifies the aspect ratio of the anamorphic bokeh.
  • Bokeh Angle: specifies the angle of the anamorphic bokeh.

Object

Each geometry node defined in the scene and marked as rendered will be translated to Maxwell Render by the plug-in, same way as the other renderers (like Mantra) work.

Basic geometry parameters such as position, rotation, uv coordinates are read from the node, but Maxwell objects has some specific parameters which are not available on Houdini’s default geometry node. These can be defined with the Maxwell Object Params node on the OBJ level which expects the geometry node as the input.

 

Maxwell related object settings are the following:

  • Object ID: specifies the color to identify the object.
  • Subdivision Level: specifies the subdivision level of the mesh.
  • Recalculate Normals: calculates normal vectors for each face when the geometry is translated to Maxwell Render. When this flag is turned off then the plug-in tries to find and use the normal point attribute associated with the geometry. When no normal point attribute is set, gives a warning and recalculates the normals.
  • Smoothing: this flag can be set when recalculate normals is turned on. Smoothing means that point normals will be calculated to the geometry instead of face normals which guarantees continuous surface in the render. Smoothing is turned on by default.
  • Hidden From Camera: specifies the visibility of the object.
  • Hidden From Reflections/Refractions: reflected or refracted objects are hidden.
  • Hidden From Global Illumination: the object will render but will not affect lighting.
  • Hidden From Z-clip Planes: if this option is selected, the object won't be cut by Z-clip planes.