ginstance

Class

Shape

Synopsis
A geometry instance primitive, i.e., a shape which is a replication of another, specified, shape node.
visibility

You can selectively disable an object's visibility for the various types of rays in the renderer. By default, objects are visible to all types of rays. Camera - Camera (AA) rays (i.e., primary or view rays). Shadow - Shadow rays fired in the direct lighting calculations. Specular - specular reflection rays. Transmission - Transmission rays. Diffuse - Indirect diffuse rays (i.e. global illumination or GI rays). Specular - Indirect specular rays (i.e. specular reflection rays).

sidedness

Just like you can disable the visibility for specific ray types, you can also change an object's sidedness depending on the ray type. By default, objects are double-sided for all rays. By unclicking any of these checkboxes, the object will become single-sided, which means that those parts of the object whose normal vector points away from the incoming ray direction will not be rendered.

receive_shadows

Determines whether or not the object picks up shadows from other objects.

self_shadows

Determines whether or not the object casts shadows on itself.


invert_normals

Invert normals (so that normals face inwards and not outwards).

ray_bias

Raytrace bias value specified for the object.

matrix

Transformation matrix. This can be either a single matrix or an array of matrices that define the SRT motion of the object for the current frame. (The matrices define the motion for the full frame, not just between the shutter open - close time.)

transform_type

Specifies what type of motion the object has. Options are linearrotate_about_center, and rotate_about_originlinear corresponds to the linear interpolation between matrices. rotate_about_origin corresponds to curved_motionblur=true. Unlike, rotate_about_origin which sets the rotation pivot at the origin, rotate_about_center will rotate about the object's center. This is the default mode and is useful for wheels, propellers, and other objects which spin.

shader

An array of nodes pointing to the shader or shaders in the case of per-face shader assignment.

opaque

The opaqueness (transparency) of the object. By default, all objects are marked as opaque, because that speeds up the rendering considerably. Note that this flag is not set automatically by adding a transparent material to the object, it has to be set manually!

matte

The matte option enables you to create holdout effects by rendering the alpha as zero.

use_light_group

A boolean to enable selective light linking

light_group

An array of nodes pointing to the lights that will affect the node if use_light_group is enabled.

use_shadow_group

A boolean to enable selective shadow linking.

shadow_group

An array of nodes pointing to the lights that will not cast shadows on the polymesh, if use_shadow_group is enabled.

trace_sets

An array of strings each of which names a trace set. A custom shader must be used to make an effective use of these strings via the AiShaderGlobalsSetTraceSet and the AiShaderGlobalsUnsetTraceSet API calls.

motion_start

The time at which the first motion key of the shape is sampled. Other motion keys must be uniformly spaced within this range. By convention, the times are frame relative. For example, start and end times -0.5 to 0.5 indicate that the motion keys were sampled midway between the previous and current frame, and the current frame and next frame. This is applied to cameras, lights, and shapes.

motion_end

The time at which the last motion key of the shape is sampled. Other motion keys must be uniformly spaced within this range. By convention, the times are frame relative. For example, start and end times -0.5 to 0.5 indicate that the motion keys were sampled midway between the previous and current frame, and the current frame and next frame. This is applied to cameras, lights, and shapes.

id

Unique ID for a node in the Arnold scene. 

node
Shape node to create an instance of.
inherit_xform
If enabled, the instance transform is combined with the original shape node transform. If disabled, the original shape node transform is ignored and replaced by the instance transform.
step_size

Sets the size for sampling inside the volume. It should be small enough to capture the smallest feature in the volume (aka the Nyquist limit). If the size is too large, aliasing, bias or banding will appear. Smaller (and therefore more accurate) sizes will increase render times while larger sizes will render more quickly. 

 

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