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Instance Objects can instance other geometry, light, or even subnetworks of objects. By enabling point instancing, the point geometry of the instance object is used to create multiple instances, similar to the copy SOP.
Parameters ¶
Transform ¶
Transform Order
The left menu chooses the order in which transforms are applied (for example, scale, then rotate, then translate). This can change the position and orientation of the object, in the same way that going a block and turning east takes you to a different place than turning east and then going a block.
The right menu chooses the order in which to rotate around the X, Y, and Z axes. Certain orders can make character joint transforms easier to use, depending on the character.
Translate
Translation along XYZ axes.
Rotate
Degrees rotation about XYZ axes.
Scale
Non-uniform scaling about XYZ axes.
Pivot
Local origin of the object. See also setting the pivot point .
Uniform Scale
Scale the object uniformly along all three axes.
Pivot
Local origin of the object. See also setting the pivot point .
Modify Pre-Transform
This menu contains options for manipulating the pre-transform values. The pre-transform is an internal transform that is applied prior to the regular transform parameters. This allows you to change the frame of reference for the translate, rotate, scale parameter values below without changing the overall transform.
Clean Transform
This reverts the translate, rotate, scale parameters to their default values while maintaining the same overall transform.
Clean Translates
This sets the translate parameter to (0, 0, 0) while maintaining the same overall transform.
Clean Rotates
This sets the rotate parameter to (0, 0, 0) while maintaining the same overall transform.
Clean Scales
This sets the scale parameter to (1, 1, 1) while maintaining the same overall transform.
Extract Pre-transform
This removes the pre-transform by setting the translate, rotate, and scale parameters in order to maintain the same overall transform. Note that if there were shears in the pre-transform, it can not be completely removed.
Reset Pre-transform
This completely removes the pre-transform without changing any parameters. This will change the overall transform of the object if there are any non-default values in the translate, rotate, and scale parameters.
Keep Position When Parenting
When the object is re-parented, maintain its current world position by changing the object’s transform parameters.
Child Compensation
When the object is being transformed, maintain the current world transforms of its children by changing their transform parameters.
Enable Constraints
Enable Constraints Network on the object.
Constraints
Path to a CHOP Constraints Network.
Tip
You can you use the Constraints drop down button to activate one of the Constraints Shelf Tool. If you do so, the first pick session is filled automatically by nodes selected in the parameter panel.
Note
Lookat and Follow Path parameters on object nodes are deprecated in favor of Look At and Follow Path constraints. The parameters are only hidden for now and you can set their visibility if you do edit the node’s parameter interface.
Viewing Options ¶
Set Wireframe Color
Use the specified wireframe color
Wireframe Color
The display color of the object
Viewport Selecting Enabled
Object is capable of being picked in the viewport.
Select Script
Script to run when the object is picked in the viewport. See select scripts .
Cache Object Transform
Caches object transforms once Houdini calculates them. This is especially useful for objects whose world space position is expensive to calculate (such as Sticky objects), and objects at the end of long parenting chains (such as Bones). This option is turned on by default for Sticky and Bone objects.
See the OBJ Caching section of the Houdini Preferences window for how to control the size of the object transform cache.
Shade Open Curves In Viewport
Any open curves contained in this object will be lit when the viewport is set to do so.
Turning this on will also use a GLSL shader better suited to hair if the whitehair
or guardhair
attributes are found in the geometry.
Curves with the width
attribute will also be rendered as thick ribbons with varying width in shaded modes.
Instance ¶
Display
Whether or not this object is displayed in the viewport and rendered. Turn on the checkbox to have Houdini use this parameter, then set the value to 0 to hide the object in the viewport and not render it, or 1 to show and render the object. If the checkbox is off, Houdini ignores the value.
Instance Object
Instance the given object’s geometry.
Point Instancing
Off
No point instancing. Instead, the instanced object simply replaces the instancing object.
Full point instancing
Lets you modify any object-level rendering property (material assignment, shading, sampling, dicing, etc.) across point instances via an expression, using the instancepoint()
function to get the current point index. It also supports the same point attributes as fast point instancing. The variation is done at export time, and usually leads to much larger IFDs/RIBs and slower export.
Fast point instancing
Renderable properties can only be varied across different point instances through a limited set of point attributes:instance
, material_override
, and shop_materialpath
. The last two can be easily set by using the Material SOP. Additionally, the object-level variations are ignored. For example, the instancepoint()
function will return zero. The variation is done at render time and has very little impact on the IFD size or export time.
Point Motion Blur
If point instancing, this parameter specifies the motion blur behavior when rendering. Each point will have an instance of geometry. The transform of this instance is determined by the point’s position. Transformation motion blur on the instance is determined by the motion of the point. The motion of the points is controlled by this parameter.
No Motion Blur
Do not perform motion blur.
Compute sub-frame geometry (deformation)
Compute the point’s position by evaluating the geometry at sub-frame intervals. This can be problematic if the point count is changing frame to frame.
Use point velocity attribute
The point’s vector attribute “v” is used to extrapolate the motion of the point.
Subnetwork Filtering
This option specifies how instancing is performed when a Subnet Object is specified as the Instance Object.
All Objects
Instance all objects within the subnet.
Displayed Objects
Only instance the displayed objects from the subnet.
Specify by a pattern
Use the pattern mask specified by the Subnetwork Pattern parameter.
Subnetwork Pattern
When Subnetwork Filtering is set to “Specify by a pattern”, this parameter gives the pattern mask for determining which objects are rendered from the instanced Subnet object.
Override Properties
Specifies a Property SHOP that is used to resolve rendering parameter values. At render time, this SHOP (if given) is used to resolve rendering parameter values first, before looking for them on the objects being instanced.
Note
It is also possible to attach a material to each point using the Material SOP.
Locals ¶
IPT
This is typically -1. However, if the object is performing point instancing, then this variable will be set to the point number of the template geometry. For the IPT variable to be active, the Point Instancing parameter must be turned on in this object.
Note
This variable is deprecated. Use the instancepoint expression function instead.