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The normal Light node starts with a large number of commonly used render properties. If you want to build a completely customized light with only your choice of render properties, you can use this node as a starting point instead of stripping down the regular light node.
If you just want a standard light object, use the normal Light node instead.
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.
Translation along XYZ axes.
Degrees rotation about XYZ axes.
Local origin of the object. See also setting the pivot point .
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.
This reverts the translate, rotate, scale parameters to their default values while maintaining the same overall transform.
This sets the translate parameter to (0, 0, 0) while maintaining the same overall transform.
This sets the rotate parameter to (0, 0, 0) while maintaining the same overall transform.
This sets the scale parameter to (1, 1, 1) while maintaining the same overall 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.
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.
When the object is being transformed, maintain the current world transforms of its children by changing their transform parameters.
Enable Constraints Network on the object.
Path to a CHOP Constraints Network. See also creating constraints.
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.
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.
Viewport Selecting Enabled
Object is capable of being picked in the viewport.
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.
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.
This variable is deprecated. Use the instancepoint expression function instead.
The following examples include this node.
This example demonstrates how to use the Dynamics CHOP to extract impact data from a DOPs simulation, and then modify the data to control lights in the scene.
This example uses the Hold CHOP in conjunction with the Dynamics CHOP to hold a light at the position of an impact from a DOPs simulation until a new impact occurs.
This file demonstrates the Object CHOP.
The CHOP is used to bring in the channel information from a Object.
This data can then be manipulated within CHOPs and exported back into the Object, or even a different Operator.
The Box SOP is used for more than just creating boxes. It can also envelop existing geometry for specific purposes.
The Box SOP can either create a simple six-sided polygon box, calculate the bounding box size for geometry, or be used in conjunction with the Lattice SOP.
There are two objects within the box.hip file that are examples of this:
The animated_bounding_box object shows how you can envelope an object and surround it with a simple box, even if it is animated. This can be useful when displaying complicated geometry, in which case you would put the display flag on the box object and the render flag on the complicated geometry.
This is an example, a Lattice SOP used in conjunction with the Box SOP. The Box SOP is used to envelope some geometry, in this case a sphere. Divisions is checked to create the proper geometry by referencing the number of divisions in the Lattice SOP.
The top points of the box are grouped by a Group SOP. The Spring SOP uses these points as the Fixed Points from which to create the deformation.
Using the Box SOP in this way allows you to change the incoming geometry (the basic_sphere in this case) and have the box and lattice automatically re-size for you.
This example demonstrates how to have multiple shading layers with different uv sets using the Layer SOP and the VEX Layered Surface SHOP.
This example shows the ability of the Particle SOP to define a default Size for any given birthed particle.
A simple Grid can be used to create a dynamic solution of particles streaming off as if blown by the wind. As these particles leave the grid, their size slowly diminishes, as the particle continues to die.
The Ray SOP projects one object over the surface contours of another.
It does so by calculating the collisions of the projected object’s normals with the surface geometry of the collided object.
In this example, a Grid is wrapped over the surface of a deformed Sphere using the Ray SOP.
A Facet SOP is used to correct the normals of the wrapped Grid after it is deformed over the surface.
The Rest Position SOP creates an attribute based on the surface normals that allows a shader to stick to a deforming surface.
All primitives support the rest attribute, but, in the case of quadric primitives (circle, tube, sphere and metaball primitives), the rest position is only translational. This means that rest normals will not work correctly for these primitive types either.
Use the Rest Position SOP only when you are deforming your geometry and you are assigning volumetric or solid materials/patterns in your shader.
Rest normals are required if feathering is used on polygons and meshes in Mantra. NURBs/Beziers will use the rest position to compute the correct resting normals.
It will be necessary to render the setup in order to see the effect.