Associated Parameters: GenerateSampleSetNode
Introduced
7.0
UI Location
• Geometry Queries
Description
Generates a data set of evenly distributed random locations on the input geometry. You can use the associated parameters to control a number of factors, including the size of the data set ("pointratetype"), how to interpret the Rate value ("ratetype"--see the description for the Rate port), and the type of point distribution ("emissiontype"):
- Surface: generates the locations on the surface evenly.
- Point: generates the locations only on the geometry points.
- Volume: generates the locations evenly inside the volume defined by the geometry.
When the Time Varying option is on, the generated set will change from one frame to the next.
In addition, you can also narrow from where the locations on polygon mesh geometries will be emitted by using the Filter attribute. If the emission type is set to "Surface", you can specify a portion of the surface; if the emission type is set to "Point", you can specify the points.
The syntax of this filter is the same as that of the GetDataNode when you use it to evaluate attributes at some locations. The current types supported for the attribute are: boolean, integer and scalar.
Integer and scalar values are clamped to a minimum of 0 and a maximum of 1. A value of 0 (or false for boolean) means the corresponding vertex or triangle is discarded from the set for the emission. Scalar values between 0 and 1 are used as weights when the emission type is set to Surface: a triangle will emit N% of the locations it would normally emit where N is equal to the weight of the triangle multiply by 100.
The current attribute contexts supported when emitting from a surface are:
- vertex: in the case of surface emission the weight of a triangle is the average of the weights of its three vertices.
- polygon: in the case of surface emission the weight of a triangle is the value of the attribute at the center of the triangle.
- polynode: in the case of surface emission the weight of a triangle is the average of the weights of its three polynodes.
There are two more parameters that can be used with the Filter attribute:
- Invert ("invertfilter"): when this parameter is set the actual filter will be 1 - the value of the attribute.
- Rate Control ("ratecontrol"): controls how the Rate will be applied (see the description for the Rate port below).
Parameters
|
Parameter Name |
Scripting Name |
Type |
Description |
|
Emission Type |
emissiontype |
Integer |
Possible Values: • 0: Point • 1: Surface • 2: Volume |
|
Rate Type |
ratetype |
Integer |
Possible Values: • 0: Number per Second • 1: Density per Second • 2: Number per Frame |
|
Point Rate Type |
pointratetype |
Integer |
Possible Values: • 0: Number per Second • 1: Number per Frame • 2: All Points |
|
Max Number |
maxnumber |
Integer |
|
|
Enable Max Number |
enablemaxnumber |
Bool |
|
|
Reference |
reference |
String |
Full Name |
|
Invert |
invertfilter |
Bool |
|
|
Rate Control |
ratecontrol |
Integer |
How the rate is interpreted when a filter attribute is specified Possible Values: • 0: Exact Rate • 1: Proportional to Filtered Area |
Port Description
Inputs
|
Group ID |
Instances |
Port Name |
Connection Info |
Description |
|
0 |
1 |
seed |
• Type: siICENodeDataLong • Structure: siICENodeStructureSingle • Context: siICENodeContextSingleton |
Identifies the random number sequence used for generating the locations. The seed allows two Generate Sample Set nodes to return different sets of locations by setting a different seed on each. |
|
timevarying |
• Type: siICENodeDataBool • Structure: siICENodeStructureSingle • Context: siICENodeContextSingleton |
Determines if we want to generate a different location set at each frame. |
||
|
geometry |
• Type: siICENodeDataGeometry • Structure: siICENodeStructureSingle • Context: siICENodeContextSingleton |
The geometry on which we want to generate locations. |
||
|
rate |
• Type: siICENodeDataFloat • Structure: siICENodeStructureSingle • Context: siICENodeContextSingleton |
Affects the number of locations in the generated set. The interpretation of the rate depends on the Rate Type ("ratetype") parameter: - Number per Second: the value of the rate specifies the number of locations generated each second. - Number per Frame: the value of the rate specifies the number of locations generated each frame. - Density per Second: the rate specifies the number of locations generated each second on each square unit of surface. This can be useful when generating locations on surfaces that are deformed so that the distribution doesn't get too sparse as the surface stretches out. With this option, you can turn on the Enable Max Number flag ("enablemaxnumber" parameter) and specify the maximum number of locations generated. This is required because when the rate specifies density, the number of locations generated can become extremely large as the surface area gets large. The rate also depends on the Rate Control ("ratecontrol") parameter when a filter attribute is set Possible values include: - Exact Rate: the rate is used as is on the subregion of emission - Proportional to Filtered Area: the actual rate being used will be a fraction of the specified rate. For surface emission this is done by taking the ratio of the filtered area over the geometry surface. For vertex emission this is done by taking the ratio of the number of emitting points over the total number of points. |
Outputs
|
Port Name |
Connection Info |
Description |
|
samples |
• Type: siICENodeDataLocation • Structure: siICENodeStructureSingle • Context: siICENodeContextElementGenerator |
A set of locations on the input geometry. |
See Also
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Autodesk Softimage v7.5