Dynamics channel node

Extracts any information from a DOP simulation that is accessible through the dopfield expression function.

The most common use for this CHOP is to extract translation and rotation channels from DOP objects to apply to Geometry Objects. But you can also use it to extract collision information, velocity values, constraint information, and so on.

You can use wild cards when choosing the information to extract, so it is very easy to extract large volumes of information from a simulation.

Parameters

Dynamics

DOP Path

The path to the DOP data to extract the information from. This consists of a DOP Network path, an object specification, and a data name. The format of the string is: dopnet:objectspec/datapath, just as in the dopfield expression. The objectspec can contain wildcards to match a number of objects, but the dopnet and datapath components do not support wildcards. If just a DOP Network path is specified in this parameter, such as /obj/dopnet1, then it is assumed that the Position information from all objects in that DOP Network should be extracted. An equivalent value for this parameter would be /obj/dopnet1:*/Position.

Record Name

This parameter controls which record within the simulation data is to be examined. The most common value is Options which is where most simulation data stores its attributes. In the case of impact information, this field would be Impacts.

Record Numbers

This numerical pattern specifies the record numbers from which this CHOP should extract its information. The Options record generally has only one record. But when extracting impact information, a value of "*" can be used to extract all impact records. A range can also be specified. "0-4" can be used to extract the first five impact records.

Field Names

Controls which fields are extracted from the chosen records in the simulation data. This field accepts wild cards. To extract just the translations and rotations from Position data, for example, set this parameter to "t? r?". To extract all available fields, use the default value of "*".

Include Record Number In Track Name

If multiple records are being extracted from the simulation data, you should turn on this option to ensure the channel names created for each record are unique. Otherwise, the values from each record will overwrite the values from the previous record. This parameter defaults to being off because when extracting only a single record the numerical suffix is generally not useful.

Method

Controls the way data is extracted from the DOP Network.

Dynamic	The CHOP extracts only the data from the current timestep. Whenever the DOP Network changes to a new timestep, the values in this CHOP are updated.
Cached	The CHOP cooks the DOP Network for the whole duration of the CHOPs time range. All data is extracted and preserved. Changes to the DOP Network do not cause this CHOP to recook, as that could be very time consuming. To update Cached values in this CHOP, use the Update button.

Update

Forces this CHOP to resimulate the DOP Network and recache all values if the Method parameter is set to Cached. Pressing this button is the only way to update the Cached values.

Examples

The following examples are specifically designed to demonstrate this node:

ExtractTransforms

$HFS/mozilla/documents/examples/nodes/chop/dynamics/ExtractTransforms.cmd

The following examples use this node:

Lookup

$HFS/mozilla/documents/examples/nodes/chop/lookup/LookupCHOPExample.otl