SOP to CHOP

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Summary

The SOP to CHOP uses a geometry object to choose a SOP from which the channels will be created. The channels are created from the point attributes of a SOP, such as the X, Y and Z of the point position.

From the SOP you can select a subset of the points using Point Groups. The set of attributes that are converted to channels are chosen using the names of the attributes seen on the Info popup of SOP tiles (middle mouse click on a SOP in a SOP network pane).

For data going the opposite direction, see the Channel SOP.

Note: This CHOP works in tandem with the Channel SOP. Point data is modified in CHOPs as regular channel data (samples) and then fed back to geometry as point attributes through the Channel SOP.

PythonIcon.png soptoCHOP_Class

Parameters - Geometry Page

Object / SOP - Specifies which Object / SOP contains the geometry you want to fetch.

Group - Only points within the specified group are Fetched. If blank, all points are fetched.

Method - Choose whether to get the geometry for the current frame or for all frames:

  • Static - Gets the points for the current frame only, and builds one geometry point per sample of the CHOP. There is one channel per Attribute (The default is the P attribute which creates the tx, ty and tz channels).
  • Animated - Good for looking at point XYZ coordinates over the whole animation for SOPs whose shape animates. The CHOP cooks the input once per frame (of the CHOP's frame range), and create a set of channels for every point of the SOP. This can create a lot of channels! Start and End on the Channels page can restrict the frame range that gets created.

Attribute Scope - This selects the attributes of the SOP to acquire. By default, there are three channels for the XYZ position. The "P" attribute is the point position.

You can use any attribute. If you look at the SOP's info and there are other attributes, you can specify them. For example "uv" will get the three texture coordinates. The most common attributes are

  • P - Point position (X, Y, Z) - 3 values
  • Pw - Point weight - 1 value
  • Cd - Point color (red, green, blue) - 3 values
  • Alpha - Point alpha - 1 value
  • N - Point normal (X, Y, Z) - 3 values
  • uv - Point texture coordinates (U, V, W) - 3 values

See Attributes for a complete list of attributes.

Rename Scope - This parameter matches each channel acquired in the Attribute Scope. There must be one name per attribute value. By default, it translates the P attribute (position of the point) to tx, ty and tz channels. You can use Pattern Matching to specify multiple channels.

Transform Object - If a transform object is specified, the point values will be represented relative to that object's origin and rotation.

Organise by Attribute - You can type 'pid' here - then all the channels get sorted properly.

Parameters - Channel Page

Standard Options and Local Variables

See Also