ChOp Sensor Input

The Channel Operator Sensor Input allows to input float values that depend on Sensors Locators into the graph of Channel Operators (ChOps).

 
A Channel Operator Sensor Input seen in the Channel Operator Editor (left) and in the Maya Node Editor (right)

Creation

Configuration

The Channel Operator Sensor Input defines the following specific attributes. For common attributes, see Channel Operator Common Attributes.

Channel Operator Attributes

Vision mode

Defines what will be extracted from the Sensor Locators. Available values are:

  • Angular Occupation (Ratio): the output will be the ratio of occupied space in the angular fuzz vision space
  • Distance Occupation (Ratio): the output will be the ratio of occupied space in the distance fuzz vision space
  • Angular and Distance Occupation (Ratio): the output will be the ratio of occupied space in the fuzz vision space (will return 1 when the vision is fully occupied, 0 when it's completely empty)
  • Maximum Angular Clearance (Angle): the output value will be the angle (in degrees) for the maximum clearance direction in the fuzz vision space (ie. the direction in which the entity can see the farthest empty space)
  • Minimum Angular Clearance (Angle): the output value will be the angle (in degrees) for the minimum clearance direction in the fuzz vision space (ie. the direction in which the entity can see the closest obstacle)
  • Spherical Occupation (Ratio): in this mode, the vision is a projection of the perception voxels onto a region of a sphere. The output is the ratio (mean value) of the region.
  • Maximum Clearance (Vector): in this mode, the vision is a projection of the perception voxels onto a region of a sphere, transformed into a distance map (the pixels around the voxel projections fade the farther they get). The output is a unit vector, which is the direction in world coordinates towards the clearance point on the sphere - the point with the lowest value on the distance map (farthest from any obstacle).
  • Minimum Clearance (Vector): same as in Maximum Clearance (Vector) mode, but the direction is towards the point with the highest value on the distance map (towards the closest obstacle)
!Ratio In Angular Occupation / Distance Occupation / Angular and Distance Occupation / Spherical Occupation modes, this option will change the output value to 1-(occupied ratio), which means it will be 1 when the vision is empty, and 0 when it's full rather than the opposite
Angle

These parameters configure the zone in which checking for obstacle in the vision (represented as green zones in the Visual Feedbacks).

  • In Angular Occupation Vision Mode:

    Angle[1] and Angle[2] define the range at which obstacles are taken into account.
    Angle[0] is used to defines a slope between Angle[0] and Angle[1] in which obstacles will only be partly taken into account at the beginning of the range.
    Angle[3] is used to defines a slope between Angle[2] and Angle[3] in which obstacles will only be partly taken into account at the end of the range.
  • In Distance Occupation Vision Mode:

    Width[0] and Depth[1] define the range at which obstacles are taken into account.
    Depth[0] is used to defines a slope between Depth[0] and Width[0] in which obstacles will only be partly taken into account at the beginning of the range.
    Width[1] is used to defines a slope between Width[1] and Depth[0] in which obstacles will only be partly taken into account at the end of the range.
  • In Angular and Distance Occupation / Maximum Angular Clearance / Minimum Angular Clearance modes:

    The maximum value amongst Width and Height x Max Distance Factor defines the radius of the radar vision (here: 6mu)
    Depth[0] defines the minimum distance for the fuzz vision space (here: 1mu)
    Depth[1] defines the maximum distance for the fuzz vision space(here: 5mu)
    Angle[0] defines the minimum angle (right side) of the fuzz vision space at its minimum distance (here: -60° at 1ma)
    Angle[1] defines the minimum angle (right side) of the fuzz vision space at its maximum distance (here: -30° at 5ma)
    Angle[2] defines the maximum angle (left side) of the fuzz vision space at its maximum distance space (here: 30° at 5ma)
    Angle[3] defines the maximum angle (left side) of the fuzz vision space at its minimum distance (here: 60° at 1ma)
  • In Spherical Occupation / Maximum Clearance / Minimum Clearance modes:

    Depth[0] defines the minimum distance for perceived obstacles
    Depth[1] defines the maximum distance for perceived obstacles
    The four Angle parameters define the limits for two angles that describe a Spherical Coordinate System :

    Angle[0] and Angle[1] are the minimum and maximum Phi (Φ), between 0 and 360° (or -180 and 180°), which is the angle between the up axis and the direction projected on the up and side plane D'
    Angle[1] and Angle[2] the minimum and maximum Theta (θ), between 0 and 180°, which is the angle between the front axis and the direction D of the perceived object
Depth
Width
Max Distance Factor Factor which will be multiplied by the greatest Depth or Width value to define the maximum distance at which computing the vision
Distance Weight Allows the vision pixels to have a value between 0 and 1 according to the distance to the perceived obstacle - entities that are farther away are less taken into account, as in the figure below - w is the distance weight, alpha (α) is the pixel value, Dmin and Dmax are the values in the Depth paramete. 

The Distance Weight is between 0 and 1. At 0 the distance is not taken into account and the pixels have the same alpha. 
Relative Velocity Weight This weight takes into account the velocity of the perceived object relative to the entity. This is projected along the front axis. The relative velocity is negative when the objects are seen as coming towards the entity and positive if the objects are seen as going away from the entity. In the figure below, rV is the relative velocity, S is the sum of the speeds of the entity and the perceived object and w the Relative Velocity Weight. The more the perceived object goes the same way as the entity, the lower its pixel alpha value. This allows lower the importance of objects that go in the same direction or away from the entity because there is no need to avoid them. If the Relative Velocity Weight is 0 the relative velocity is not taken into account and the pixels have the same alpha. The weight can be greater than 1, for example at a value of 2 the alpha will be 0 when rV is 0, which means that when a perceived object goes the same way and at the same speed or faster than the entity it will be invisible (thus not avoided).

When changing any of those value, the display of the Sensor Input will be updated automatically.

Sensor Attributes

Use All Input Sensors

Check to use all the available input sensor (ie. currently started by an Activate Sensor Behavior) on the Entity
Sensors If "Use All Input Sensors" is not checked, this list allows to determine which Sensor Locators to use. Note that any Sensor listed here should also be enabled using the Activate Sensor Behavior to be effectively used.

Additional Inputs

These inputs are only taken into account in Maximum Clearance (Vector) and Minimum Clearance (Vector) modes.

previous ChOps [0] This input gives the world direction to choose when there are no obstacles. This allows the ChOps sensor input to use the local target of a Steer behavior for example, like going towards a poptool, a mesh or following a curve. 
previous ChOps [1] When there are obstacles, the clearance will actually be the closest point to the input direction within a tolerance to the absolute minimum (or maximum) alpha. This input gives this tolerance. The default value is 0.05.  This allows to pick directions that are closer to the goal (given by the first input).