|On this page|
This CHOP outputs X and Y screen values for the mouse device.
The Mouse X and Y positions are output through the channels named in the Position X and Y parameters, when the Active button is enabled.
The range of the mouse values are
+1 in X, and
+0.8 in Y.
0, 0 is the center of the screen.
The Mouse and Keyboard CHOPs are often connected to the Position and Active inputs respectively of the Record CHOP to enable the recording of channels generated by the Keyboard and Mouse.
While on, the mouse movement will be output from the CHOP, and the CHOP will cook every frame. Otherwise the CHOP will not cook and the current mouse X or Y values will not be output.
The name of the channel that records the horizontal movement of the mouse.
The name of the channel that records the vertical movement of the mouse.
If enabled, and a tablet is connect to the system, the current parameters of the stylus will be reported.
How hard the stylus is pressing on the tablet. A value of
represents no pressure, while
1 is maximum pressure.
The direction the stylus is facing on the tablet. If the
stylus tip is facing the top of the tablet, it is
facing the right side, it is
The angle off the horizontal of the stylus. A value
the stylus is lying flat. A value of
90 means the stylus is
pointing straight down. Negative values mean the stylus is
The angle to which the stylus is twisted about its own
length. Again, a value from
0-360 in degrees.
Which tool is currently active.
0 means a mouse-like device,
1 means a pen, and
2 means an eraser.
Some of these parameters may not be available on all CHOP nodes.
To determine the channels that are affected, some CHOPs have a scope string. Patterns can be used in Scope, for example
* (match all), and
? (match single character).
The following are examples of possible channel name matching options:
Matches a single channel name.
chan3 tx ty tz
Matches four channel names, separated by spaces.
Matches each channel that starts with
Matches each channel that has
foot in it.
? matches a single character.
t? matches two-character channels starting with t.
Matches number ranges, giving
[xyz]matches three characters, giving channels
Sample Rate Match
The Sample Rate Match options handle cases where multiple input CHOPs’ sample rates are different.
Resample At First Input’s Rate
Use the rate of the first input to resample the others.
Resample At Maximum Rate
Resample to the highest sample rate.
Resample At Minimum Rate
Resample to the lowest sample rate.
Error if Rates Differ
Does not accept conflicting sample rates.
The units of the time parameters.
For example, you can specify the amount of time a lag should last for in seconds (default), frames (at the Houdini FPS), or samples (in the CHOP’s sample rate).
When you change the Units parameter, the existing parameters are not converted to the new units.
Time slicing is a feature that boosts cooking performance and reduces memory usage. Traditionally, CHOPs calculate the channel over its entire frame range. If the channel needs to be evaluated every frame, then cooking the entire range of the channel is unnecessary. It is more efficient to calculate only the fraction of the channel that is needed. This fraction is the Time Slice.
Causes the memory consumed by a CHOP to be released after it is cooked, and the data passed to the next CHOP.
The Export Prefix is prepended to CHOP channel names to determine where to export to.
For example, if the CHOP channel was named
geo1:tx, and the prefix was
/obj, the channel would be exported to
You can leave the Export Prefix blank, but then your CHOP track names need to be absolute paths, such as
Every CHOP has this option. Each CHOP gets a default color assigned to it for display in the graph, but you can override the color with the Graph Color. There are 36 RGB color combinations in the palette.
Graph Color Step
When the graph displays the animation curves, and a CHOP has two or more channels, this defines the difference in color from one channel to the next, giving a rainbow spectrum of colors.