| Line Parameters |
These parameters affect the type of lines used to draw the loose and sketchy strokes.
| Keyframing the Line Parameters |
Keyframe Buttons
If only one frame has been loaded, keyframing will not be allowed, and the "key" button will be inactive.
If no keyframes are set for the parameter in any frame of the animation, the "key" button will have a plain, black font.
If a keyframe is set for the parameter in the current frame, the "key" button will have an italicized, purple font.
If a keyframe is set for the parameter in a frame other than the current frame, the "key" button will have a bold, purple font.
Setting a Keyframe
To keyframe the parameter, left click the "key" button. This will set a keyframe at the current frame with the current parameter value.
How the Parameters for Inbetween Frames are Set
If only one keyframe is set, its value will be used for the parameter value in all frames.
The parameter value for all frames before the first keyframe will be the same as the parameter value of the first keyframe. Likewise, the parameter value for all frames after the last keyframe will be the same as the parameter value of the last keyframe.
The parameter values for frames between any two keyframes depends on how the two keyframes are set. Click on the keyframe button next to a parameter in the lines tab of this manual to see more on how that parameter's keyframing is handled.
Removing a Keyframe
To remove the keyframe set at the current frame, right click the "key" button.
When No Keyframes are Set
When no keyframes are set, the parameter value for each frame will be whatever is currently chosen in the interface.
| Number of Strokes |
 40 strokes |
 240 strokes |
The number of strokes to draw in a loose and sketchy render is the number of strokes that are attempted (the number of particles that attempt to be born) during the render. The actual number of strokes that are drawn may be less than the amount specified. This is because as the loose and sketchy image is being drawn, it may become too crowded with strokes for a new stroke to be started. Also, as the edge image is being erased, the renderer may have trouble finding an edge on which to start a new stroke.
After an image is rendered, the program will write to standard output the actual number of strokes that were drawn.
Setting the Number of Strokes to Draw
To set the number of strokes to draw in the loose and sketchy image, type a number in the "Number of Strokes to Draw" window, or use the mouse like a slider to change the number. Moving the mouse from left to right in the window while left clicking increases the value by one. Moving the mouse from left to right in the window while middle clicking increases the value by ten. Moving the mouse from left to right in the window while right clicking increases the value by one hundred. Moving the mouse in the opposite direction decreases the value by the stated amounts.
Keyframing the Number of Strokes
The value for the "Number of Strokes to Draw" parameter for frames between two keyframes is found by linearly interpolating the number of strokes from the first keyframe to the second.
For more on keyframing, see "Keyframing the Line Parameters" above.
| Stroke Density |
more dense |
 less dense |
The "Stroke Density" parameter controls how far a new stroke has to be from a previously drawn stroke. Maximum density allows strokes to be drawn very close to other strokes. Minimum density increases the distance a new stroke has to be from a previously drawn stroke.
Setting the Density of the Strokes
To alter the density of the strokes drawn in the loose and sketchy image, move the "Stroke Density" slider. When the slider is all the way to the left, the strokes drawn will be less dense. When the slider is all the way to the right, the strokes will be more dense.
The value for the "Stroke Density" slider for frames between two keyframes is found by linearly interpolating the position of the slider (and thus the amount of density) from the first keyframe to the second.
For more on keyframing, see "Keyframing the Line Parameters" above.
| Stroke Width |
2 to 2 pixels |
 1 to 3 pixels |
The stroke width can vary along the stroke. Several short line segments are joined together to create each stroke. Each line segment may have a different width at each endpoint. Shared endpoints of line segments within the stroke have the same width. This creates the look of a varied width line.
Setting the Stroke Width
To set the stroke width, type the number of desired pixels for the minimum and maximum width in the "Stroke Width" windows, or use the mouse like a slider to change the number. Moving the mouse from left to right in a window while left clicking increases the value by one. Moving the mouse from left to right in a window while middle clicking increases the value by ten. Moving the mouse from left to right in a window while right clicking increases the value by one hundred. Moving the mouse in the opposite direction decreases the value by the stated amounts.
To have the width remain constant along the stroke, set both widths to the same value.
What the program does with these values is randomly choose numbers from within the range that has been set for the widths of the endpoints of the line segments making up the strokes. Shared endpoints share a common width.
Caution! The line segments making up the stroke are very short. Having minimum and maximum width values that greatly differ from each other will cause drastic changes in the width along the stroke. When the two widths do not greatly differ from each other, the variance of the width along the stroke will appear more natural.
1 to 3 pixels |
 1 to 6 pixels |
The values for each of the stroke widths for frames between two keyframes are found by linearly interpolating each width value from the first keyframe to the second.
For more on keyframing, see "Keyframing the Line Parameters" above.
| Varying the Width by Depth or Intensity |
 1 to 5 pixels |
 5 to 1 pixels |
One way to vary the width is randomly, as shown above. Another technique provided is to vary the width of the stroke by depth or intensity. In a depth image, the intensity of the image is used to indicate the depth of the geometry represented. To emphasize this in the loose and sketchy render, varying the width by depth or intensity could be used to draw a different width stroke at different areas in the image depending on the intensity of the input image. The technique also works for non-depth input images, based on the intensity of the image.
Setting the Width Variance Type
To vary the width by depth or intensity, first click the "Vary Width by Depth/Intensity" toggle switch. Then set the desired width range in the "Stroke Width" windows.
Set the width in the first width window to control the width of lines for the darkest area of the image. Set the width in the second width window to control the width of lines for the lightest area of the image. The width of the stroke will change within this range as the intensity changes. For instance, a stroke drawn from a dark area to a light area will gradually change widths from the first width value to the second width value.
When the "Vary Width by Depth/Intensity" toggle switch is off, stroke width will be randomly varied between the two width values.
Keyframing the Width Variance Type
The value for the "Vary Width by Depth/Intensity" toggle switch for frames between two keyframes is found by holding the value of the first keyframe constant until the second keyframe.
For more on keyframing, see "Keyframing the Line Parameters" above.
| Taper Stroke Endpoints |
not tapered |
 tapered |
Endpoint tapering is used to bring the ends of the strokes to a point, rather than having an abrupt end to the stroke.
Setting the Endpoint Tapering
To turn on endpoint tapering, click the "Taper Endpoints" toggle switch.
Keyframing the Endpoint Tapering
The value for the "Taper Endpoints" toggle switch for frames between two keyframes is found by holding the value of the first keyframe constant until the second keyframe.
For more on keyframing, see "Keyframing the Line Parameters" above.
| Limiting the Stroke Length |
no limit |
 limit = 2 pixels |
Normally, the stoke will continue to be drawn until it goes out of range (off an edge in the edge map or off the image plane). However, the stroke can be stopped at a certain length if the "Maximum Stroke Length" toggle switch is on. This parameter is used to set the maximum length of a stroke. A stroke may end sooner than the maximum length if it goes out of range.
Setting the Maximum Stroke Length
To turn on the stroke length limit, click the "Maximum Stroke Length" toggle switch. Then set the maximum length desired (in pixels) in the window.
To set the maximum length, type a number in the "Maximum Stroke Length" window, or use the mouse like a slider to change the number. Moving the mouse from left to right in the window while left clicking increases the value by one. Moving the mouse from left to right in the window while middle clicking increases the value by ten. Moving the mouse from left to right in the window while right clicking increases the value by one hundred. Moving the mouse in the opposite direction decreases the value by the stated amounts.
The value for the "Maximum Stroke Length" toggle switch for frames between two keyframes is found by holding the value of the first keyframe constant until the second keyframe.
If the "Maximum Stroke Length" is toggled on for both keyframes, the maximum length value is linearly interpolated between the two keyframes. If only the first keyframe is toggled on, the maximum length value is held constant until the next keyframe.
For more on keyframing, see "Keyframing the Line Parameters" above.
| Antialiasing the Strokes |
antialiased |
 not antialiased |
Antialiasing is used to draw strokes that appear smooth. Antialiasing is achieved by weighting the intensity of the lines, so the color of the line will sometimes be blended with the background. To draw absolutely solid lines that may not appear as smooth, do not use antialiasing.
Setting the Antialiasing
To turn on antialiasing, click the "Draw Smooth Strokes" toggle switch.
The value for the "Draw Smooth Strokes" toggle switch for frames between two keyframes is found by holding the value of the first keyframe constant until the second keyframe.
For more on keyframing, see "Keyframing the Line Parameters" above.