ZapFrom Generates multiple lightning bolts outwards from the edges of objects in the FromObj input clip, and renders them over a background input. Use the Show:Edges option to view the source edges while adjusting the Threshold and Blur From Obj parameters. Inputs: FromObj:  The edges of objects in this clip are extracted, and the lightning starts at points along these edges. Back:  The clip to use as background.

Parameters:

Surface Bolts:   Integer,  Default: 25,  Range: 1 or greater.
The number of points along the edges to generate lightning bolts from. These surface bolts are divided up amongst the isolated shapes in the FromObj input, proportionally to the sizes of the shapes.

Threshold:   Default: 0.5,  Range: 0 or greater.
The value used to determine the edge locations. Objects darker than this value are ignored. On smooth objects, larger threshold values move the edges inwards to make smaller shapes, and smaller values move the edges outwards. You can use the Show Edges option to view the edge image directly while adjusting this parameter.

Blur From Obj:   Default: 0.1,  Range: 0 or greater.
Blurs the FromObj input clip before finding the edges. This can help remove noise, and reduce the number of separate shapes. You can use the Show Edges option to view the edge image directly while adjusting this parameter.

Show:   Popup menu,  Default: Result.
Selects the output option.

Result:  shows the normal lightning result over the background.

Over FromObj:  shows the lightning over the FromObj input instead of the Back. This can be useful while adjusting the number of surface bolts.

Edges:  shows the edge image. This can be useful to view while adjusting the Threshold and Blur From Obj parameters.

Max Length:   Default: 0.25,  Range: 0 or greater.
Scales the length of the bolts.

Vary Length:   Default: 0.5,  Range: 0 to 1.
The amount to randomly vary the length of each bolt. A value of 0 makes all bolt lengths equal to Max Length, and a value of 1 makes bolt lengths between zero and Max Length.

Vary Spacing:   Default: 0.5,  Range: 0 or greater.
The amount to randomly vary the starting point of each bolt along the edges. A value of 0 makes the bolts regularly spaced, and value of 1 make the bolts randomly spaced.

Width:   Default: 0.1,  Range: 0 or greater.
The width of the lightning bolts.

Vary Width:   Default: 0,  Range: 0 to 1.
The amount of random variation in the width of the bolts along their lengths.

End Pointiness:   Default: 1,  Range: 0 to 1.
Determines how pointed the end of the bolts are. If 0, the entire bolt will have equal width. If 1, the bolts will thin out along their entire length for a pointed end. If it is .5, the bolts will start thinning out half way between the start and end points.

Wiggle Start:   Default: 0,  Range: 0 or greater.
By default the bolts automatically wiggle over time. This parameter provides a starting offset for these bolt perturbations.

Wiggle Speed:   Default: 1,  Range: 0 or greater.
The speed at which the bolts are perturbed automatically over time. To animate changes in speed, set this to zero and animate the Wiggle Start parameter instead.

Jitter Frames:   Integer,  Default: 0,  Range: 0 or greater.
If this is 0, the same random lightning will be used for every frame processed. If it is 1, different random lightning is used for each frame. If it is 2, new random lightning is used for every other frame, and so on.

Rand Seed:   Default: 0.123,  Range: 0 or greater.
Used to initialize the random number generator. The actual seed value is not significant, but different seeds give different random lightning bolts, and the same value should give a repeatable result.

Brightness:   Default: 1,  Range: 0 or greater.
Scales the brightness of the lightning bolts.

Color:   Default rgb: [1 1 1].
The color of the lightning. If you want to keep the lightning bolt itself bright white, you can still affect the perceived color by adjusting the Glow Color instead.

Wrinkle Amp:   Default: 1,  Range: 0 or greater.
Scales the amount of wrinkles in the bolts. Decrease for straighter smoother bolts or increase for more kinky bolts.

Curve Amp:   Default: 0.5,  Range: 0 or greater.
Similar to Wrinkle Amp but affects the general path of the bolt. If decreased, the bolt will stay closer to the line between the Start and End points. If increased it can wander further away from this line. This differs from the Wrinkle Amp parameter in that it can be used to make straighter bolts while still keeping the wrinkles at the detailed level.

Branchiness:   Default: 1,  Range: 0 to 10.
Scales the number of additional bolts that branch from the main bolt. Set this to 0 for basic bolts with no extra branches.

Branch Angle:   Default: 65,  Range: 0 to 180.
The maximum angle of the random branches relative to the bolt they are branching off of. If this is 0 the branches will be more lined up with the main bolt. With larger values the branches will be more perpendicular to the main bolt.

Branch Length:   Default: 0.5,  Range: 0 to 1.
The maximum length of the branches relative to the distance between the Start and End points.

Scale Back:   Default: 1,  Range: 0 or greater.
Scales the brightness of the background before combining with the lightning. If 0, the result will contain only the lightning image over black.

Combine:   Popup menu,  Default: Screen.
Determines how the lightning and glow are combined with the Background.

Screen:  performs a blend function which can help prevent overly bright results.

Add:  causes the lightning to be added to the background. This gives brighter glows over light backgrounds.

Params2:

Start Offset:   Default: 0,  Range: 0 to 1.
The offset from the start point to begin drawing the bolts. This can be useful for animating a lightning strike.

Length:   Default: 1,  Range: 0 to 1.
The length of the bolts, beginning at Start Offset. If less than 1, the bolts will not be drawn all the way from start to end. This can be useful for animating a lightning strike.

Glow Parameters:

Glow Bright:   Default: 2,  Range: 0 or greater.
Scales the brightness of the glow applied to the lightning.

Glow Color:   Default rgb: [0.5 0.5 1].
The color of the glow applied to the lightning.

Glow Width:   Default: 0.2,  Range: 0 or greater.
The width of the glow applied to the lightning.

Glow Width Red:   Default: 0.5,  Range: 0 or greater.
The relative red width of the glow.

Glow Width Grn:   Default: 1,  Range: 0 or greater.
The relative green width of the glow.

Glow Width Blue:   Default: 1.5,  Range: 0 or greater.
The relative blue width of the glow.

See Also:

ZapFromMask

Zap ZapTo

Sapphire Plug-ins Introduction

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