Working with the BCC Ripple Filter

Transcription

1 Working with the BCC Ripple Filter The Ripple Þlter simulates ripples spreading out from a point of origin in a pool of water, similar to what you see after tossing a pebble into a pond. This Þlter automatically creates animated ripples and allows you to choose from a range of wave shapes. Source image Filtered image The Ripple Þlter includes extensive parameters for you to customize. You may need to scroll to see them all. The illustration at right does not show all the parameters. The BCC Ripple Þlter can also be used as a transition. To apply a Ripple as a transition, use the BCC TR Ripple in the BCC Transitions category or apply the Þlter to two layers. General Controls Parameter Group At times, you may want to view your clip without the effect that you ve applied. The Bypass Effect checkbox lets you view the source footage without the effect. When the Bypass Effect checkbox is selected, it turns pink. When you applied a BCC effect to an Avid title or matte, enabling the Bypass Effect checkbox does not display the original title unþltered, but rather displays the nested Graphic Fill of the matte key. Bypass Effect is a parameter change; selecting the Bypass Effect checkbox will unrender a rendered effect. To bypass a rendered effect without unrendering, step into the effect in the Avid timeline to see the unaffected video.

2 Selecting the Safe Colors checkbox enables an NTSC/PAL color-safe Þlter that allows only colors that are safe for broadcast. BCC allows RGB values across the full range. When this checkbox is selected, the RGB values are limited to the NTSC/PAL safe range of The Draft Mode checkbox allows you to preview your effect in a Draft Mode to speed previews. This is especially useful for effects with multiple track inputs. Deselect this option before rendering your effect. The Apply to Title-Matte checkbox allows you to apply BCC Þlters to titles created in Avid s Title tool. To apply an effect to a title, drag the effect onto the title (you do not have to Option-drag) and select the Apply to Title-Matte checkbox. The Invert Matte checkbox allows you to invert any matte created by your effect. This is useful when you work with imported images. The Layer Opacity slider sets the opacity of the Þlter layer, which allows you to fade effects. When Apply to Title-Matte checkbox is selected, Layer Opacity affects the graphic Þll layer, which allows you to fade titles. The Field Render menu sets the rendering optimization for BCC. For most Þlters, you can use the default of Speed Optimized. For effects that include edging or DVE moves, you may want to use Quality Optimized. Quality Optimized takes more time to render, but will generally correct any problems with jitter or rough edges on effects. Geometrics Parameter Group The controls in the Geometrics parameter group allow you to add basic DVE moves to any Þlter. The Geometrics parameter group includes the following controls. Selecting the Enable Geometrics checkbox allows you to use the parameters to reposition a track. When this checkbox is deselected, the other parameters have no affect. Position X and Position Y adjust the horizontal and vertical location of the track. Scale X and Scale Y change the size of the image along the X and Y axis, respectively. These parameters scale as percentages of the image s original width and height. Thus, a Scale X value of 200 produces an image twice as wide as the original. Select the Lock Scale checkbox to keep the Scale X and Y values in proportion.

3 Tumble, Spin, and Rotate change the image s perspective along the X, Y, and Z axes respectively. Tumble, Spin, and Rotate can animate over values greater than 360 in order to make the shape complete more than one full revolution. Tumble Spin Rotate The Crop controls crop the edges of the image. Left Crop, Top Crop, Right Crop, and Bottom Crop determine the width, in pixels, of the cropped area on each edge of the image. For the Crop controls refer to the sides of the original image before it is transformed in 3D space. For example, if you tumble an image 180 so that it appears upside-down, cropping the Top affects the top of the original image, which is actually the bottom of the tumbled image. The Blend control soften the edges of the image by reducing their opacity. The Blend parameter determines the width, in pixels, of the transparent band on each edge of the image. These values are unaffected by the Crop values, allowing you to soften the edges of an uncropped image. Drop Shadow Parameter Group The controls in the Drop Shadow parameter group allow you to add an animatable drop shadow to an effect. The Drop Shadow parameter group includes the following controls. The Enable Drop Shadow checkbox turns the shadow on and off. If this checkbox is not selected, the other parameters have no affect. Source Opacity sets the opacity of the source. You can use this parameter to fade in a title or other source, without fading in the shadow. Distance sets the distance (in pixels) between the shadow and the image. Intensity sets the opacity of the drop shadow, and is scaled as a percentage. At a value of 100, the shadow is completely opaque. Lower Intensity values allow the background image to be seen through the shadow. At a value of 0, the shadow is completely invisible.

4 Softness controls the softness of the edges of the shadows. A setting of 0 produces a sharply deþned shadow with hard edges. Increasing Softness produces shadows with softer edges. Angle sets the direction of the drop shadow. A setting of 0 places the shadow to the right of the image; a setting of 90 places it directly below the image. Shadow Color sets the color of the shadow. If the source image is opaque, selecting the Opaque Source checkbox can speed rendering and previews. If your source is partially transparent, deselect this option for best results. Ripple 1 Parameter Group If the Correct Non-Square Pixels checkbox is selected and the Þlter is applied to media with non-square pixels, the Þlter converts the pixels to square pixels (maintaining the height), apply the ripple, and then convert the pixels back to their original format. This helps to prevent distortion. Radius determines the radius of the full-strength ripple. Points within the range set by the Radius value will be fully displaced by the ripple. The ripple waves decay as they move beyond the range of the radius, and points more than two times the radius from the center are not affected by the ripple (when Falloff is at 0). For example, if you set Radius to 50, all pixels within 50 units of the Center Point are fully distorted by the ripple. Points between 50 and 100 units are affected less as the value approaches 100. Pixels beyond this range remain unaffected. Radius=160 Radius=80 Center Point Parameter Group Center Point sets the coordinates of the center point of the ripple on the X and Y axis. Note that the center point must be placed within the source image.

5 Ripple 2 Parameter Group Height determines the amount of displacement in the direction of wave motion. Height=50 Height=100 Perpendicular Height determines the amount of displacement perpendicular to the direction of wave motion. Perpendicular Height=0 Perpendicular Height=50

6 Wave Width determines the distance between the peaks of the ripple waves. The Wave Width does not affect the maximum displacement of each point in the image, but does affect how fast the displacement changes from point to point in the image. Wave Width also affects the number of waves in the effect, because as the waves become wider, fewer Þt on screen. Wave Width=40 Wave Width=20 Speed and Phase control the motion of the ripple waves as they move from the center of the ripple. Speed controls the rate at which the waves move, and Phase controls the position of the waves. The default Speed setting is 10 moves the ripple out by one wave width per second. A negative Speed value moves the ripples in toward the center. When Speed is set to 0, the ripple is stationary (unless Phase is animated). The Speed and Phase controls provide several ways to control the movement of your ripple over time. Leave Phase at its default setting and adjust Speed. Try this technique if you care about the overall motion of the effect but not about the exact number of waves created. If you want to precisely control the point in the waveform at which the Ripple begins (for example, whether it begins at a peak or a trough), move the position indicator to the Þrst frame of the effect and adjust the Phase control until the wave is at the desired point. If you want to control the number of waves that move out over the duration of the clip, set Speed to 0 and animate Phase to create movement. For example, suppose you want exactly Þve waves to form and disperse during the clip. At the Þrst keyframe of the clip, set Phase to 0. Set the keyframe at the last frame in the clip to 1800 (5 x 360 ). Exactly Þve full waves form over the duration of the clip. If you want a static (not animated) distortion, set Speed to 0 and do not animate Phase.

7 Inside Radius sets the radius of a circle at the center of the ripple within which no distortion takes place. You can animate this parameter to produce a ripple that does not continuously ßow outward from the center, but instead produces a few concentric ripples that move outward and disappear. Inside Radius=0 Inside Radius=80 Falloff controls the rate at which the wave height drops off beyond the edges of the radius. Increasing Falloff causes the wave height to decrease more slowly (thereby creating a wider falloff area), and decreasing this value makes the wave height decrease more abruptly. Chaos Parameter Group The Chaos parameters provide more options for controlling the appearance of the ripple, which can be useful for creating more realistic effects. The Twirl menu affects the behavior of the angular portion of the wave. The Twirl settings have no affect if Perpendicular Height is set to 0. When Twirl is set to Off, Perpendicular Height creates the same amount of displacement in the center of the ripple as it does at the edges. When Twirl is set to On, the displacement caused by the Perpendicular Height increases farther from the center. Super Twirl and Hyper Twirl further exaggerate the angular motion as the wave moves away from the center of the ripple. Twirl On Twirl Hyper

8 The WaveForm setting determines the shape of the wave. The choices fall into two categories: Shape waveforms and Spectrum waveforms. The Shape waveforms include Sine, Triangle, Square, Sawtooth, Circle, Semi-Circle, Uncircle, and Half-Sine. These names refer to the shape repeated on a graph that plots the displacement of each point in the wave on the Y axis and the distance of each point from the center on the X axis. The Shape waveforms are mathematically derived and are not intended to look natural. For a more natural-looking alternative, experiment with the Spectrum waveforms. These are all variations on the sine wave that produce more realistic waves. The Chaos Wave s waveform is determined by the Chaos Wave value, which relates to the fourteen Spectrum waveforms listed in the WaveForm menu. A Chaos Wave value of 10 uses the Spectrum 1 waveform, 20 uses the Spectrum 2 waveform, and so on. Values between two multiples of 10 create a mix of the two adjacent Spectrum waves. Chaos Blend controls the mix of the speciþed Waveform (determined by the WaveForm menu) with the Chaos Wave setting. If Chaos Blend is set to 0, the resulting wave conforms to the WaveForm setting. At a Chaos Blend value of 100, the Þlter uses only the Chaos Wave setting. Intermediate values blend between the two. You can change the Chaos Blend value to adjust the amount of chaos added to the basic waveform. Wave Distortion distorts the shape of the wave, changing the displacement of pixels that are not at zero points (for positive values) or peaks (for negative values) in the wave. A zero point is a point in a wave which is not displaced; if you image a waveform drawn on a graph, the zero points are the points at which the wave crosses the horizontal axis. The Intensity menu adjusts the affect of the Height and Perpendicular Height settings on the ripple. Normal has no affect on the Height and Perpendicular Height settings and is suitable in most circumstances. Low scales down the Height and Perpendicular Height values by a factor of 10, which can be useful if you are working with small ripples and want Þne control over the parameters. High multiplies the Height and Perpendicular Height values by a factor of 10 and can produce very exaggerated and unnatural-looking ripple effects. You can stretch or squeeze the area affected by the ripple in any direction by using Stretch and Stretch Angle. Positive Stretch values stretch the ripple, while negative values squeeze it. The Stretch Angle is the angle between the stretch direction and the horizontal axis. Stretch is useful for adjusting the perspective of the ripple. For example, you can create the appearance of a ripple in water viewed from the shore rather than from above. To achieve this effect, adjust the Stretch slider to a high value (between 75 and 100), and leave Stretch Angle at the default of 0. This effect generally looks best

9 if Wave Width is decreased, which adds to the illusion of perspective by making the waves look closer together. In the following examples, the PixelChooser is used to apply the Þlter to a rectangular area ending at the horizon. Source image Filtered image with Stretch If you see holes or tearing in the ripple after you stretch it, scale down the Stretch and Height parameters or adjust the Pinning controls to compensate. Light Parameter Group The Light parameters adjusts the lighting of the ripple in the Þltered image. Light Level controls the amount of light applied to the image. At a value of 0, no light is applied. As the value increases, the light becomes more intense. Light Color sets the color of the applied light. Light Width affects the size of the lit area on the wave crest. Increasing this parameter value causes a wider part of the crest to be lit; decreasing it diminishes the lit portion of the wave. Light Width=20 Light Width=80

10 Light Focus adjusts the shape of the light over each wave. Increasing Light Focus makes the light wider and more diffuse; decreasing Light Focus makes the light sharper and narrower. Light Focus= 80 Light Focus=80 Light Angle sets the angle at which the light hits the surface of the waves. Light Elevation determines the distance between the light source and the image plane. As Light Elevation increase, the light hits a larger portion of the ripple. Light Elevation=20 Light Elevation=80 Ambient Light adjusts the diffuse light on the image. The default of 100 does not add or subtract ambient light from the source image. Decreasing this setting makes the image darker before the other light is applied. Ambient Light illuminates or darkens the image evenly, and is unaffected by any other lighting parameters. The PixelChooser does not affect Ambient Light. Ambient Light is applied to all pixels. This ensures that the PixelChooser does not create discrepancies in the overall lighting of the image before Wave is applied. At the default Ambient Light value, the PixelChooser behaves exactly as in other Þlters; at other values, the PixelChooser Þlters every parameter except Ambient Light. The Apply Mode menu controls how the Þltered image is composited with the source image. The User Guide contains detailed descriptions of all the Apply Modes.

11 PixelChooser Parameter Group The PixelChooser is included in many Boris Þlters and provides several methods to selectively Þlter an image. You can use the PixelChooser to create a matte between Þltered and unþltered pixels, either by specifying a geometric region or by using the image s luma or color information. See the individual PixelChooser Þlter for more detailed information on the PixelChooser controls. Working with the Pinning Controls A displacement Þlter might distort the image in such a way that it creates holes at the edges of your image, or, at more extreme settings, tears holes in the center of your image. The pinning controls can counteract this effect by undistorting the image at speciþed edges, or in regions around up to two chosen points ( pin points ) within the image. No Pin Pin All Edges The most important control on this section is Edge Pin, which determines which edges are pinned. You can pin any or all of the edges, the center of the image, or only the horizontal or vertical edges. The default setting pins all the edges, which prevents edge distortion at most parameter settings. However, pinning cannot always prevent tearing at extreme settings. Increasing Edge Pin Width can help by undistorting within a greater distance from the edges. For effects that involve less distortion, a smaller Edge Pin Width prevents the edges from tearing and looks more realistic. Pin Point 1 and Pin Point 2 Parameter Groups Pin Point 1 and Pin Point 2 set the coordinates of a pin point. A pin point is a point at which the image is undistorted. The remaining Point 1 controls affect the distortion in a circular region (the pin region) centered around this point. The Pin Point 2 parameters apply a second pin point. These parameters function identically to the Pin Point 1 controls.

12 Point 1 Strength sets the amount of pinning applied to the image at the pin point. The default value of 100 completely undistorts the pin point. Decreasing values reduce the effect of the pin point, and at a value of 0, the point undergoes the full distorting effect of the Þlter. In other words, when Point 1 Strength is 0, the Pin Point 1 has no affect. Point 1 Range sets the radius (in pixels) of the Pin Point 1 region. Point 1 Center % sets the percentage of the pin region for which the pin is fully applied. For example, if you set Point 1 Range to 100, and Point 1 Center % to 50, then pixels within 50 pixels (50% of the Point 1 Range setting) are completely undistorted, and pixels within 50 to 100 pixels are partially undistorted.