Settings and Macros/Refraction Description

This macro distorts the image using a height map to simulate the refraction or reflection effects.

Possible applications:

• The heat haze over hot ground or over and behind open fire, hot air flow from jet airplane nozzles.
• Distortion around muzzle flashes and shock waves from bomb blasts.
• Refraction of underwater objects or refraction of the environment when you look from below the water surface.
• Bubbles, water drops on a surface
• Background distortion behind transparent objects like bottles or glasses which are practically shot and need to be placed over a new background.
• Simulating the refraction and reflection in embossed surfaces like metal shields, textured glass and so on.
• Magnifying glass and spyglass effects.

Unlike the Displace tool, the Refraction macro doesn't need a center. Pixels are being shifted from the bright areas of the refraction map towards the dark ones.

Node Inputs

• Image to Distort

  Source image. Required.

  Refraction Map

  Height map which defines the shape of the refracting surface. Required.

  Refraction Power

  Map which alters the power of the effect. The brighter an area the stronger the refraction. This input uses the Alpha channel from an incoming image or a mask. Optional.

  EffectMask

  Defines the areas where the effect is applied. In contrast to Power Map it doesn't smoothly decrease the power of the effect, but blends with the original instead. Optional.

Controls Tab

• Extract height information from...

  Multi-button control. Selects a channel from the Refraction Map to use

  Soften Refraction Map

  Slider control. Makes the effect smoother

  Refraction Strength

  General effect magnitude.

  X Strength Multiplier, Y Strength Multiplier

  Slider controls. Adjust the power of the effect in the horizontal and vertical direction independently.

  X Offset, Y Offset

  Slider controls. Shift the refracted texture horizontally and vertically, but only in the areas where the refraction map is not transparent.

  Use Power Map

  Checkbox control. If you want to use an additional image as the Power Map, switch this on.

  Enable Dispersion

  Checkbox control. Allows you to use the separate refraction controls for the Red, Green and Blue channel to simulate chromatic aberrations. Switched off by default to speed up rendering in general case when you don't need this effect.

  Red Strength Multiplier, Green Strength Multiplier, Blue Strength Multiplier

  Screw controls. Adjust the power of the effect separately for the Red, Green and Blue channel.

• Tips

• Use a 32 bit float point image as the Refraction Map to get better quality.
• With this macro you can easily replicate the effect of background objects being distorted with severely defocused foreground objects around the edge. To do this, apply the Refraction to the background and feed your foreground alpha to the Refraction Map input.
• If the image you use as the Refraction map is changing quickly and you want to see motion blur in the final result of the Refraction, slow your refraction map down N times to get subframes, then perform slowed-down refraction, then apply the Duplicate tool with Copies = N and Time Offset = 1, then speed the result up N times.

Refraction_Example.comp - an example of using the Refraction macro

Download Refraction_v03 (for Fusion 5.x)

Download Refraction_v07-3

Development History and Discussion on PigsFly

To install the macro, place the downloaded Refraction_v07-3.setting file to your Fusion:\Macros folder.
Then you can insert it to the Flow either choosing from the main menu: Tools>Macro or by pressing Ctrl+Space and typing the tool name.

Gregory Chalenko