AutoBrush – FilterForge filter

AutoBrush is a painting filter I wrote in Lua for my own postwork needs. It distributes brushes/images over an image procedurally, similar to the standard bomber component in FilterForge.

The filter is free to download here:

You will need a copy of FilterForge version 7 or higher to use the filter.

First update 2021-02-27:

version 1.1

  • Fixed a bug that would sometimes cut off certain brushes halfway if they had a brush size of 50 or less.
  • Added another locked checkbox called DoubleStrokes. Once this is checked, the number of brush strokes will double. Warning: this is only for users with a high performing PC. If the stroke number is set to 500, it will be 1000 instead once this box is checked, increasing the rendering time substantially.
  • Changed the last presets, number 10-14.

Easiest way to apply the filter from PhotoShop:

  1. In PhotoShop, select the drop-down Filter –> FilterForgeFilterForge version X
  2. You find AutoBrush in the Creative folder inside FilterForge.
  3. Apply a preset.
  4. Uncheck the UserImageOn checkbox to use the image you brought from PhotoShop.
  5. At the bottom of the sliders panel to the left, lock “Size, pixels” at maximum resolution. You don’t want to randomize this slider.

How to improve the render speed:

  1. Keep “StrokeCap–300” checked for faster performance, it will cap the strokes at maximum 300. If you want more strokes you need to uncheck this.
  2. Lock “EdgeBrushes” at 1 for best performance. This slider adds extra strokes that are applied on edge areas.
  3. Set “LongerStrokes” to 1 for best performance. This slider causes some strokes to get lengthened in a random direction, with some amount of rotation and decreasing size.
  4. Set “LongStrokeChance” to 1 for best peformance. This is the percentage chance for every stroke to get lengthened. Be careful, a high value for this slider will significantly slow down the render time.
  5. The “Speed” slider will speed up the render but also results in a loss of quality.

Adding your own pre-made brushes:

You can add your own pre-made brushes in .png format by following these steps:

  1. Edit the filter by pressing the button up to the top right; “Filter Editor”.
  2. Save the filter with a new name so that your changed filter is a separate variant from the original filter.
  3. The mapscript already comes with 8 standard presents for brushmaps that you plug in. The image below shows the first 3 presets that have 100, 16 and 16 brushes in each brushmap. Presets 4-8 are designed for user-imported grids of brushes. The slider “Select Brushmap” selects between these 8 presets.

Inside the main Lua mapscript, find this function:

“function InitBrushSelection()”

Inside this function you find 8 Switch statements that define parameters for each of the 8 brushmap presets. Find the Switch statement that corresponds to the brushmap you want to edit.

If you have a grid with 10 * 10 brushes, you want to make sure to have the setting:

MaxBrushTypes = 100

If you are only using 10*2 brushes, then set it to 20 instead.


The fastest way to contact me for support is through my Twitter account:

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