Render Filters

Plasma noise

The plasma filter renders fractal noise.

You can set two colors to control the color of the noise. Click on the color boxes to the left to set a precise color.

Scale controls the overall size of the plasma noise, ranging from a random noise pattern, to large, puffy clouds.

Color model lets you select which color-space the clouds are rendered in, and this controls the overall color scheme and appearance of the clouds.

The mode drop-down control lets you blend the clouds with the image that was there before entering the filter. Modes are similar to layer modes, such as multiply, screen, etc.

The seamless button makes the clouds blend smoothly at the edges, to create a seamless, or tileable image.


Bumpy toy

The bumpy toy filter renders fractal noise, then applies a gradient to it. With this filter, you can create the appearance of things like clouds, marble, or stone.

There are 3 choices of algorithms, multi-perlin, spiky perlin, and recursive subdivision.  The first two are based on Perlin noise, and the third is the algorithm used for plasma.

Iterations controls how many times the noise is layered.  Each layer of noise has a different scale.

Displacing noise by itself can create interesting wave patterns in the noise.

A gradient swatch is provided so you can apply a color gradient to your noise pattern in order to create interesting effects.  Clicking on the swatch brings up the gradient editor.  You can also chose between any of the 8 gradients that are available at any one time.

The swap image can be used as a channel to control the value of the noise before it is passed through the gradient.  This can be used to create lighting or other effects.




Noises are a collection of fractal patterns that can be useful for the basis of other textures, or for various cloud effects.


Radiant allows you to create brilliant lens flares and reflections like those of a real cameras optical system. This is an older filter and is included for compatibility. The lens flare feature under the FX tool is easier to use and should be favored over Radiant, however, this feature does contain a number of powerful features.



The sky filter makes images of skies.

The sky color and fog color let you set the colors of the sky's apex and horizon.

The iterations slider determines how many layers of noise will be used to create the clouds.  Scale is the size of the clouds.  Phase is the relative scale of each layer of clouds.

Heading, Pitch, and bank lets you rotate the sky to suit your needs.

Zoom factor is the cameras zoom setting.

Cloud threshold is the level at which the noise used to make clouds becomes transparent to let the sky show through.  Cloud falloff level of how drastically the cloud edges become transparent.


Dread plating

The dread plating filter renders a spaceship hull texture. Weathering and scale can be controlled for greater variety.



The cellular filter renders a series of cells.  These can be used as the basis for other textures.  You can get a good water texture by inverting the image, or apply additional convolutions to get unique effects.

 Cell size, grid size, and cell count can be adjusted independently, but changing the Size slider adjusts these 3 parameters automatically for you.

Cell type can be Spherical, or Conical. If rendered in 3 dimensions, you would see that they are, in fact, 3d shapes.



This filter renders a checkerboard.  You have control over the colors of the checks, and over their size. The size can be adjusted independently for the x and y axis, or the two parameters can be linked together so the boxes are always square.

Click the color boxes to the left of the color swatches to make finer color adjustments.


The Europa filter renders a jagged, broken texture that may be reminiscent of the surface of the moon of Jupiter, Europa.

The filter is based on a series of lines that are rendered, and then blurred, and finally a gradient is applied to them to create the final result.

The filter is similar to fractal noise that is based on random points, except is based on random lines, a slightly more complex primitive, that may give more interesting results for certain textures.


Cold lava

This filter renders what appears to be a shaded stone texture.


RGB cube

This filter renders a slice of the RGB color space in rectangular form.


Brick texture

The brick texture renders a brick pattern that can form the basis for other textures (especially brick like textures.) You have control over the size of the brick and the mortar, as well as their colors.



This filter renders a star field.

Star size determines the relative size of the stars.  Their size will be somewhat random.  Distribution is the relative number of stars that will be rendered.

The red, green, and blue slider let you set the color of the stars.  The color will be slightly randomized for each star.


The woodgrain filter renders wood grain and other textures, such as sponges and camo patterns.


The grid filter renders a grid with variable line size and color.

Suppose you want to print a piece of graph paper with a grid size of one inch. You can use the “Other units” button to select a value of 1 inch, and match the DPI (dots per inch) to that of your printer.


The Zrings filter renders a marble like pattern of concentric rings.

Frequency controls how close together the rings are and how wide they appear. Displacement controls how much the rings are displaced by a noise pattern to create a more random, organic (or mineral) pattern. Noise scale is the size of the noise pattern that displaces the rings.


The Mandelbrot filter renders the mathematical phenomenon known as the Mandelbrot set. You can zoom into the Mandelbrot to a very high degree. Click and scroll inside the preview area to locate the area you want to zoom in on.

Depth and Preview depth controls the number of times the Mandelbrot is calculated. A higher value means a higher precision, but also takes longer. Therefore, you can use an smaller value for previewing, and a larger value for the final render.

You can apply a different gradient to the Mandelbrot to get different looks. You can also stack up layers of Mandelbrots to get more complex patterns. A new layer is added each time you click on the “Add layer” button, and you will be prompted for a layer mode to select.

A button is provided to merge layers at any time, or you can do it from the layers panel after you exit the filter.

The Mandelbrot can also be animated. You can set a zoom speed, and watch as the camera zooms into the Mandelbrot.

If available, your GPU will be utilized to speed up rendering.


The triangles filter serves as a demonstration of Howlers low level 3D API's polygon and sphere rendering routines. You may also find various creative uses for them.

The filter will give a good idea of how fast the 3D routines can render polygons, but there is some slowdown due to having to display them on screen. They screen is refreshed once every 10 polygons.


The Gems filter renders a pattern that resembles sharp and craggy stones, similar to a surface covered with cut gemstones.

You can control the size of the gemstones, and give the shapes some variance with the Subscale property.

Gems makes an excellent starting pattern for other filters, such as the lighting filter, or the Puppyray raytracer.