The Flame filter is a complex rendering tool in the Nature menu. There are many available options which will affect the result.
The top left area of the Flame window shows a preview pane. Any changes made to the Flame settings will be displayed here.
Clicking the Edit Flame button will provide an options window. Displayed are nine versions of the Flame. The center version represents the current flame. The surrounding eight neighbors represent the alternates based on the Controls located below the nine previews. Clicking the center image will regenerate the surrounding flame previews using the same mathematics as the center flame. Clicking any of the other eight will move the selected flame into the center, and re-render the surrounding flames using the new center flame as the base.
Controls gives control over the actual flame render. This is achieved through three settings.
Speed affects the mathematical velocity of the flame render. This setting can be changed with either the slider or the input box.
Randomize randomizes the creation method of the flame. Clicking this button will produce totally random results.
Variation provides a drop-box with a choice of mathematical algorithms. It is beyond the scope of this document to describe the mathematics involved here, but many users with a pure math background will understand this.
The Rendering options section of the main Flame dialog window provide many post-render settings.
Brightness controls the overall brightness of the flame render.
Contrast sets the contrast of the render. A higher contrast will result in a sharper render at the expense of color information.
Gamma adjusts the gamma of the render.
Sample Density controls the amount of render detail used. A higher setting here will produce a more detailed render. A lower setting will utilize fewer pixels to describe the flame.
Spatial Oversample When this is activated, the effect is calculated on a grid smaller than pixel size and then resampled for display. This does not appear to be activated yet in this filter.
Spatial Filter Radius determines the amount of blur filtering that will be rendered with the flame. A higher setting will result in a blurred flame.
Colormap sets the color gradient that will be used with the flame render. This setting changes the color map that colors the final render. Clicking the name of the currently selected color map will allow changes to be made here. Gradients, Layers, and Images can be used as valid color maps.
The Camera settings affect the visual rendering of the flame artifact. Zoom changes the visual closeness to the flame. Valid settings are between -4.00 and +4.00. X and Y change the position of the flame on the X and Y axis.