# Color coding

This modifier assigns colors to particles, bonds, or arrows based on one of their properties. It thus provides a simple method to visualize scalar per-particle or per-bond quantities.

The values of the selected input property are first mapped and clamped to the unit interval [0,1] according to the Start value and End value parameters of the modifier. The normalized values are then mapped to a color using the selected color gradient map and finally assigned to the particles or bonds.

The Adjust range button resets the Start value and End value parameters to the minimum and maximum value of the selected input property, respectively. This ensures that no clamping occurs when property values are mapped to colors. The Adjust range (all frames) button does the same but considers every frame of the animation sequence when determining the range of values, not just the currently loaded frame. The Reverse range button swaps the Start value and End value parameters to effectively reverse the color scale.

## Custom color maps

The modifier provides a set of predefined color maps that you can choose from. If you want to define your own color scale, select Load custom color map... from the gradient list box. The program will then ask you to pick an image file which contains the colors of you custom color map. With this feature you can import arbitrary color maps into OVITO by preparing a corresponding image with an external image editor. OVITO uses the colors along one row of pixels of the image to generate a user-defined color map. Here are two example color map images:

## Color legend

You can insert a color legend into rendered images and videos by adding a Color legend overlay to the active viewport.

## Parameters

Operate on

  Controls whether the modifier assigns colors to particles, bonds or vector arrows.

Property

  The input particle property or bond property to be used for color mapping.

Color gradient

  Selects the color gradient for mapping scalar values to colors.

Start & end value

  Controls the value range for the linear mapping of input values to the [0,1] interval.

Color only selected particles/bonds

  This option restricts the assignment of colors to currently selected particles or bonds. The colors of unselected particles or bonds will remain unchanged.

Keep selection

  OVITO uses a red color by default to highlight selected particles in the interactive viewports. Since this highlighting would mask the actual colors assigned by this modifier, the modifier clears the current selection by default. If you want to preserve the selection, because you want to use it further down the data pipeline, activate this option.