Gradients are used at many locations in Cinema 4D and make it possible to use color and alpha values to create linear gradients that run from left to right. Various types of interpolation are available, which can also be used to calculate automatic transitions between the colors and alpha values you have placed. Note that you can access further parameters (described below) by clicking on the small arrow to the right of the color gradient.

The small, square color fields directly below the gradient (called Knots) determine the colors and their positions in the gradient. To add a new Knot, simply place your mouse pointer just below the gradient. A semi-transparent color tab appears, which can be moved sideways together with the mouse pointer. A click then creates a new color tab. To remove excess color tabs from the gradient, simply drag them up or down out of the gradient with the mouse.
To change the color of a color tab, select it by simply clicking on it. Below the gradient, settings for the exact position of this color on the gradient, the interpolation used on this tab to the neighboring color on the left and, of course, the standard color sliders for adjusting the color are displayed. Some interpolation types also offer additional Knots on the gradient, which are visible as small circles between the color tabs. This can be used to change the mixing point at the color transition between the colors. These Bias Handles can also be moved directly with the mouse or placed with numerical precision by simply clicking on a numerical value for the bias position.

If you also hold the Shift key when moving color, alpha or Bias Handles, the movement will be performed in 5% increments.

Several Knots can also be selected at the same time. To do this, you can select the Knots one after the other using Shift + click (or remove them from the selection again using Ctrl-click) or hold down the left mouse button directly in the color gradient and drag a selection frame over the desired Knots from there. Orange brackets appear around the selected Knots below the gradient. All Knots contained in such a bracket can be moved together along the course if you place the mouse pointer between the brackets and then drag them with the left mouse button held down. Pulling on the Knots will scale the distances between the Knots within the brackets. The colors cannot be placed outside the boundaries of the gradient. If you move a group of color tabs too far to the left or right, the outer color tabs will automatically stop at the edges of the gradient and their distance to the subsequent colors may be reduced as a result.
Similarly, the bias Knots can be selected in groups and then moved together. However, no separate Knot symbols will be displayed. Selected Bias Handles can be recognized by the black coloring, whereas unselected Knots use a white circle as a symbol.

A double-click in the color gradient selected all Knots, a single click deselects everything. Double-click on a Knot to display all settings in a separate window. If there are several Knots on top of each other, they can be right-clicked to select one of them from a list that appears (selected Knots are enclosed in square brackets).

The gradient can be moved or scaled horizontally (see below). In the latter case, brackets appear around the color gradient (red marking at the top of the image). Clicking on these brackets scales the color gradient back to 100%.

Selected Knots can also be moved using the cursor keys (left, right). Shift also quantizes in 5% steps here. The cursor up and down keys adjust the Knot brightness (old color gradient only).

The following buttons apply for navigation within the color gradient - similar to the Timeline:

• 1, Middle mouse button: Move (only possible with enlarged color gradient)
• 2, Mouse wheel, Alt + right mouse button: zoom in and out
• S: Show selected
• H: Show all or scale to 100%.

Right-click on the color gradient to open a context menu with the following commands:

Invert Gradient

This reverses the color gradient and thus the order of the colors.

Double Knots

This defines the current color gradient to its own end, doubling the Knots and the color gradient.

Distribute Knots

This sets the Knot distances to identical values.

Bias Handle

If Bias Handles (the small circles in the color gradient) are to be displayed, this option must be activated.

Interpolation of all Knots

This lets you set the interpolation of ALL Knots - regardless of the selection - at the same time.

Size

This can be used to define the vertical size of the color gradient in 3 stages. This setting is also available as a program default setting (Units tab).

Interpolation

Several interpolation methods are available to control the behavior of the color values between the Knots. Each Knot can have its own interpolation!

Soft/Cubic/Cubic Bias/Linear/Step/Blend

The color transition from one selected Knot to the next takes place as indicated by the small curve symbols in front of each option. Most interpolation types also use the Bias Handles to place the color transition between the adjacent colors as desired. Only with Step interpolation will there be no Bias Handles, as the color change will always take place abruptly when the next color Knot to the right is reached.

Step

There is no interpolation at all. The color changes abruptly without transition at the position of the next touch.

Knot position

The position of selected Knots can be defined numerically here. 0% = left edge, 100% = right edge.

Bias position

This parameter defines the position of selected Bias Handles between the adjacent colors. 0% = left color or alpha Knot, 100% = right color or alpha Knot.

Brightness

Brightness can also be used to control the brightness of selected Knots above 100%. They generate overbright colors (HDR) that the color selector cannot provide on its own.

Edit Alpha

Activate this option to work on the alpha values associated with the color gradient. The creation, placement and setting are carried out in the same way as already described for the color Knots. The only difference is that only percentage values and therefore no colors can be assigned for the alpha Knots via a Brightness value. The curve interprets 0% as black and 100% as white. Values between 0% and 100% are often used here by default, but brightness values above 100% can also be assigned.
The alpha Knots can be placed completely independently of the colors. Therefore, all color Knots and their gradients are also hidden by default in this mode.

Display Result

This option displays the color gradient taking the alpha channel into account. This means you can practically display the opacity of the alpha Knots overlaid with the colors while you work on the placement and values of the alpha Knots.

Load Preset

Save Preset

Color gradients can be saved and reloaded at any time using these two commands.

When the Save Preset command is executed, a small dialog window will open where the preset name and other information can be entered.

Click on Load Preset to open a small selection window where you can load the corresponding preset with a single click. There you will already find a selection of common color gradients, even if you have not yet saved your own.

General details regarding the Preset System in Cinema 4D can be found there.