Light Effects panel

Every light effect builds on a user-defined color space: a one dimensional color ramp, a two dimensional color image or a custom function:

The light effect that you define in the panel produces one or two numbers between 0 and 1 for each drone, based on selected output mapping functions. The color ramp turns the first, the color image turns both mapped numbers into the color that gets applied to the drone.

Colors on the color ramp may have an alpha component. When the alpha component is 1, the color is opaque — it will replace the original color of the drone. When the alpha component is 0, the color is completely transparent and the original color of the drone will not be modified. Values in between 0 and 1 produce transparency effects — for instance, an alpha component of 0.5 mixes the original color of the drone with the color from the color ramp in equal proportions.

Light effects may be (and usually are) limited in space and time. Time-wise, the light effect affects the drones only from its designated start frame through its end frame. Space-wise, the light effect may affect all drones or only a subset of drones that are within the boundaries of an associated mesh. The mesh may be animated to produce dynamic light effects; for instance, you can "sweep" a cone of light on the drones by creating a light effect that sets the color of the drones to white, and then limiting it to the interior of an invisible sphere that is then swept through the scene.

You may have noticed that the upper part of the light effects panel is occupied by a list. This list contains the effects themselves. In each frame all the effects are processed in a top-down manner, and for each effect, Blender decides whether the effect is going to affect the current frame or not, depending on its temporal and spatial properties. In any given frame, multiple effects may be active, and in this case the original color of each drone (defined by the keyframes of its material) is modified by each active effect in the order defined by the list of effects. This becomes important when the colors of the effects have alpha channels as the output may be a mixture of the original color of the drone as well as one or more active effects.

Use the + button next to the light effect list to add a new light effect to the end of the list. You can remove effects from the list by pressing the - button. You can duplicate previously created light effects with the Duplicate Light Effect button. To rearrange light effects, use the ▲ and ▼ buttons.

Individual light effects can be enabled or disabled by clicking on the check box in front of the light effect. You can also give a descriptive name to each light effect by double-clicking on its slot to edit the name.

Use the Effect Type dropdown list to select a light effect based on a color ramp (this is the default setting). In this case, below the list of light effects there are standard Blender widgets to set up the color ramp associated to the currently selected effect in the light effect stack. These widgets work just like any other color ramp editor in Blender, but here is a short summary for sake of completeness:

Refer to the documentation of the Color ramp widget in Blender’s own documentation for more details.

Use the Effect Type dropdown list to select a light effect based on a color image. In this case an image selector input field appears where you can select the image used for the light effect. Further below a secondary output type selector and an optional output mapping selector also appears to be able to take advantage of both dimensions of the image as parametric input.

The most trivial usage of a color image is where e.g. the X axis represents time (TEMPORAL output type) and all pixel columns along the Y axis at a given X represent "discrete color ramps" for different time instants (e.g. using the 'INDEXED_BY_FORMATION' output type). This way color effect design is reduced back to simple color image design that can be performed with any external tool.

Another usage is to project a static image onto the drones in a grid formation, using the properly selected Gradient (…​) axis assignments on both axis.

Note that there is no interpolation between pixels in the color image, they are selected for each drone and each frame discretely. Therefore, color images should be used with a width/height that correspond to the selected output mapping perfectly (e.g. same height as the number of drones, same width as the number of frames in the light effect etc.), or they are suggested to be smooth images without sharp edges to compensate for the rounding errors of the discrete mapping. You can also scale up a low-resolution image in an external image editor tool and use the scaled-up version to simulate interpolation.

Use the Effect Type dropdown list to select a light effect based on a custom function. In this case a file can be selected that contains the Python function that will be used as the custom function for the light effect. The file should contain a Python function with the following named arguments:

The next group of widgets below the color ramp or color image specify the temporal constraints of the light effect, i.e. when the light effect should be applied. The two hard limits are the start frame and the duration: the light effect will be completely inactive outside this time interval. The fade in and fade out widgets specify the duration of the fade-in and the fade-out periods at the beginning and the end of the time interval of the light effect. During the fade-in period, the intensity of the light effect grows gradually from zero (inactive) to 1 (fully active). Similarly, the fade-out period animates the intensity of the light effect from 1 (fully active) to 0 (inactive). You can turn both of these off by setting their duration to zero.

Light effects may also be limited in space such that it affects only a subset of the drones. This is achieved by selecting a mesh in the Mesh picker widget and then setting the Target dropdown to one of the following options (instead of "All drones", which does not create a spatial constraint):

The result of the spatial constraint can also be inverted with the Invert target checkbox. This is mostly useful in conjunction with the Inside the mesh option, allowing you to match only those drones that are outside the associated mesh instead of being inside.

The Output X and Output Y dropdowns determine how the color of a drone is picked from the color ramp or color image. Recall that each light effect essentially produces one or two numbers between 0 and 1 for each drone, and then passes this number through the color ramp or color image to calculate the final color that the effect will apply on the drone. The output dropdowns provide options for picking this number:

Some output mode types (such as Distance from mesh and Gradient-based types) support two mapping modes between the drones and the color ramp:

The Influence parameter sets the overall transparency of the light effect. 1 means that the light effect completely overwrites the base color animation, 0 means no effect at all.

The Randomness parameter can be used to add a bit of randomness to the numbers picked by the drones according to the Output dropdowns. Each drone is associated with a unique random number between -0.5 and 0.5, this number is multiplied by the randomness parameter, wrapping around the edges of the color ramp or image as needed, and the result is added to the number that was calculated based on the setting of the Output dropdowns. This final number is then used to pick the color of the drone from the color ramp or image. Note that the default value of the randomness parameter is zero, which means that the value derived from the Output settings is used as is.