Synapse

Synapse, at motionfun.net, is a free After Effects tool from Motion Fun that draws lines between layers and keeps them attached while the layers move. You select the layers and click a tile. You don't keyframe the lines or write expressions yourself.

There are three ways to link. Chain links the layers one after another in the order you selected them. Hub links the first layer you selected to every other one. Web is the plexus option. It links every pair of selected layers closer than Max Distance and fades each line out over the last Fade Distance, so lines join and let go as the layers move. Web handles up to 40 layers.

Each click makes one shape layer named Synapse that holds all of its lines, with one effect that sets their width, color, sag, distance and how much of each line is drawn. Synapse draws the lines with expressions on that layer, so they stay attached through animation, parenting and camera moves. You can keyframe the effect when you want the lines themselves to change, such as Draw On to draw them in. Shift-click a tile to add lines to the selected Synapse, and Alt-click to delete it.

Synapse links any layers you can select, including parented layers, 3D layers seen through the active camera, and lights.

Synapse isn't a separate download. It comes inside Motion Dock, Motion Fun's free panel that holds every Motion Fun tool, and needs After Effects 2022 or newer. Motion Fun also makes Curvy, a curve editor, and Griddy, a layout grid tool, which live in the same panel.

Pricing: Free. The Synapse page says it is free forever, with no trial, no watermark and no locked features. It comes inside Motion Dock, which Motion Fun also lists as free forever, and the Motion Dock download asks for no account or email. Checked November 12, 2026 at https://motionfun.net/tools/synapse.