Create time echo
create_time_echoApply echo trails, slit-scan, or per-pixel time displacement to a TouchDesigner TOP by building a container COMP with feedback and cache TOPs.
Instructions
EXPERIMENTAL — Apply a per-pixel time effect to a source TOP: echo trails, slit-scan, or per-pixel time displacement (the 'time machine' melt/slice look). Builds a container COMP that selects the source by absolute path (no cross-container wire) and then, by mode: echo — a feedbackTOP (wired input + forced resolution so the loop is not black) blended over the live frame at opacity=feedback to leave fading ghost trails; slit_scan — a cacheTOP buffering frames and a time-machine TOP reading different rows from different points in time; time_displace — the same cache read back through a luminance gradient (displace_top or a built-in vertical ramp) so bright pixels show older frames. The time-machine read operator is PROBED LIVE (timeMachineTOP → cacheSelectTOP fallback) because the optype name varies by TD build; the feedback opacity par (opacity → fadeval) and cache-depth par (cachesize → maxframes) are also set defensively. Every par/connect failure is collected as a warning and the chain still returns its output Null — UNVERIFIED across TD builds; tune live. Ends with a Null TOP 'out'.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| mode | No | echo: recursive feedback trails — each frame leaves a fading ghost (the classic 'echo trails' / time-blur look, driven by `feedback`). slit_scan: buffer N frames in a cache and read different rows from different points in time (rolling 'time slice' wipe). time_displace: per-pixel time offset driven by a gradient (`displace_top`) — bright pixels show older frames, dark show newer (the 'time_machine' melt/warp). slit_scan and time_displace both buffer frames in a cacheTOP and read them back with a time-machine TOP. | echo |
| name | No | Base name for the container COMP that holds the chain. | time_echo |
| frames | No | Buffer depth / cache size in frames for slit_scan and time_displace (how far back in time pixels can be pulled). Ignored in echo mode (feedback is recursive, not frame-indexed). Larger = longer time range but more GPU memory. | |
| feedback | No | Echo trail strength [0–1] for echo mode — opacity of the fed-back previous frame blended over the current one. Higher = longer, more persistent trails (0.5 = balanced; 0.9+ = very smeary). Ignored in slit_scan / time_displace. | |
| resolution | No | Forced output resolution [width, height] in pixels. A fixed resolution is REQUIRED for the feedback path (echo mode) so the loop has a stable frame from cook 0 and does not stay black. | |
| source_top | Yes | Path of the input TOP to apply the time effect to (e.g. '/project1/moviefilein1' or a Null TOP). REQUIRED. | |
| parent_path | No | Where to build the time-echo chain (a COMP path, e.g. '/project1'). | /project1 |
| displace_top | No | time_displace mode only: path of a TOP whose luminance maps each pixel to a time offset (a gradient/ramp/noise — bright = further back in time). Omit to use a built-in vertical ramp (rampTOP) so the effect works out of the box. Ignored in echo / slit_scan. |