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Input and output triggers in Dragonframe
Dragonframe / DMX lighting control in Dragonframe (DDMX-512)
Definition
Dragonframe's triggers connect the capture cycle to equipment outside the camera. Through one of DZED's controllers (DDMX-512, DDMX-S2, DMC-32, DMC-16, DMC+ or IOTA), an external input such as a push button or a motion-control system can tell Dragonframe to shoot a frame, start or stop playback, or run its DMX lighting program. In the other direction, Dragonframe can close a relay or set a logic-level signal at chosen points in each frame's capture. That lets it fire an unsupported camera, switch a bash light, or cue an external go-motion move.
Overview
A stop-motion frame is a short sequence of events rather than a single moment. Dragonframe first grabs a video-assist image from live view, then readies the camera, takes the high-resolution still, and may repeat that for several exposures. Other equipment on the stage often has to act at a particular point in that sequence. Dragonframe's Scene > Triggers dialog turns those points into electrical signals. It needs one of DZED's controllers: the DDMX-512, DDMX-S2, DMC-32, DMC-16, DMC+ or IOTA. The manual writes its instructions for the DDMX-512 but says they hold for all of them.
The input side is the simpler one. A device wired to the controller's logic input (the IN and GND terminals) can trigger one of three Dragonframe events: SHOOT, PLAY/STOP, or REAL-TIME DMX PLAYBACK. The manual's example is a push button that shoots a frame when pressed. An external motion-control system can drive the same input. Our reading: a hardware shoot button wired this way lets the animator take a frame without going back to the keyboard or keypad.
On the output side there are two kinds of signal. A switch/relay output (the RELAY terminal) closes a contact. A logic output (the LO or HI and GND terminals) sets a logic level. Either one can fire on any of these events: when SHOOT is pressed; after the video assist is captured; after the high-res frame is captured; after all of a frame's exposures are done; for as long as a frame is being captured; or whenever a work light should be on. It can also be programmed as a trigger channel in the DMX workspace. A hold time sets how long the signal stays active. The same mechanism can fire a camera Dragonframe does not support: SHOOT closes a switch, and the camera takes the picture. On the DMC-16, DMC+, DDMX-512 and DDMX-S2, HI and LO come from one output and are inverses of each other. The DMC-32 instead gives two separate +5 V signals that are normally low.
The "work light" event solves an old continuity problem. Animators want a bright bash light on while they work and check live view, but it must be off for the frame that is actually shot. With the light wired through a relay or the logic output, Dragonframe keeps it on during video assist and turns it off for the high-res capture. It does this without a DMX dimmer pack (compare lighting-continuity and live-view-vs-high-resolution-capture).
The most precise use is go-motion with an external motion-control rig such as Kuper or Flair. With go-motion timing enabled, each capture runs in a fixed order. Dragonframe takes the video assist, readies the camera, and fires the after-video-assist trigger so the rig starts its move. It then waits a pre-roll time and captures the high-res frame while the puppet or camera is still moving, so the blur lands on the frame. In DZED's tests with Kuper, the formula pre-roll = (exposure time / 2) + 0.15 s gave repeatable blur. Kuper's exposure was set to twice the camera's, because Kuper was designed for film cameras, where the film is exposed for half the exposure time. A 1-second shutter therefore pairs with a 2-second Kuper exposure and a 0.65-second pre-roll. These steps apply only to external systems: the DMC-32, DMC-16, DMC+ and DFMoco-based devices perform go-motion themselves. They also have a 3-pin camera trigger whose meter (pre-shutter) and shutter signals can be tested from the same dialog on the newer Zynq-based boards. That includes every DMC-32 and the upgraded zDMC-16 and zDMC+.
Workflow
- Connect a DZED controller (DDMX-512, DDMX-S2, DMC-32, DMC-16, DMC+ or IOTA) to the capture computer, as described in Dragonframe's 'Connecting DMX to Dragonframe' section.
- Wire the external device to the right terminal: IN and GND for an input such as a push button; RELAY for a switch closure; LO or HI and GND for a logic level.
- Open SCENE > TRIGGERS.
- For an input, choose the event it fires: SHOOT, PLAY/STOP or REAL-TIME DMX PLAYBACK.
- For an output, choose the moment it fires: on SHOOT, after video assist, after the high-res frame, after all exposures, while capturing, or when a work light should be on. You can also program it as a trigger channel in the DMX workspace.
- Set the hold time, then shoot test frames to confirm that the light, camera or rig responds on the intended event.
- For go-motion with an external rig such as Kuper or Flair, use the after-video-assist trigger and enable go-motion timing. Set the pre-roll to roughly half the exposure time plus 0.15 s, with the rig's exposure set to twice the camera's. Then check the blur on test frames.