Editing Stargate (device) (section)

== Making of the props ==
Two full Stargate [[Theatrical properties|prop]]s were originally built for the ''SG-1'' pilot "[[Children of the Gods (Stargate SG-1)|Children of the Gods]]", the second of which was reconstructed from the prop used in the [[Stargate (film)|film]]. They are made of steel and [[fiberglass]], and are {{convert|22|ft|m}} in diameter. The second prop is less detailed, and is used for exterior scenes; in the pilot it was used solely on the planet Chulak. The primary one is fully automated and capable of rotating and emitting light. This is achieved by the use of a specially designed {{convert|22|ft|m|adj=on}} circular [[gear]], which turns the inner ring on a precise [[pinion]] drive wheel, using an eight [[horsepower]] electric motor. The top seven chevrons emit [[laser]] pulses that are read by a sensor fed into a computer responsible for the gate's movement, which is consequently able to start and stop the rotation very quickly. This main prop is kept almost immovably at the permanent set of the [[Stargate Command|SGC]], at Bridge Studios, [[Vancouver]].<ref name="prod">{{cite web|url=http://www.rdanderson.com/stargate/productn/productn.htm|title=Production notes for ''Stargate SG-1''|work=[[Richard Dean Anderson]] Official Website|url-status=dead|archive-url=https://web.archive.org/web/20060427125501/http://rdanderson.com/stargate/productn/productn.htm|archive-date=April 27, 2006|df=mdy-all}}</ref>

There are further Stargate props that are no more than two-dimensional or semi-three-dimensional (jar-lid shaped) Stargates, being more lightweight and easier to erect on location. These are always filmed front-on to preserve the illusion. If a shot involves the [[Iris (Stargate)|iris]], this is added in post-production, as the mechanics of it opening and closing would be very difficult to build. However, when a Stargate is filmed with just a closed iris (i.e. without it moving), a tangible prop is inserted into place.{{citation needed|date=November 2022}}

The visual effects for ''Stargate SG-1'' and ''Stargate Atlantis'' are predominantly produced by [[Rainmaker Digital Effects]], a notable visual-effects studio. However, some effects, including the entire Ori battle sequence in the episode "[[Camelot (Stargate SG-1)|Camelot]]", were done "in-house".<ref name="brad">{{cite web|url=https://gateworld.net/news/2006/07/wright-on-target/|title=Wright on target: An Interview With Brad Wright|work=[[GateWorld]]|date=July 3, 2006|access-date=November 27, 2020}}</ref> The unstable vortex effect, both in the film and the early seasons of the series, on account of being "difficult to achieve" was generated only once and recorded from various angles; this recording was the same used for all gate opening shots early in the series.<ref name="prod"/> Rather than being a jet of water, it is actually the image of high-pressure air being blasted ''into'' a tank of water. The effect was achieved by mounting a jet airplane engine two feet above a water tank, and using its {{convert|180|mi/h|km/h|abbr=on}} windstream to create the sufficient water displacement. In post production, the surrounding water was removed with computer editing, and the image of the air-jet pasted into the center of the opening stargate. This technique was only used for earlier episodes, and the effect was replicated digitally soon after to allow more flexibility in shots.

To cut down on costs, the opening of a Stargate is often just ''implied'' rather than shown, by a costless sound-effect followed by distinct lighting effects characteristic of light shining through water (as the event horizon is depicted). The [[Stargate SG-1 DVD|DVD]] commentary for ''Stargate SG-1'' explains that these effects are produced by reflecting light off large sheets of vibrating [[Mylar]].

[[Image:Pegasus-gate.jpg|thumb|An orbital Stargate in the Pegasus galaxy, with 3 station-keeping rocket packs attached evenly around the rim]]
The Stargate itself is nearly always filmed against a [[Chroma key|blue or green]] backdrop, not only making it easier to paste the vortex imagery onto the scene, but also facilitating the superimposition of the "event horizon ripple effect", which is entirely [[computer-generated imagery|computer-generated]]. However, if a shot only involves an open wormhole without anyone stepping through it, the crew may choose to use a "practical puddle," which is simply a backlit screen placed in the gate displaying a video of the wormhole effect. This only works, however, on a darker set, as otherwise the projection will get washed out.<ref>{{cite episode|title=The Pegasus Project (DVD Commentary)|episode-link=The Pegasus Project (Stargate SG-1)|series=Stargate SG-1|series-link=Stargate SG-1|airdate=July 28, 2006|season=10|number=3}}</ref> On occasion, the Stargate itself is also completely swapped out for a computer generated model, usually in cases where it is being moved, or is depicted in space. Series producer [[Robert C. Cooper]] explained that it often costs a lot to erect a Stargate on location, and so in some cases offworld gates are also entirely a visual effect.<ref>{{cite web|url=https://gateworld.net/news/2006/04/directing-the-future/|title=Directing the Future: An Interview With Robert C. Cooper|work=[[GateWorld]]|date=April 14, 2006|access-date=November 27, 2020}}</ref>