Sleep is vital to life, though transhumans don't need as much of it. Basic Biomods reduces the amount of sleep vs active period, and Circadian Regulation does so further. But, mods like Hibernate allow one to sleep deeply longer. Even though Synthmorphs do not require to sleep, many sleeved in them will use low-power modes to take breaks to rest the mind and kill time. Infomorphs can slow run time and emulate sleeping mind states to rest and refocus. As biological importance is retained, so is cultural importance - which can lead to interesting junctures between culture and technology.
Simulspace and VR in general are amazing tools. There are entire subcultures who chose to live not only as infomorphs but in VR environments permanently. They can simply exist in VR sensorium servers and persist there so long as the server operates. For those outside, Simulspace is a bit different, and for biomorphs accessing VR is usually done through a headset with a hardline connection which manages brainwave data - allowing the replacement and immersion in the new sensorium. VR is usually accessed in special couches, beds or chairs to keep the body relaxed and prevent harm from any additional movements in the real world. This also means it provides a relaxing space where transhumans might feel able to sleep. This juncture is the origin point of Dreamweavers.
The art or science of dreamweaving is part psychosurgery, part simulspace engineering, and a bit classical psychology. Those with a more technical aptitude might apply neurology directly also. It is possible to engage in Simulspace while asleep or mimic a sleeping state with the technology. While most people engage with it while fully conscious, the interface point itself doesn't necessarily care. However, interacting with VR while your brain is in various states of rest is difficult and complex, limited often to those who have the ability to lucid dream. This is where a good Dreamweaver comes in. Someone with the technical and academic skills to oversee a dreamer and manage both their psyche and the software and hardware it is working with. The profession is a bit fringe in some habs, especially with a more conservative view on technology, but is non-invasive and entertaining or even therapeutic, so it's not uncommon to be able to find one on the Mesh.
A Dreamweaver can perform many services and operations, and usually does so in real space from a very close proximity to the dreamer - though with decent connection they can operate remotely. Because they have access to both a sleeping mind and body, intense trust is needed with a Dreamweaver. This can sometimes lead to intimate relationships between the dreamer and the weaver. The most simplistic option with a 'weaver is for them to record naturally occurring dreams not just as XP (which some people do as a form of "dream journal") but render them in fully interactive VR. This can allow for interactive dream analysis, editing and even "resumption" of a dream which ended or drifted away originally. The more common and complex option is real time dream observation, editing and suppression. Originally devised as a therapy for those with night terrors and other issues, this process has a Dreamweaver observe dreams (as the sleeper perceives them) and use their VR interface to alter the direction or content of the dream. Traumatic nightmares might be gently brightened or ended to shift to a new dream, stress dreams can be de-stressed and dull dreams might be made more interesting. Because this is done in real time, it requires some skill to string together the hybrid of VR programming and psychosurgery commands to shift dreams on the fly - and poor cohesion or design of a dream edit can cause undue stress on the subject - causing them to wake up. Dreamweavers tend to get better at this the more they work with a client (as the process also often helps with insight and psychotherapy as well) and can learn to navigate their particular dreamscape - which promotes long relationships with a good 'weaver.
The most complex service of Dreamweaving is also the best known and most popular. Not only can they record and interact with normal dreams, but via the Simulspace interface a good 'weaver can take over for normal subconscious dreaming patterns and induce specific dreams in the subject. Because of elements of sub- or unconscious interaction with the dream-state, Dreamweavers who actually build dreams often say that they must remain flexible in their design and often made changes on the fly to the program to account for an active dreamer. In these cases, the client tends to "order" certain dreams or themes before they go to sleep, and the 'weaver executes on them, using their knowledge of the dreamer and their own library of software to bring about the desired result. This is not quite the same as utilizing VR normally, while some dreamers (and particularly good Dreamweavers) can induce lucidity in these dreams they aren't fully immersive or interactive like a normal simulspace - they behave more like natural dreams which content or themes have been "pre-picked" by the dreamer and implemented by the 'weaver. Some Dreamweavers make the dreams in real time as the sleeper experiences and reacts to them. Others can implement pre-programmed dream types, and edit them to match the sleeper's personality. Inducing a dream must be done very carefully to avoid causing undue mental stress on the subject. Additionally, being too loose with the controls on a dream can cause the natural sleeper's mind to influence it causing it to go "off script".
It still is a very popular service by those with good money to engineer their dreams, often hiring personal dreamweavers like one patrons any art - or high quality dreamweavers drawing large packs of clientele like a famous surgeon or therapist. Economically, Dreamweaving isn't as strong in the New Economy, as on just pure Reputation it can sometimes be difficult to organize appointments and clients when they are all in good standing in the community - leading to a handful to operate on "first come, first served" basis or involve trading of favors directly. Usually, you find people with the talents exclusively offering it for therapeutic benefits to a broader community, or where Networking can get you an introduction to a 'weaver, who then screens for people they are particularly interested in working with (though being too exclusive can harm one's own reputation). Also very common is that Dreamweavers form small communities and groups who train and practice together, and will offer services to friends and close companions, or work together to handle scheduling in other people from outside the collective to come in and experience their craft, which enhances the reputation of the collective.
Should the mechanical need to model Dreamweaving come up, the simplest way is to treat it as a specific Specialization of a skill like Programming or Art: Simulspace Design, and have the 'weaver roll that skill as a Task Action which last however long the subject sleeps (and probably shouldn't operate under normal speed reduction, unless you want to wake the subject up early). Success means the dream is woven as it should be, and failure means things didn't quite go as planned. On Critical or Excellent success, the subject might even heal a few points of Stress, but conversely on Severe or Critical failures a particularly "bad trip" should probably inflict some stress.
Or, if you want to get more technical, treat it like a Psychosurgery proceedure (which Programming or Art: Simulspace Design might complement). It has a timeframe of however long the subject is asleep (average 4-8 hours), with a modifier of +20 if you're just suppressing or editing normal dreams, and +0 if you're weaving a dream completely. Oppose with WILx3 as normal. If the surgeon succeeds, things go off perfectly, and if they have a good MoS the subject might heal some Stress or gain some other temporary benefit. If both pass, then the dreamer's subconscious (or conscious if they can lucid dream) may take the dream in unexpected directions - the result is an interesting and memorable experience, but no long term gain. If the surgeon fails or the subject rolls higher on their WIL test, their subconscious rejects or persists in its natural dreams, and the dreamer takes 1 SV (more maybe, if the PS fails worse) and if they pass the WIL test probably wake up in the middle of their sleep.
Additionally, a character who performs dreamweaving services for someone should get a hefty bonus to rolls like Kinesics or Psychology aimed at determining that person's mood, mental state or attitude to the tune of +10-20 as they have a very good look at what the subject's subconscious is like.
Not all applications of technology are good, and not everybody who delves into the world of Dreamweaving is interested in helping others - they have more selfish goals in mind. These people who range from antisocial at the best to psycho-criminals as worst are usually called "Dream-Eaters". At their lowest level, Dream-Eaters are voyeuristic and opportunistic. Instead of steadfastly watching over and guiding another's dreams, they might hijack their dream-state for their own amusement, or even utilize XP or VR to experience the dreams they make through another person's POV. Others may copy XP or VR data of dreams without permission, and share or sell them to others (sometimes unedited) in place of their own work. Some Dream-Eaters are con artists, who use the physical proximity and vulnerability of the subject for personal gain - or engage in a tactic known as "inception", where they plant careful triggers or cues in the sleeper's dreams to engage in social engineering. Some may utilize the data gathered on a sleeper's psyche for blackmail or emotional manipulation - while more insidious operators will use their access to a person's Ego and Morph to perform unauthorized psychosurgery or forking of the subject.
These criminals are potent and dangerous, and may be solo operators or associated with big outfits like the ID Crew or Nine Lives. Their actions can be motivated by simple greed to profit off others, or they may have more antisocial or disruptive behaviors in mind. Dream-Eater schemes are often hard to catch without another 'weaver to audit their work - but some get sloppy. Others get found out when people close to the victim realize something is unusual about their behavior or what they say their sessions are like. Due to the risks and damage such close access to a person can cause, the crimes performed by Dream-Eaters are usually treated harshly by most legal systems.