D&D sci-fi setting?

[RotGrub]

cool I'm really liking Eclipse Phase.

 

[Thomas Bowman]

That is very close to what I had in mind. Except, they are living on an artificial Dyson Swarm created by beings that have long since perished (or evolved themselves via a singularity). In ages past, Earth like planets in the system that once harbored life were completely consumed/destroyed to create the Dyson Swarm.

In the current age, life is completely artificial in nature. Creatures range from old crude robots to complex artificial cellular forms of life.

One thought I had was that a major faction of artificials would be completely under the control of the "mother brain". Other factions, living in the wild zones would oppose this oppressive entity to variing degrees. And one dangerous faction in particular would seek to steal the secret of biological life, which they believe the mother brain is withholding.

The PCs would be stuck in the middle of this conflict. They would have to avoid being connected "to the brain" (think Borg) at all costs. They might even quest to destroy her, to free millions of oppressed artificials or even start of a new genesis. At some point, during the campaign, they would be given the option to transfer their minds into biological life forms. It's a sci-fi Pinocchio story of sorts, but think it will work out well.

When the PCs start, I might have them make standard characters and races. Of course, when they wake up as an artifical dwarf, an artifical human, etc.

With that said, I still want everything to feel medieval. No guns, but high sci-fi weapons and magic will be available.

But yes, PCs might wonder if their world is some sort of westworld simulation, but that's not my problem

oh and Transformers is certainly an inspiration.

One thing I have been thinking about are the environmental challenges robots would have. A desert might cause serious issues with overheating, dust, etc. Water might be completely disabling. Rust would be another issue.
Food would be some sort of energon and/or solar energy. I'm not sure what an energon farm looks like, but I'm sure I could tweak a medieval robot society a bit.

How about something like the Matrix? A simulated world and then a real world, or how about a whole bunch of simulated worlds contained within the shell of a Dyson Sphere, and I know just the sort of star to build a Dyson Sphere around. Ever hear of Gamma Crux? It is the closest red giant star to our Sun, it is located in the constellation known as the "southern cross."

Gacrux has a stellar classification M3.5 III.[3] It has evolved off of the main sequence to become a red giant star, but is most likely on the red giant branch rather than the asymptotic giant branch.[7] Although only 30% more massive than the Sun,[6] at this stage the star has expanded to 84[7] times the Sun's radius. It is radiating roughly 820[8] times the luminosity of the Sun from its expanded outer envelope. With an effective temperature of 3,626 K,[9] the colour of Gamma Crucis is a prominent reddish-orange, well in keeping with its spectral classification. It is a semi-regular variable with multiple periods.[3] (See table at left.)

https://en.wikipedia.org/wiki/Gamma_Crucis
This star has some pretty important properties that would make building a Dyson Sphere around it easier than building one around our own Sun.
First thing is that it is 30% more massive than our Sun but 820 times as bright, that means that the habitable zone is much further out than our Sun, to find out how far out that would be, you take the square root of its luminosity 820, which is 28.6 times the distance of the Earth to the Sun A regular Dyson Sphere around our Sun would have a surface area equal to 500,000,000 Earths. Gamma crux can illuminate a sphere with 820 times that area at the same energy intensity as the surface of the Earth, the amount of area illuminated would be 410,000,000,000 times the surface area of the Earth, that number is also about the number of stars in our galaxy. You could simulate the inhabited portion of an entire galaxy, as you only have to simulate the parts where the people are! People within the simulation wouldn't know they are in a Dyson Sphere, they would have space ships and flit between stars, kind of like in Star Wars, and they would be none the wiser. To go outside, they would need android bodies.