According to FutureTimeline.net, A Dyson sphere could be built around the solar system around the year 3100 when the world reach the Kardashev type 2 scale. This is what is written there about the issue:
Humanity is becoming a Type 2 civilisation on the Kardashev scale
The exponential growth of AI has allowed the manipulation of matter on scales barely dreamed of before. The largest structure now being built in space is a "Dyson Sphere".* This hollow shell is of such gargantuan proportions that its radius stretches from the Sun to beyond the orbit of Jupiter.
Under the direction of a Godlike superintelligence, vast swarms of automated, self-replicating ships are building it, using material from the asteroid field, Kuiper Belt and Oort Cloud.
The sphere's primary purpose is to harvest literally all of the energy output from the Sun: some 386 yottajoules (YJ) per second.* However, it also serves the function of shielding our inner solar system from gamma rays and other incoming hazards. Even the potential possibility of alien invasion has been taken into consideration during the sphere's design.
The interior walls have a gravitational field of 1G and are made from wholly new states of matter that were unknown to science in previous centuries. These can withstand the colossal tensile forces required to maintain structural integrity. This curved, impossibly large surface – equivalent to billions of planet Earths – is becoming a habitat for many sentient lifeforms, with portions being terraformed and given stable atmospheres, oceans and landmass. A sizeable percentage of citizens are now migrating to these strange artificial worlds. This includes a diverse mix of biological humans, as well as transhumans, synthetics, clones, androids, sentient animals and other communities. A series of additional Dyson Spheres are being constructed around neighbouring star systems – some even larger.
Having begun its journey to the stars in the 22nd century, humanity is reaching a landmark in its exploration of space. A region nearly 1,000 light years in radius has now been settled (or about 2 percent of the total length of our galaxy).
Well, I understand that the sphere would be made by kinds of matter that is unimaginable today (this is obvious) and the Dyson sphere could have several walls and some of the portion of such walls could be terraformed. But I didn`t get when it says that such artificial worlds would be strange - strange in which sense? Could the terraformed portions look alien and artificial compared to life on Earth? And what about the other portions of the sphere - Could material science be so advanced that these artificial worlds would be really dazzling, bizarre and surreal even for science fiction addicts? I believe that these worlds would be so bizarre and large that even virtual reality would not replace the will to visit them.
If a person was in one of these worlds inside the Dyson sphere and looked at the sky, what the sky could look like, since they would be inside a set of hollow closed shells? Would this person still be able to see stars or the sky could look like something else?
It is also written as if the world population will increase in trillions of people as humanity have the technology to create artificial beings - even sentient humanoid animals.