You don´t need to invent all the previous technologies and you can start with the one you bought. But the wiki says that:
"Research speed depends on the following items: is the technology world-wide known? is it available for sale? what about the previous technological level? how did you get this technolgy - purchased or invented? what about your "Science research" qualification level?"
So your speed is affected by the tech you already self-invented. I don't think anyone made an analysis of the influence of those factors on the research speed; I would say it's up to you.
To have a better idea I invented 7 levels of tech (outwear, from 2 to 8) in 79 weeks.
But for my pig farms I began researching from lvl 4. In comparison:
I invented tech lvl 4, 5, 6, 7 of outwear factory in: 44 weeks
I invented tech lvl 4, 5, 6, 7 of pig farms in: 56 weeks (the difference is bigger for lvl 4 than for lvl 7)
Nevertheless self-invented lvl of tech are not the only factor on the speed.
Concerning the sale of tech, they are immaterial so the difference with a good (material) is that you are going to "share" your knowledge, no giving it away. That means that you are keeping your tech when you sold it and as long as it is on the market and that someone wants to buy it, you can sell it (at my lvl, I sold some tech 13 times). |
