Ladies and gentlenerds,
I would like to present to you a little tutorial about "how to make smooth ramps and loops".
First I wanna explain how it works generally. Every 3D surface is made of plain parts that are sticking together to build an object. For example, a cube. 6 sides building a 3D object. That cube is far away from a round ball. But if you start cutting of all eight corners of that dice, you get 8 more sides. Makes 14 and it looks a bit more "rounder". If you cut all new corners again, you get another 24 sides, this makes 38 sides. On and on... this cube is going to look more and more like a ball. Until those cuts are so many and so tiny, your eyes see a perfect ball.
That's how polygones in games are working. The older ones of you, who grew up with old Nintendos or the first Playstation will remember the culmsy and edgy looking first 3D graphics of this time. Best example for this time was Tekken 2. The characters where looking like thes've been carved out of wood.
The calculating power of earlier graphic engines was so lame, they couldn't work with much polygones at all. No compare to graphics nowadays. Every Character has millions and billions of polygones, so you cannot see any edge at all. See here the latest graphic of Tekken 7 for example.
Looks realistic, huh? No compare to old graphics. But BBR's graphic engine is really simple. But way better than Playstation 1 or 2 ever was. So... what does this all have to do with building tracks and loops?!
Easy... everything you're building with brushes is based on the same geometric and physical laws.
Just guess you wanna build a skate ramp in you backyard. For a start, you lay one wooden plank on the ground, the second one is standing at your wall. And? You've get a 90° angle you can't ride. If you put another plank between them, half the angle, you will get 3 planks with 0°, 45° and 90° angle. Can you ride it, yet? No way! So you start putting smaller planks above the corners between each plank. And the more you do that, the smaller your straight planks get and the ramp is getting smoother and rounder.
So... if you made a ramp in a 90° Corner (made of steel ingame for example) and you see, that your ramp is not that smooth... just ad or delete carefully tiny bits to break straight lines and get more tiny lines. The more lines with different angles you create, the smoother and easier to drive your ramp will become.
Not so may straight lines let a ramp look bumpy:
But the more you break those straight lines, the more different smaller lines you will get, and the ramp becomes more smoother and better to drive:
This technique you can use even on straight roads to evade to much bumpers or potholes which may affect your driving abilities.
That's it. Hope it gets a few of you to understand how some of us are making really smooth loops and ramps.