# Physics

Im having a heck of a time getting my physics right. Is there a good balance between gravity, mass, and walking up and down stairs properly? The stairs seem to be a challenge for my character. If I make it to walk up the stairs, coming back down it floats. I had to use two invisible planes on the stairs one for the character to walk on and another above it to hold the character from floating. It seems like more trouble than I need.

Well the gravity in the game engine supposed to be the same on earth. But for some reason it’s not like earths gravity. You can change the gravity settings on world settings, a slider called gravity. Afther that notice that you need to add more motion speed to have the same results on lower gravity.

I scaled down the world and adjusted gravity. Now there is no sliding and the character goes down the stairs well. Now it wont go up them. It gets stuck on the bottom stair. I wonder what I should try?

I’m a newbie, so you can ignore this at will, but invisible objects can still have object collision I’m pretty sure, so you might could put an invisible ramp at the bottom stair.

Or put an invisible ramp on top of all the stairs A technique they actually use much of the time in “real” games.

Okay, its good to know that my original layout with ramps is actually used. But I dont understand why it wont go up the ramp. If I set the mass or gravity or dampening down it goes up the ramp fine. But then once I hit the ground (a flat surface) it speeds around like crazy. Adjusting all the levels I just cant seem to find a balance. Is it bad to use the motion actuator? Should I use Python? If so what is an easy script for this?

That would be normal physics to speed up going down.
You might need to control linear velocity on the stair, part of the motion actuator. Again, newbie here. I’m just reading most of this stuff and it’s not documented very well. Do physics still apply if you control linear velocity? You can also try to adjust friction on the ramp, I think.