collisions

I have problem with entityradius.
(the collision between model and map is sliding collision)
When the entityradius is good (after the translateentity 0,-1,0 the model is on the ground) he can't go up the stair
or on upgrade.
When the entityradius is big, the model can go up on the staire but is float above the groud.
What is the solution?

Purt an ramp over the top of your stairs. And give it an alpha value of 0, so collisions are still detected but it can't be seen. Easiest way i think :)

I will try, thank you