I came up with an idea for climbing stairs smoother by making the actual stairs passable, and making a "ramp" over top the stairs invisible but the player would actually be walking on the invisible ramp, not the passable stairs. However my problem is, if I check the "none" on the ramp, all textures in the map become black and the ramp is invisible as it should be. Why do all the other texutures become black??

You have to show your code, because you probably did more than just 'check'...

Are you sure youre setting it through the "surface" panel and not the texture panel? When you select the "none" flag in the texture pan the setting is applied to whatever has that texture.

On a side note, setting the "none" flag just makes it so the block doesnt have a texture. the physical properties are still rendered aka the block will just be invisible. Solution? Make the block into a map entity or a model then set it to passable.

Just do a model and check the INVISIBLE flag