Mid Texture on 3D Floor

This has probably been asked a million times, but I haven't found anything specific in my search.

I have a rail on a 3D floor. If I set the linedef as impassable, the player is unable to walk under the 3D floor where the linedef is located. The 3D floor is raised up quite a bit, and I don't want the player to fall off. Is there a trick that I can do that will allow me to set the impassable flag and still allow the player to walk underneath the 3D floor?

Here's an image that may assist:

Use a 3D middle texture; it's the simplest method.

Gez said:

Use a 3D middle texture; it's the simplest method.

I'm using GZDoom Builder, but don't see that flag anywhere.

If you don't use UDMF you have to set it with the Line_SetIdentification special.

Graf Zahl said:

If you don't use UDMF you have to set it with the Line_SetIdentification special.

It is in UDMF.

It is there, but with a different name in the configuration file:

linedefflags_udmf
{
	monsteractivate = "Monster activates";
	blockeverything = "Block everything";
	blockplayers = "Block players";
	blockfloaters = "Block floating";
	translucent = "Translucent";
	jumpover = "Jump-over railing";
	zoneboundary = "Sound zone boundary";
	clipmidtex = "Clip middle texture";
	wrapmidtex = "Wrap middle texture";
	midtex3d = "Walkable middle texture";
	blockprojectiles = "Block projectiles";
	blockuse = "Block use actions";
	blocksight = "Block monster line of sight";
}

Gez said:

It is there, but with a different name in the configuration file:

linedefflags_udmf
{
	monsteractivate = "Monster activates";
	blockeverything = "Block everything";
	blockplayers = "Block players";
	blockfloaters = "Block floating";
	translucent = "Translucent";
	jumpover = "Jump-over railing";
	zoneboundary = "Sound zone boundary";
	clipmidtex = "Clip middle texture";
	wrapmidtex = "Wrap middle texture";
	midtex3d = "Walkable middle texture";
	blockprojectiles = "Block projectiles";
	blockuse = "Block use actions";
	blocksight = "Block monster line of sight";
}

So, check "Walkable middle texture".

That was it. Thanks so much for the help.