since you are talking mipmapping, here is a little script for it, its an action that can be assigned to any model (simple box) and placed in the level to control the mipmapping. There might be another way, but this works perfectly for me...
its small, simple, and for me, easier to control, since I dont have to search my main.wdl.
I like assignable actions...
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-Add "mipoff.wdl" to main world folder
- include it in your main .wdl file
-apply "mip_off" action to entity cube

This is the meaning of d3d_mipmapping (from the instruction text):

d3d_mipmapping = 0 -> Mipmapping deactivated
d3d_mipmapping = 1 -> polygon mipmapping (old method)
d3d_mipmapping = 2 -> scanline mipmapping
d3d_mipmapping = 3 -> trilinear mipmap filtering (new default)
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//wdl code: (mipoff) change the number to match above options...

//startCode
action mip_off
{
d3d_mipmapping = 0;
SET MY.INVISIBLE,ON;
SET MY.PASSABLE,ON;
}