Fall through mapmodels

[flowtron]

The video only shows the issue of the physics engine working in discrete steps - thus the velocity you gain by the hitpush of the nade explosion has pushed you through the solid part of the model before the engine checks for resistance - this is a well-known "bug/feature" in cubeengine games and was used with jumppads with insane values for sauerbraten maps before the kill-material came around.

To make a model non-clipping you just need to set the height of the bounding-box to 0.
In the general format of the command

[SELECT ALL] Code:

mapmodel R H Z 0 N

that means making H be 0.