yes I know visualization is a must to find even minor or rare bugs.
as I know draw_line3d uses one particle for each line, and particle rendering can have a clipping distance by clip_particles given in percentage of clip_far... but as I tried it does not work.
at draw_begin you can find an example of drawing a triangle by DirectX, maybe it could be extended and used for a whole mesh, maybe faster because no entity and particle extra stuff used.