BITTEST

if (bot->bot_mode == RT_BOT_PLATE || bot->bot_mode == RT_BOT_PLATE_NOCOS) {
	    if (BU_BITTEST(bot->bot_facemode, surfno)) {
		/* Append full thickness on both sides */
		los = bot->bot_thickness[surfno];
	    } else {
		/* Center thickness.  Append 1/2 thickness on both sides */
		los = bot->bot_thickness[surfno] * 0.51;
	    }
	} else {