Normally, viewing the 3D item model for items (bar special cases like equipment) is limited to the game's debug menu. However, if you have a Lure Rod and are willing to discard it, you can bypass this restriction. When in the item menu, pull up the stats for the Lure Rod, and then discard the Lure Rod: its stats will still be displayed onscreen however. Pick up an item and carry it to the spot where the Lure Rod was. While hovering over that slot, press Square twice, then Circle; you will have done this correctly if the Lure Rod's name is replaced by the item's name. Then equip any weapon or article of clothing and you will see the item's model. Do note that this only works one time and to do it again you'll need to procure another Lure Rod. Note that trying to display outfits crashes the PS2 version, and often does so for the PS4 port as well albeit with varying effects.