These parameters determine three things: the Magicka cost of casting the spell, the minimum level of skill required in order to cast the spell, and the gold cost of making it. Select a spell effect, and a new screen pops up where you can set the range (self, touch, or target), area of effect if appropriate, magnitude and duration. This list only contains the effects of spells that you know and are able to cast (see Acquiring Spell Effects for details). On the left you are presented with a list of all the magical effects you can use to make a new spell. When you activate the Altar of Spellmaking, the spellmaking window appears. A fourth altar is found in Frostcrag Spire, if you have the official plugin, but you must purchase the magetallow candles and upgrade the altar before it can be used. A third altar is available within the Arch-mage's personal quarters in the Arcane University once you complete the Mages Guild quests and become Arch-mage.
These are only available to members of the Mages Guild who have completed all the recommendation quests in order to gain access to the University. There are two within the Praxographical Center building at the Arcane University. Custom spells can only be made at an Altar of Spellmaking.
