in this world just like weapons are different to give to edge to the user spells can be made to give an edge to the spell caster. spell casters can combine spells or tweak other spells.
in order to make a new the player needs to make a spell craft check the tougher the spells the harder the check.
spellcraft DC 15 + spell levels
general spell creation rules
you can apply meta magic feats just like any original spell
the players casts the spell they use the highest spell used in the creation to apply saves etc.
if a player combines two spells of different levels the spell level is the highest spell level use in the creation +1, burning hands +scorching ray spell level to cast 3. the same applies for tweaked spells burning hands tweaked is 2nd level spell.
to tweak a spell for example radius each time the radius is increases full counts as a spell. making burning hands radius 60 ft is two spells 90 ft is three spells for determining the DC check but only costs 1 spell to cast the new tweaked spell.
for making a touch a ranged touch acts the same as creating a bigger area.
you cannot combine two of the same spells together or the same spells that are greater and lesser except for when you are tweaking the spell.
if you are combining two spells that are not touch but with different saves the player chooses the saves the same goes for if it is a touch and a save spell.
when a permanent spell is tweaked you cannot cast it like it was untweaked but the spell can be learned again in its untweaked form
for spell casters who prepare spells, the player needs to do the spellcraft check when they prepare their spells. the spell they craft uses up the spell slots of all of those spells used to create the spell. this has to be done everyday if you want the same spell. if you did not use the spell the day before the dc for the check is reduced by three. if the player fails the check they lose all of the spells they were using to create the new spell for that day.
for spell casters that know spells the spell creation works differently. they can either choose to make a spell they create permanent or for just one time. for make a spell permanent the spell caster must make the check. this does not remove the other two spells from the list when creating the spell. it is just a new spell. if the spell caster chooses to make it permanent they can no longer change the spells made to create it. this new spell is 1 level higher than the total level of spells used. you can craft already tweaked spells. if they want to create it for one use they need to create the spell when the are going to use it ( they are allowed to create the spell and cast it in the same turn) to do this the player needs to make the spell craft check and an additional concentration check. if the spell caster fails when trying to make a permanent spell he loses all the spells that he can cast for that day in each level spell slot depending on the level spells he uses. for example 1 and 2 level fail they lose all level 1 and 2 spells for that day. when creating a non permanent spell and fails he looses the spells he was trying to create and cannot canst any spells next turn.