How would I make it so after a research is upgraded, a builder's building selection changes? I.E: You research a tower upgrade, and your builder gets a new tower in place of the old one in his building selection.
I have searched the triggers, and have not found a way to do this, but im pretty sure it can be done.
And- is it possible for me to make it so that once an object is built, you cannot build another untill that one is destroyed? Thanks for all your help!
On the first part, all you do is have a trigger that replaces all of the workers with the exact copy of another worker just with different buildigns in there "buildings able to be built" I'll talk to you about this later, ON your second part, All you would do is make a variable called something like p1_tower_built, It would be an interger. Now you would have a trigger that would add 1 to the variable and have another trigger that would check to see if the variable was a certain range (i.e lessthan or equal to 5 is ok greater than 5 is not ok) I can help you with more, just email me
Perhaps you could make the builder able to build all of the different levels of each building, and then restrict the player from building all but one of each building.
As the new conditions are satisfied, you then restrict building on the old "tower" and unrestrict building on the new one.
Thanks all- I think i got it . Divine, I knew how to do the max unit quota (part two) by using variables- but i was hoping I could avoid using them . Thanks again everyone!
. Divine, I knew how to do the max unit quota (part two) by using variables- but i was hoping I could avoid using them 
. Thanks again everyone!