Time Development Points
In order to use TDPs to raise a stat, one must go to a designated room for training that particular stat and type TRAIN or STUDY twice to confirm. Training rooms for each stat are available within or near every major city.
A new character is given 600 TDPs right out of the Character Manager. After that, the only way to gain more TDPs is by circling or obtaining new ranks in skills.
TDPs from Circling
Each time you circle, you will gain a base number of TDPs plus a bonus based on your circle. Below circle 10 you get a base of 50 TDPs. Circle 10 onward, you will gain 100 TDPs as a base. The bonus TDPs are always equal to the circle you just attained. For example: if you attain circle 27, you will get 127 TDPs.
TDPs from Leveling Skills
Each time you gain a new rank in any skill, the integer value of that rank is added into a hidden pool (the TDP pool). If at any time the total in the pool reaches or exceeds 200, you gain one TDP and 200 is subtracted from the pool. This also applies for multiples of 200: if the TDP pool reaches 400, you gain two TDPs and 400 points are subtracted; for 600 you get three TDPs and 600 is deducted from the pool, etc.
For example, let's assume that your TDP pool is currently zero. You increase your Perception skill to attain rank 150. 150 points are added to the TDP pool. You then increase your Leather Armor skill to rank 66. 66 points are added to the TDP pool, making a total of 216. You gain one TDP, and 200 points are subtracted from the TDP pool leaving 16 points. Next, you increase your Arcana skill to 197. Your pool increases to 213, you gain yet another TDP, and the pool is reduced to 13.
Since the experience change where all tertiary skills less than 100 ranks are learned at the rate of secondary skills, it is considerably easier than it was to level tertiary skills for the sake of TDPs alone. Leveling a single skill to 100 ranks will result in a gain of 25 TDPs when all is said and done. Leveling a skill to only 50 will result in a gain of 6 TDPs.
Death and Losing TDPs
When you lose ranks from memory decay as a result of death without rejuvenation, your TDP pool will be reduced by the ranks you lost. If this sends the TDP pool below zero you will lose a TDP, and 200 will be added to the pool. This process makes it possible to have a negative number of TDPs.
In mathematical terms, the total number of TDPs gained from a single skill is the floor of the sum of integers from 0 to the maximum earned rank divided by 200 Since that summation is a closed set, we can express it as follows:
Since the "hidden TDP pool" is shared between skills, the floor function operates on the sum of skills, instead of each skill individually. The formula to calculate the total TDPs gained from all skills is as follows:
TDPs granted from all levels gained can be expressed with the following formula: