Science & Industry

I am thinking of branching into manufacturing and I have been trying to make a spreadsheet to determine the profitability of various items. I've been using formulas verbatim off the internet and comparing the results to EVEMon's numbers and I always end up off. I am honestly unsure just how EVEMon arrives at the numbers it does. For instance, Production Efficiency shaves 4% off the materials needed per level trained in the skill. I have been looking at making scourge heavy missiles. 120% of the base price of 812 tritanium for scourge heavies in EVEMon is 996, but in actuality this number is 122.66% of 812!

I tried using Grismar's formula:

mineral cost = base cost * (1 + 0.1 / (ME + 1)) * (1.25 - 0.05 * ProdEff)

Using a base price of 812 tritanium this gives me an absurd 1,218 tritanium instead of the true 996 tritanium with ME and PE of zero.

Even when forgetting about Production Efficiency and focusing only on ME I still get it wrong. I tried using this formula:

mineral cost = (base cost * 0.9) + (base cost * (0.1 / (ME + 1)))

Using a base price of 812 tritanium and a ME level of 1 this equation results in a tritanium cost of roughly 771 (which is 95% of 812, the number it should be with only 5% waste given from a ME level of 1) when according to EVEMon's math wizardry the tritanium cost with those parameters should be 775 (95.44%)!


Would anybody be so kind as to point out what I'm doing wrong, and optionally post whatever formula you use yourself (which preferably utilizes a Production Efficiency variable)?

This has me one step closer!

The last thing is my PE is actually zero right now (don't worry, I'm going to train it up to at least 4 before I actually manufacture anything). The formula works with a PE level of 5 (since at the very end you are just multiplying everything by 1), but when you plug in a zero instead, the result is about 1,015 tritanium instead of the true 996 tritanium.

How do I need to modify the PE section of the equation (1.25 - 0.05 * PE)?

EDIT: Disregard this post. Modified it to (base price * (1+0.1 / (ME+1))) + (base price * (0.25 - (0.05 * PE))). It works now.

Ah good find. Guess that means production efficiency only modifies the base cost, didn't know. I guess I never bothered to check, although I am quite new to manufacturing myself so it doesn't surprise me!

Now that my material conundrum is solved I have been working on the manufacturing time part of the process to get a rough indication of ISK in assets created per hour spent manufacturing various items. Using the base manufacturing time of 300 seconds for scourge heavies, an Industry skill at level 3, PE of zero, and the above formulas, I arrive at a manufacturing time of 264 seconds when EVEMon tells me that with an Industry skill at level 3 and a PE of zero the result should be 240 seconds.

I'm assuming the formula is right and the base of 300 seconds I'm using is wrong. Curiously with an Industry skill of level 3 my manufacturing time should be reduced by 12%. Looking at scourge heavies in EVEMon tells me that my true manufacturing time is 4 minutes when the base time is 5 minutes. 4 is 80% of 5, not 88%, so again, I'm assuming my base is wrong.

If 300 seconds is not the base I should be using, how should I be modifying my base?

Base time for nearly all ammo is 4 minutes = 240 seconds.

At P.E. 0 the BPO shows 300 = 5 minutes. There is 25% waste.

Base Manufacturing Time = ROUND( Time Shown On P.E. 0 BPO / (1 + 25%) )
= ROUND( 300 seconds / 1.25 )
= 240 seconds = 4 minutes

Total Time = Base Time * (1 + 0.25 / (1 + P.E. Level)) * (1 - Industry Skill Level * 0.04)

Base time = 240
P.E. 0 = 25%
Industry 3 = -12%

240 * (1 + 0.25) * (1 - 0.12) = 264 seconds

Anything else and EVEmon is wrong, unless you found a BPO without 25% waste on production time (I've never seen one).

When dealing with M.E. and P.E. it is very common to find web sites and tools with wrong numbers. Most of the errors are explainable.