One place steel will probably be better than adamantine in terms of axes and spears are the alternate attack styles that a blunt attacks; pommel strikes with swords, blade flat with axes, and shaft strikes with spears. In those cases the higher weight of the steel weapon will be superior.
I forgot to mention that I eliminated all the alternate attacks for axes, so that they can only hack. Good thought though.
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I looked through the logs, and found that the steel battle axes were sometimes deflected by iron greaves. I haven't run a systematic analysis yet, so there may be other contributors.
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It could be because when you're hit in the lower body, mail shirts, breastplate and greaves all overlap. So an attack could be considered deflected by greaves (outermost layer) because it didn't punch through all layers of armor.
Were greaves deflections all from the lower body or also other bodyparts?
There were definitely deflections from all parts covered by greaves. Also a good suggestion.
Try lowering MAX_EDGE of all metals to an (equal) low number, and then see if there is a difference between adamantine and steel when it comes to cutting up weaker-than-steel materials.
I tried this, and the addy axes still win 643 to 541 (I only ran one round of 1152 this time). This ratio is consistent with the original test with addy's MAX_EDGE=100,000. I would have really liked this to work, as that would say that MAX_EDGE (and hence weapon quality) actually does something to impact damage, but it seems not. Here's to hoping we eventually find a case where it matters in the range normally used by weapons...
Since deflections seemed to be coming primarily from the greaves, I tried another test where I removed the greaves. I kept all other armor components (iron breastplate, mail shirt, helm, gauntlets and low boots) and set MAX_EDGE back to 100,000 for addy. As mentioned above, dwaves wielded axes modded to only have hacking attacks. These tests used standard dwarves, not arena dwarves (as I forgot to check that until just now and for some reason had switched back to standard dwarves the last time I ran tests). Anyway, with bare-assed dwarves, the dwarves wielding steel axes win 1238 to 1167. This is a fairly close, but the difference is just over two standard deviations, so it appears to be significant.
Urist - I believe you said at one point you have a formula for calculating the contact area of body parts, but I wasn't able to find it. My current theory is that the chance of deflection goes up of the contact area of the weapon is similar to the size of the body part, or something like that (as axes deflect more off the large dwarven asses, and bolt deflect more off hands, feet, and heads). Anyway, it would be interesting to plot deflection data vs. body part size.
For these tests, I plan to next pit dwarves vs. elephants, for both practical and historical reasons. I will probably give the dwarves shields, and max out shield, dodge, and armor use skills, as I'd prefer to measure how many hits it takes a dwarf to kill an elephant, not the other way around...
Edit:
And the results are in. Addy does seem to have a clear advantage for killing elephants. I gave dwarves full adamantine armor with adamantine shields. Dwarves were great fighter/axedwarf, grand master armor user, shield, and dodger. All gear in this and previous tests was standard quality. When given steel axes, dwarves killed 949 elephants in 29807 hacks, with 164 dwarves dead. With adamantine axes, 1032 elephants were killed in only 4828 hacks, with 90 dwarves dead. I will have to try running again with MAX_EDGE lowered for addy, but I really should go to work now...
Edit #2:
Work is overrated anyway. I ran again with addy's MAX_EDGE set to 10,000, and this time I found that dwarves killed 978 elephants in 7036 hacks, with 160 dwarves dead. This appears to be a significant difference compared to MAX_EDGE=100,000, so I'd say it does matter here. However, it's also not the same as steel, so other things seem to matter as well.
Summary of my conclusions so far:
(1) Steel is as good as (and maybe a little better than) adamantine for fighting armored humanoids with at maximum iron armor.
(2) Adamantine has a clear advantage for fighting large creatures (elephants).
Given that steel-clad dwarven axelords can easily decimate goblin invaders, gaining a slight advantage in killing them using steel axes is not very important. This is clearly outweighed by the advantage adamantine gives in killing large creatures, which actually pose a threat to a skilled military. Time to go make my dwarves some adamantine axes...