Mana Games

[Togtdyalttai]

I wasn't sure where to post this, but would it be possible for you to tell me, Manu, what the court pace ratings for each of the TE courts is? For example, the pace used in the US vs. Switzerland tie in real life is 46. Thanks.

[manutoo]

According to this page http://www.itftennis.com/technical/equi ... /class.asp , the BG-cement in TE is be 42.5, Clay is 40.5 and Grass is 59.

You can calculate other courts by yourself, extract the "Court.ini" for each court (read "Data\HowToMod.html" for details), and look for Friction & Elasticity ( => coeff of Restituation in the ITF's page).

I may do some tunings after have read some info from ITF...

[Togtdyalttai]

Hey Manu, I just started looking at these ratings, and I see two numbers under friction and two under elasticity (at least for clay, which happened to be the one I looked at first). What does each mean? The format is 1st number // 2nd number.

[manutoo]

// ==> mean comment, whatever is after is ignored by the game engine...
Here, the numbers put in comment are the one from TE2005, or maybe TE2004...

[Togtdyalttai]

Ok, so then the court pace ratings are as follows:

Clay: 33 (I take it you lowered this recently) (Medium Slow)
Grass: 59 (Fast)
Classic Synthetic: 37 (Medium)
Cement: 41 (Medium Fast)
Indoor Carpet: 50 (Fast)
Indoor Hard: 47 (Fast)
Blue-Green Cement: 42.5 (Medium Fast)
Newline Synthetic: 38 (Medium)

I like where most of these ratings fall on the spectrum. However, I think clay should be even slower, probably in both elasticity and friction. I'd like to see it be under the slow category.

[Leena]

Going by the categories on that page:

Clay - Slow.
Rebound Ace (Classic Synthetic) - Slow.
Decoturf (Blue-Green Cement, most of the US Summer Hardcourt tournies) - Medium.
Plexipave (Cement, most of the other Hardcourt tournies) - Medium.
Plexicushion (Aussie season) - Medium.
Greenset, Taraflex and RuKortHard (All indoor tournies, except whatever Memphis and Zagreb have which is extremely fast) - Medium.
Grass depends on the maintenance of the court... Wimbledon is probably near medium now, whereas Queen's Club is fast.

Also, I've always thought the term synthetic is used for fake grass events (mostly in Japan), and fake clay surfaces, none of which are on the main tour anymore. I suppose the old Rebound Ace was technically synthetic since it was made with old rubber tires and sand, etc..., but Plexicushion is not, whatsoever.

[Togtdyalttai]

Leena, I think that Rebound Ace would be Medium-Slow. It's slow, but not as slow as clay. As to the indoor tournaments, I agree with you, but as an average of the two, it should be more like medium-fast, maybe a little bit faster than BG.

[Leena]

I just put what the ITF site said. If we go by them, every surface but clay or grass would be medium, so that's not a good idea.

I think the elasticity and effect on spins is more important. For the most part, they're fine in this game. The exception being Rebound Ace, where slice and topspins are very effective, IRL. It just plays like a slower hardcourt in TE. And I think topspin effect needs to be lowered drastically on clay, but that's more of a game issue.

[manutoo]

I was trying to tune the clay court to make it slower according to ITF rates, when I thought something was wrong with their pace calculation.

So I looked again, and I found more detailed specs here : http://www.itftennis.com/shared/mediali ... iginal.PDF (7.7MB)
It turns out that what they call "friction" isn't the "friction" that is usually used in physics.

From their specs, it turned out that :
ITF coeff of friction = 3.5 * (1 - Friction) / (1 + Elasticity)
(Friction & Elasticity are the ones from the "Court.ini")

So when you use this formula to calculate the pace, it turns out that most TE surfaces are very slow, slow, or at best medium.

I don't think what they call slow & fast is actually what players call slow & fast. What they call slow & fast seems to be a lot more related to the percentage of outbound ball speed compared to the inbound speed.

Leena, I think that clay surface is known to be the one that emphasise the best the topspin effect, no ?

[Togtdyalttai]

I was trying to tune the clay court to make it slower according to ITF rates, when I thought something was wrong with their pace calculation.

So I looked again, and I found more detailed specs here : http://www.itftennis.com/shared/mediali ... iginal.PDF (7.7MB)
It turns out that what they call "friction" isn't the "friction" that is usually used in physics.

From their specs, it turned out that :
ITF coeff of friction = 3.5 * (1 - Friction) / (1 + Elasticity)
(Friction & Elasticity are the ones from the "Court.ini")

So when you use this formula to calculate the pace, it turns out that most TE surfaces are very slow, slow, or at best medium.

I don't think what they call slow & fast is actually what players call slow & fast. What they call slow & fast seems to be a lot more related to the percentage of outbound ball speed compared to the inbound speed.

Leena, I think that clay surface is known to be the one that emphasise the best the topspin effect, no ?

Wow, those ITF people are crazy.

[Togtdyalttai]

With that new definition, the court pace ratings are as follows:

Clay: 18 (Slow)
Grass: 31 (Medium Slow)
Synthetic: 19.5 (Slow)
Cement: 18 (Slow)
Indoor Carpet: 24 (Slow)
Indoor Hard: 22 (Slow)
Blue-Green Cement: 19.5 (Slow)
Newline Synthetic: 16 (Slow)

WTF!!! I need to look on that site that you suggested, Manu, to see why they use this way to classify the courts. It makes absolutely no sense!

[Togtdyalttai]

Ok, so it doesn't make any more sense to me than it did before, but this is what the site said to do to calculate the CPR once you get the COR and COF: CPR = 100(1? u)+ 150(.81 ? e) where u is the COF and e is the COR. This formula outputs pretty much the same values as the chart, as it should. After looking at this stuff, I feel like I'm back in Physics class

[manutoo]

yup, and :
COR = e = Elasticity in TE ; they are all same
and :
u = coeff of friction = 3.5 * (1 - Friction) / (1 + Elasticity)
in the pdf, they give :
u = (vix - vfx) / (viy * (1 + e))
in TE, vfx = vix * Friction, so it gives :
u = (vix / viy) * (1 - Friction) / (1 + e)
vix / viy = cos(16°) / sin(16°) (coz the ball comes with an angle of 16°) = 3.5 ; thus :
u = 3.5 * (1 - Friction) / (1 + Elasticity)
If I'm not mistaken...

[Leena]

Leena, I think that clay surface is known to be the one that emphasise the best the topspin effect, no ?

Yes, but I think it's ridiculous in gameplay. Try playing against Justine or the Moroccan girl in World Tour that have 100% topspin and accuracy. They force you to the backstop on every topspin ball. Even the dreaded moonball matches with Martinez vs. Coetzer in the 90s couldn't do that.

[Brad1981]

I like playing at topspin around 30-40% range, both me and cpu. In my opinion, I find that having a topspin level higher than 50% is just unrealistic. Having a high topspin value is ok for other shots, but for the topspin strike, it makes it loop way too much I think. Maybe in a future release or future version after 2009, we could have the ability to adjust the loop of the topspin-only strike. Because I think it loops too much when set anywhere over 50%.