I think not only absorbing, but also changing them, the sound resulting from a harmonic box is rich because of that, is many waves, similar waves, at the very same time. I also think most people is mistaking the term metallic for some high pitch harmonics, even some called it artifacts when they are present on samples and acoustics as well.

The wood is a different impedance than metal, a different dielectric, so the resulting wave will have different energy and shape, is like throwing a ball in a box that every time it rebounds will split in two, at a slower velocity and with a different shape. Every instant the amount, direction, speed, etc of every ball will be different while the sound is the sum of all of them. On a metallic surface the ball rebound faster, also the wave and changes less its shape.

For wood I understand the moving of the sound, as you have many similar frequency at the same time, you get a sound that changes in time until fading, a rich sound moving in the air. I think Pianoteq 4 is amazing doing that.

I may read too much "ad copy" but there are (claimed) structural differences between the way for example Steinway and M&H build their cases vs Bosendorfer.
Laminated maple bent in a press vs "butcher block" spruce. 

I suppose one could argue that the bent laminates have internal tension that adds some ringing, despite their aging in a warm and humid chamber to "relax" them.
Whether or not the already relaxed spruce blocks are better/different ??
I would guess different, but there are so many other variables in physical piano design & build that these differences may be minor (however good the ad copy may be).

My favorite guess is still the cavity, not the "wood" itself.
Lid position makes SO much difference to ANY physical grand;  open box, half open box, closed box.
These are very different objects when viewed as cavities.
I don't mean just VOLUME or sound reflected from the lid to the hall, I mean what goes on IN the "box".

Fun to speculate on all this, but I have to add that V4 is plenty good enough for my ears and playing level.

The wood is a different impedance than metal, a different dielectric, so the resulting wave will have different energy and shape, is like throwing a ball in a box that every time it rebounds will split in two, at a slower velocity and with a different shape. Every instant the amount, direction, speed, etc of every ball will be different while the sound is the sum of all of them. On a metallic surface the ball rebound faster, also the wave and changes less its shape.

For wood I understand the moving of the sound, as you have many similar frequency at the same time, you get a sound that changes in time until fading, a rich sound moving in the air. I think Pianoteq 4 is amazing doing that.

Soundboard impedance could be referring as wood, depends of how its used. The material of a soundboard, even two types of wood, will have different impedances.

Alternatively, perhaps what we refer to as "wood" is what wood adds to the sound by subtracting (absorbing) some frequencies.
Thick heavy planks of wood ABSORB sound very well, thin tone woods in violin plates"sing".

I see a lot written asking for "more wood" and "less metallic", often in the same sentence.

I wonder if these are the antithesis of each other, i.e. if one were to add filters to take away the frequencies that wood absorbs - does that lead to less "metallic" and more "wood" ?

Not that subtractive synthesis is new :-D

There are also some interesting discussions in other forums on carbon fiber soundboards, thinner and lighter lids, ABS plastic cases, etc.

And guess what...  Soundboard it's made of wood.   ,,,  Or do you wish to take it away too???   

My guess is that pianoteq do emulate the piano body, but perhaps just the interior effect, the piano body as a resonance box, the inner sound erradiation, but not much the outer sound erradiation,  I mean, the sound created by the external wood vibration.
Neither V-piano or physis piano have such woodness you wish.   

By nowI really curious to see a add-on of a vintage grand piano using the actual refined soundboard model of D4.

If I understand you correctly .... You are suggesting that even IF the sound that we attribute to WOODINESS is actually due to the presence of WOOD in the piano, it may be possible to examine the effect that WOOD has on the sound and mathematically duplicate that effect electronically.

It makes sense, I guess, because what reaches our ears is not WOOD.... it is a sound wave ... and sound waves can be generated through mathematical processes.

I hope you are right.   

Actually, I am sure you are.    I am also sure that the MODARTT team is very aware of all of this and much, much more.   I am confident they will be able to continue improving this great product.

So, Pianoteq managed to emulate the characteristics of metallic materials in a piano, judging by how metallic the sound used to be (and to some degree still is). In order to add more wood, they need to better emulate the characteristics of wood materials, their response to vibration, etc. This may not be that easy but I believe it is not impossible.

P.S. English is not my native language and I apologize if what I write is incomprehensible or confusing.

Ahhh, until a negative proof is established I shall continue to believe that the undefined variable "Woody Sound"  can be achieved, EVENTUALY.

Well, my "beliefs" are firmly rooted in logic and when I see a way to "get to the bottom" of something, I go for it.

If I was a member of the MODDART team, I would be out right now purchasing a very nice WOODY sounding piano from which to strip away all the WOOD and then see what it sounds like.   Because, if it does not sound woody without the WOOD, then they will know the solution cannot be found in algorithms but in ... who knows what ...

Well, what I am suggesting is that .... maybe it can't be done without WOOD.

Maybe a real piano will not sound like a real piano if you take away that wood.

Maybe this should be explored by MODARTT.

I am not so sure that you can get the WOODY sound without WOOD.

Ahhh, until a negative proof is established I shall continue to believe that the undefined variable "Woody Sound"  can be achieved, EVENTUALY.

I haven't got into it, I suspect that it is some interaction of cabinet and cavity resonances - along with harp, soundboard, etc.

Somewhere I vaguely remember that a particular guitar, when analyzed, was found to have a resonant frequency of the cavity that was a perfect fifth from the resonant frequency of the spruce top - the top of a guitar being the soundboard of a guitar.

Maybe a real piano will not sound like a real piano if you take away that wood.

Maybe this should be explored by MODARTT.

I am not so sure that you can get the WOODY sound without WOOD.

Modartt, to my point of view, wants weverything in the modelled universe. If they want to add extra woodness, will try to find a way that this will interact with all other elements.  They want a living machine.

I'm sure they can run a test, to get just the pure sound of wood for each hey strike, and could add it as sampled sound over the modelled sound, in the same way the hammer noise, but it would lost some of the living aspect of pianoteq.

I would like to hear of someone taking the "wood" away from a previously "woody" piano and see if it then sounds like Pianoteq.

Then we would (no pun intended) know if "wood" is the missing link.

Anyone have a "Woody" concert piano to donate ?

Also, I agree that the mathematics of computing convolutions efficiently is complicated, but conceptually, the idea is quite simple. It's just like playing many copies of the same "response" sample on top of each other, one for each sample point in the input waveform, where each copy starts at the time-offset of the sample point and has an amplitude given by the sample value (which may be negative). So, if the response lasts for a few seconds, that's equivalent to playing more than 100 thousand samples simultaneously! That's why you need some clever math tricks.