I'm trying to model a plywood texture and was hoping someone here would have
some insight for me.

The problem I am having is due to the way light interacts with end-grain in wood
(it looks darker.)  This makes the edge of plywood have darker looking plys
between plys that are the same colour as the plywood surface.  Further, those
same dark plys on one edge are light on the adjacent edge (and the light ones
are dark.)  The same really goes for pretty well any wood but it is quite
obvious with plywood.

Thanks,
Mike

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Le 28/01/2011 05:27, Solar Mike nous fit lire :
> I'm trying to model a plywood texture and was hoping someone here would have
> some insight for me.
> 
> The problem I am having is due to the way light interacts with end-grain in wood
> (it looks darker.)  This makes the edge of plywood have darker looking plys
> between plys that are the same colour as the plywood surface.  Further, those
> same dark plys on one edge are light on the adjacent edge (and the light ones
> are dark.)  The same really goes for pretty well any wood but it is quite
> obvious with plywood.
> 

Not all plywood, not every cut.
Darkness/lightness is due to the orientation of the fibers in regards to
the cut.

Use the cubic pattern at the root of your texture.
Then for each of the 6 faces, provide the pattern that you want
(including a shifted pattern for the adjacent edge, or a reversed map...)

Scale & translate the cubic as needed.

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Le_Forgeron <jgr### [at] freefr> wrote:

>
> Not all plywood, not every cut.
> Darkness/lightness is due to the orientation of the fibers in regards to
> the cut.
>
> Use the cubic pattern at the root of your texture.
> Then for each of the 6 faces, provide the pattern that you want
> (including a shifted pattern for the adjacent edge, or a reversed map...)
>
> Scale & translate the cubic as needed.

Thanks for responding.

You are quite right about not all plywoods working this way and is indeed due to
the fiber orientation.  I was hoping to find a more general solution as many of
the pieces I have will have curves "cut" in them.  This problem shows itself on
plain (but curved) pieces of wood I am trying to render as well and I have not
figured out a good way of dealing with that.

Typically, I see these issues when doing CSG operations.

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Le 28/01/2011 19:05, Solar Mike nous fit lire :
> Le_Forgeron <jgr### [at] freefr> wrote:
> 
>>
>> Not all plywood, not every cut.
>> Darkness/lightness is due to the orientation of the fibers in regards to
>> the cut.
>>
>> Use the cubic pattern at the root of your texture.
>> Then for each of the 6 faces, provide the pattern that you want
>> (including a shifted pattern for the adjacent edge, or a reversed map...)
>>
>> Scale & translate the cubic as needed.
> 
> Thanks for responding.
> 
> You are quite right about not all plywoods working this way and is indeed due to
> the fiber orientation.  I was hoping to find a more general solution as many of
> the pieces I have will have curves "cut" in them.  This problem shows itself on
> plain (but curved) pieces of wood I am trying to render as well and I have not
> figured out a good way of dealing with that.
> 
> Typically, I see these issues when doing CSG operations.
> 
> 

Have you then checked the slope pattern instead ?

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Am 28.01.2011 19:05, schrieb Solar Mike:

> You are quite right about not all plywoods working this way and is indeed due to
> the fiber orientation.  I was hoping to find a more general solution as many of
> the pieces I have will have curves "cut" in them.  This problem shows itself on
> plain (but curved) pieces of wood I am trying to render as well and I have not
> figured out a good way of dealing with that.

I'd suggest some nested construct:

Use a high-frwequency gradient pattern to simulate the layering of the 
plywood, alternating between two differently oriented versions of the 
main texture, depending on Y coordinate (presuming your plywood board is 
in the XZ plane).

To simulate the orientation dependency of the texture within each 
plywood layer, use a radial sine_wave frequency 2 pattern to blend 
between two textures with different brightness and whatever other 
properties you may want to vary.

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Le 28/01/2011 20:30, Le_Forgeron nous fit lire :
> Le 28/01/2011 19:05, Solar Mike nous fit lire :
>> Le_Forgeron <jgr### [at] freefr> wrote:

>>> Scale & translate the cubic as needed.


>> Typically, I see these issues when doing CSG operations.
>>

Have a look at p.b.i & p.b.s-f for a small test in gold.

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Le_Forgeron <jgr### [at] freefr> wrote:
> Le 28/01/2011 20:30, Le_Forgeron nous fit lire :
> > Le 28/01/2011 19:05, Solar Mike nous fit lire :
> >> Le_Forgeron <jgr### [at] freefr> wrote:
>
> >>> Scale & translate the cubic as needed.
>
>
> >> Typically, I see these issues when doing CSG operations.
> >>
>
> Have a look at p.b.i & p.b.s-f for a small test in gold.

Thanks,

I think slope was pretty well what I was looking for except that I was hoping
the direction vector given would get transformed along with the object it was
applied to.  As your scene points out though, having light and dark layers
provides a pretty reasonable approximation. :)

Mike

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