[Bf-committers] Wood texture update
Chris Burt
desoto at blender.spaceisbig.com
Sun Feb 27 06:10:53 CET 2005
By popular demand, a comparison:
http://blender.spaceisbig.com/old_wood01.jpg - Official 2.36
http://blender.spaceisbig.com/new_wood01.jpg - My Build
*Identical* blend file. Blend file created in 2.36 *then* opened in my
build and rendered with *no* tweaking. Not fantastic, but also only
represents about 3 minutes of work.
Let the critics decide?
Regards,
--Chris "Trying to sell wood to the masses" Burt
Chris Burt wrote:
> I've been doing some work on the wood texture to find some pleasing
> results. The previous implementation relied on a periodic function to
> produce the output values of the wood texture. The end result of this
> implementation were unavoidable symmetrical intensity bands. The problem
> with this approach is that trees do not have a sinusoidal growth
> pattern. They grow faster in one season than another,except for in
> climates where growth is supported year-round. Thus a quick glance at
> the grain of any piece of wood generally reveals sharp contrasts between
> the end of one season of growth and the beginning of another. While you
> might attempt to reproduce this effect with colorbands, you would fail
> miserably because no matter how hard you try, the intensities returned
> by the current wood texture code would only let you control the
> appearance of 6 months of the year, the latter 6 months being a mirror
> image of the first. This is illustrated here:
>
> http://blender.spaceisbig.com/old_colorband_wood.jpg
>
> In this image you see the colorband, which, given any piece of wood,
> should represent one year of growth. The yellow color marker represents
> the month of June, and the red color marker represents the month of
> December. (Note: These are just examples for simplification. From an
> artistic standpoint it doesn't really matter what "month" the cursor is
> in, only that the entire color band represents one year of time)
>
> http://blender.spaceisbig.com/old_wood.jpg
>
> In this image you see the resulting wood texture as rendered on a plane
> in Blender 2.36. It is easy to see in this image that the month of
> December actually falls where June should fall, and that the last 6
> months of the "year" are simply a mirror image of the first half of the
> year. The results aren't nearly as realistic in my opinion. However,
> when you have proper control over the entire "year" you get results more
> like this (the result of some quick fiddling before lunch):
>
> http://blender.spaceisbig.com/new_wood.jpg
>
> I hope that you all agree this is a more realistic looking texture. I
> know I haven't created a side-by-side comparison but I hope you can see
> the usefulness has been improved.
>
> The good thing about this new implementation is that the intensity
> values can be made to look like the old system simply by putting the
> same color marker at each end of the color band. The result is nearly
> identical.
>
> Some questions for discussion:
>
> 1) Are the normals created by my technique accurate? (Probably not).
>
> 2) How should this be implemented in the UI? Right now I think it would
> be best if there were a way to use the old method as well, as my method
> is certainly slower.
>
> 3) Is there another way to achieve the same result without resorting to
> using the modulus function I've adapted from "Texturing & Modeling; A
> procedural approach"? It requires a sawtooth output in order for the
> user to have complete control (in my opinion.)
>
> 4) Should the "ring" versions have 3 dimensional components? Trees are
> cylinders, not spheres.. thus the code creating the output shouldn't be
> producing spherical rings in my opinion. I had trouble creating
> realistic results by simple disabling the Z-mapping. Maybe someone has a
> better idea for this?
>
> 5) Is this email too long to bother reading? ;)
>
> Thanks everyone for your input! (Those of you who give any ;)
>
> Regards,
> --Chris
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> Bf-committers mailing list
> Bf-committers at projects.blender.org
> http://projects.blender.org/mailman/listinfo/bf-committers
More information about the Bf-committers
mailing list