[Bf-committers] 2.28 Ahoy 2!

Nathan Vegdahl bf-committers@blender.org
Thu, 24 Jul 2003 02:31:02 -0700 (PDT)

> - the commits you did for this system were so many, that I could not  
> locate all changes for it. So I've loaded tuhopuu.exe, checked what I  
> liked from it, and started over from scratch.

   Heh... yeah, I wasn't very good about that. :-/

> - Yep, I completely forgot about the texture channels for it. A nice  
> addition for a 2.29 release!

   Yes, I suppose people can just use tuhopuu if they need to until then. :-)

> - The buttons layout you did in Tuhopuu really was messy, with buttons  
> crammed together below a minimum acceptible size.

   As I said: my vote doesn't count, because I'd be biased. :-)
> we now really need a method to expand buttons easier. Proposals for  
> that are being discussed.

   Cool.  I look forward to seeing what you guys come up with. :-)

> - I found some tuhopuu code that related to shader plugins, but could  
> not find clues how it was supposed to work.

   Yeah... I should have commented it better.  Sorry about that.  I'm rather
bad at commenting when I'm not programming from scratch. :-/

> Apart from that, I don't even *know* if we want it in bf-blender. Plugins in
> the past (texture, sequence) only have given us troubles. My preference is to
> look first if we can do this with Python. The python coders already
> investigate feasibility. Then at least we have something stable & cross
> platform.  I am very confident the current implementation can easily be
> tweaked  for such plugins. Let's first discuss & research this topic!

   Hmm... I don't really see a point in implimenting it if it wouldn't be used
in bf-blender.  I think I'll hold off on implimenting it until you do know.  In
the mean time, I have other things I want to work on in Blender.  Of course,
that will still have to wait until school starts...

> - Blender already used the 'hardness' value to determine specular size.  
> I decided to copy that for Blinn, since it works almost the same. I  
> transformed the hardness integer value to a float, with a formula  
> that's close to what Phong and CookTorrance offer. The 'roughness' you  
> provided in Tuhopuu was impossible to work with... with a slider which  
> offered the most interesting results in the lower 1% of the values.
> I realize what i did is not 'scientifically correct'... it was just a  
> quick decision, with the aim to make something that worked. I also  
> didn't know the Blinn roughness was tied to Oren's roughness. In all  
> articles I read about it, I couldn't find a reference for it.

   It's never stated directly anywhere that I know of, but if you read both
papers, you will notice two things:
   - they both use the micro-facet surface model as their basis
   - they both use gaussian distributions as the statistical micro-facet
distribution model.
   Because of that, if they are both given the same parameters, they will both
be representing a surface with identical properties.  Which, of course, is why
it's ironic that in 3D-studio max the two distribution parameters don't
correspond to each other.  I suppose I was trying to out-do them. :-)
   I still think that the Blinn parameter should be reverted to how I had it,
but I'll leave that to your descretion.

> Again, no harm done if we decide later on to change it. Blender  
> filereader can convert it.

   Oh!  I forgot about that.  Yes, of course.

> Cessen, I really liked your idea to improve the shading in Blender, and  
> the code for the math was extremely welcome. I will be glad to further  
> work with you on this, and come together with improvements for further  
> releases.

   I think one thing we can do to improve it is to simply add more shaders for
people to use.  The more flexability, the better! :-)

--Nathan "Cessen" Vegdahl

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