Aug 18, 2010

Quotation "Premultiplied vs. Un-Premultiplied Color Channels"

quote from Technical Introduction to OpenEXR.
Premultiplied vs. Un-Premultiplied Color Channels
The A, AR, AG, and AB channels in an OpenEXR image represent alpha or opacity: 0.0 means the pixel is
transparent; 1.0 means the pixel is opaque. By convention, all color channels are premultiplied by alpha,
so that
composite = foreground + (1-alpha) × background

performs a correct "over" operation.
Describing the color channels as "premultiplied" is a shorthand for describing a correct "over" operation.
With un-premultiplied color channels "over" operations would require computing
composite = alpha × foreground + (1-alpha) × background

"Premultiplied" does not mean that pixels with zero alpha and non-zero color channels are illegal. Such a
pixel represents an object that emits light even though it is completely transparent, for example, a candle
flame.

Aug 13, 2010

Mesh Motion Blur Defomer for Maya

I made a motion blur plug-in for Maya in previous project.

Aug 6, 2010

A particle trail node plug-in for Maya

I've made a particle trail node plug-in for Maya.
It has been adding new function and fixed bug.
It has an error when using Mental Ray batch render.
Error: (Mayatomr.Geometry) : unnamed object is not a mesh, ignored Fix it.
I might release it.

Aug 2, 2010

Sine wave pattern

A sine wave pattern expresses:
position = (sin(frequency * frequency multiplier) * amplitude) + offset