Blender 2.74: Cycles
Cycles improvements include: Ray/Triangle BVH building is now watertight, a new QBVH tree traversal structure, various optimizations especially great memory related ones, a new pointiness attribute for the Geometry node, controlling of an object's texture space by another, ...
- Ray/Triangle intersection is now watertight. This is expected to address quite a reasonable amount of reports from the bug tracker, plus it might help reducing the noise in some scenes. (f770bc4757a2)
- Implementation of a QBVH optimization structure for CPU with SSE2 support and above. GPU rendering, non-SSE and 32bit processors still using regular BVH. (03f28553ff07)
- Optimize black world backgrounds (cd723967970e)
- Optimize vector math node without links to a single value node. (43421e9c5354)
- Reduce lag between shader tree modification and viewport render (2dfe5e3)
- Fallback to bottom-top tile order when rendering from the command line (bb08502)
- Optimize memory usage when creating mesh attributes (1862fbf)
- Reduce memory used by background light update (0f65250)
- Optimize memory usage during BVH construction by freeing memory used by intermediate BVH vectors earlier (3bc9ac1)
- Added attribute indicating how "pointy" the geometry surface is. Available via "Pointiness" output of the Geometry node. (227a940)
- Added support for texture mapping from another object (df07a25).
- Image texture node now supports sphere and tube mapping. (12ccac6, dda3554)
- Cubic image texture interpolation is now available on CPU (previously only for OSL). 3b9d455
- Cycles now uses clipping plane instead of clipping sphere (54fd3f3).
- Added field-of-view options to the equirectangular panorama camera (4118c1b).
- Ignore preprocessing time in ETA calculation (193871a)
- Use lower progressive update timeout for preview rendering, gives more instant material feedback (888d810)
Forward compatibility breaking
There was an old bug with Mapping Node in Cycles which gave totally different result than Blender Internal and GLSL/Material viewport shading. it was caused by the flipped euler order in Cycles.
It is now fixed (a1ffb49), but if this node is used, opening newer files in older blender will give incorrect results.