[Bf-committers] Problem of Rendering Speed

[Yaohua Xiong]

Hi everyone

I'm doing a traffic visualization project using blender
2.5svn(details:
http://blenderartists.org/forum/showthread.php?t=161741&page=2) and
having some problem with rendering speed.

I represent the vehicles in blender using two methods.

1. every vehicle is represented as an individual object(sharing the
same mesh) and use key frame move the vehilce
2. vehicles are represented as a particle system, one particle for
each vehicle. The trajectory of particles are load in using external
cache file. every particle render as an object.

The basic scene is the same for these two methods(2011 vehicles, 600
frame) but the rendering speed is very different. The rendering speed
for the first method is about 30 seconds/frame which I think quite
normal but the render speed for the second method is about 15
minutes/frame, it's 3000% slower!

The real strange thing is that about 14 minutes of the 15 minutes is
spend on the "Filling octree" phase of render, but the number of
objects should be the same for both methods(2011 vehicles), what makes
the difference in render time and how this can be improved? Anyone got
an idea? Thanks in advance.

-- 
Yaohua Xiong

Traffic and Transportation Engineering College, Tongji Univ.
Cao An Road 4800#, Jia Ding District, Shanghai,  China