View Full Version : LW 9 vs 8.5 render time!

07-21-2006, 02:30 PM
Hello. Im new to this forum. Upgrade Lw8.5 to 9. I test render times on G5 dual 2Ghz / 3 Gb ram / 10.4.7 / multithread set on 8, it' seem ok on activity monitor.

LW 9 is 10% slower, tested on lws benchmark : dof, rrt, raytrace, tracer (no) radiosity.... (addition of total time test).

raytrace : lw8.5 = 55,7 sec / lw9 = 89sec (+60%)!!!
tracer radiosity : lw8.5 = 307sec / lw9 = 362sec (+17%)
no shorter times than 8.5!!

With personal scene : raytrace + radiosity. Time : LW8.5 = 100% LW9 = 187%! ;-((

I hope i forgot simple adjustments.

any idea?

07-21-2006, 03:47 PM
Use the perspective camera. That has the new raytrace engine behind it. The classic camera is there because the new engine has limitations (including 1 and 2 point polygon support). You should find 9.0 then renders faster.

Note also that the perspective camera works best when you set the number of threads to be equal to the number of CPUs you have (i.e. 2 in your case).

07-21-2006, 05:01 PM
I just read the pdf,

""Similar to the Classic Camera, however there are some differences to note. The Perspective camera renders from the top of the frame down and complex scenes tend to render faster. More information to come. Points and Lines do not currently render with the Perspective Camera.""...

but no changes!!

07-22-2006, 03:17 AM
There's a few points to note here. Firstly LW9 seems to work best with threads set to the number of processors you have so having threads set to 8 on a 2 processor machine will probably slow it down. It's worth experimenting though!

Second the Perspective camera is not necessarily the fastest. In complex scenes with millions of polys and/or intensive ray-tracing the perspective camera should be fastest, sometimes many times faster than classic. In simpler scenes though the classic camera will be faster than perspective camera.

Thirdly, yes, unfortunately some scenes will render faster in LW8. The raytrace.lws in content is one. The reason is the prerendering operations are more complex in LW9 (KD tree I believe) this slows down simple scenes but they allow the rendering of complex scenes much faster.