I'm kind of embarrassed to ask this, but I've always wondered. What exactly is the difference in the optimization choices under render options? See attached pic as reference to what I'm asking. I know I could look it up, I'm being lazy. :-P Second question - which do you normally use and why?

I use Clustered scenes....why? I heard that it was best for scene with lots of objects.....

Personally, I haven't a clue about that one. Perhaps the renderer can handle calculations a bit better if it's given an idea of the type of scene. Good question though - I only wish I knew! Len.

Anyone else? I'm very curious as to this option.

"Clustered scenes" are those with close together and/or overlapping objects.

"Uniform scenes" are those with objects spaced wide apart fairly evenly over the Bryce 'grid'.

I use the former 'cos that's what my scenes usually consist of (plus it's the default! ;-)).

Thanks, PJ. I use the clustered myself.
My scenes definitely tend to be overlapping in a myriad of places. :D

Back to the basic question... WHY? WHY does it make a difference to Bryce if you have it set one way or the other?

It USED to make a difference...back when computers were measured in mouse watts..instead of gighz (heh) with todays processors and ram, I dont think this makes a whole lot of difference anymore...and like the legacy ctrl+alt+shift+click the minus thingy in Bryce..its just never been updated or changed. :) BT

Ah-HA. So that's where it came from! Many thanks BT for stopping by to solve the mystery. I'm so glad to see I wasn't the only one who was lost as to this option, lol. ~arry :)

Optimisations have been changed and updated - the BSP and Grid options were new to Bryce5.

Previously (from Bryce2, not sure about Bryce1) the three options were: Spatial Optimisation off; Spatial Optimisation low; and Spatial Optimisation high. Now we get the two new ones, each with the three levels (renamed and maybe reconfigured).

As to WHY. Well, as my mother used to say to me, "Because I bloody well said so, that's why. Now... be - quiet!" But that was last week. This week:

I think it's to do with Bryce having knowledge of where objects are in the scene and using that knowledge to not waste time sending rays to where there are no objects. So, depending on the layout of objects, Bryce uses different algorithms to trace the rays.

The pic above shows the results from the different algorithms rendering the same scene (a bunch of stuff close together and overlapping, lit by the sun and a radial light). As you can see, the time saved by using the correct optimisation setting makes a substantial difference (about 20%) - even with a simple scene that renders quick. Note the excess ray hits and misses with the Grid setting.

With an animation or a scene that takes hours to render, 20% is not to be sneezed at (assuming a linear progression).

I had intended to post an example showing the benefit the other way, but I'm not sure I know what the engineers mean by a "uniform" scene. What I thought fitted the description resulted in an even bigger advantage for BSP, so either I've got the meaning wrong or the Grid setting is completely frelled.

God I'm sad.

Attached Link: http://www.geocities.com/SiliconValley/2151/bsp.html

And to elaborate, here are details about binary space partitioning (BSP) so that it will make a bit more sense, and take the mysticism out of things... I'm not certain how the "grid" method works in Bryce though. I suppose compared to BSP it merely works off of grid-space instead of binary space?

So that's what "BSP" stands for. LOL, never would've guessed that! Thanks for the link and off to take a look......