[Bf-committers] Particle experiments - looking for feedback

Alex Mole bf-committers@blender.org
Mon, 03 May 2004 23:41:48 +0100

Hi Leon

It should take about the same amount of time to work out the inverse 
transform and multiply two particle points as it does to transform four 
vertices of a quad [roughly speaking]. However, once the particle has 
been inversely transformed, it will work for every face in the object. 
So for an object with 50 faces, we're talking 2 inverse transforms vs. 
200 forward transforms. I'd say that'd be a speed improvement ;)

I don't know enough about the guts of Blender to say for sure, but AFAIK 
transforms are stored in component {translation,rotation,scaling} form 
as well as a matrix, so you should be able to trivially construct the 
inverse transform.

Again, feel free to ask for advice on this if you want it :)

Keep up the good work!


Leon Turner wrote:
> Alex - I wasn't sure whether transforming the particle co-ordinates /
> velocities to object space would help much, given that I need to cycle
> through many possible deflection objects. What do you think?