I'm currently trying to reimplement some more or less important features of current particles and have some questions that should be discussed. These are regarding issues with the emission procedure, which will be much more flexible with paged buffers, but also break some simplifying assumptions that make the current system work.
The new code can be found in the particles-2010 branch, more info can be found in the wiki: http://wiki.blender.org/index.php/User:Phonybone/Modular_particle_system 1) Jittered and Grid distribution: These depend on a fixed amount of particles to avoid repetition (or at least determine how many particles can be emitted before the pattern repeats). This was no problem with the current fixed-size buffers and their inherent "amount" value. The new rate-based emitter mode does not have such an upper limit. It could either disable these distributions or provide an arbitrary user defined number. Emitters will also have "amount" modes, where a fixed amount of particles is emitted over a frame interval or right at simulation start (useful for hair with infinite lifetime), these modes can still make use of jitter and grid distributions naturally. 2) Hair emission and lifetimes: Currently hair particles are basically treated as "paths" of their root particles. This means that when hair is calculated initially, the normal particles are simulated over (arbitrarily) 100 frames and their locations used as keys for the hair particle strands. This is not totally wrong, since it somewhat resembles the process of hair or grass "growing" out of their roots (which in turn are located in earth or skin, represented by mesh surfaces). Good hair geometry usually needs a lot of modification in particle edit mode afterwards. Actual dynamic hair behaviour is done with a completely separate system, which interprets the "finished" strands as cloth (and has its own problems, see Durian). I'd like to somehow make a separate simulation step for initial hair growth to avoid fast-forwarding the whole particle system through the 100-frame lifetime of hairs as it happens now. This would probably cause trouble, since particles can be emitted in any frame now, so they can't be pre-calculated at simulation start. A quick solution could be to just disable emissions other than "all at the same time" for hair. Any opinions? _______________________________________________ Bf-committers mailing list [email protected] http://lists.blender.org/mailman/listinfo/bf-committers
