View Full Version : particles go crazy on higher gravity values

08-23-2008, 05:00 AM

i'd like to make a little rain effect with particles, so i added a wide emitter over the ground producing a few partcles, a child emitter to that emitter having nozzle parent emitter (end), a little vibration and an upwards acceleration. i added a huge collision box at ground level and and a global gravity.

the particels it self are hypervoxel surfaces, scaled along velocity.

when i set the global gravity of -9.8, the child emitter goes completely crazy, it draw lines between different child emitters for one frame.

when hitting calculate, everything seems fine. as soon as i render a frame, the lines show up. you don't see them in layout, unless you select the child emitter.

heres the result rendered out:


i spent a lot of time searching for the problem and noticed, that, if i reduce the gravity to something like -2, it works fine, but ofcourse does not look very realistic, here is the example:


whats going on there, anyone hade this problem and found a solution?

thanx for any help,

08-23-2008, 11:19 AM
i am getting a bit closer.

the problem seems to be related with velocity y of the child emitter. if i make velocity y bigger than about 75% of the negative gravity, e.g. velocity y = 7, gravity = -9.8, then this dont happens anymore

ofcourse then the rain splashes jump high in the sky, which is not what i want.

i think my problem is coming from the fact, that the particles of the child emitter created with nozzle 'parent emitter (end)' seems to get the current velocity of the just died parent particle applied on creation. how can i prevent this?