particle sprite problem

[blackchicken]

Hello I have little problems with particles. First, I found after half year of using houdini that pop group has random grouping heh, very cool but, one problem. I need two groups, random, for gravity and colour. BUt As you can se fron flip, first 20 frames ok, but after 20 frames all particles are inside second group. Nothing is keyed. Miss I something? I use version 10.0.569, 10.0.465

Second problem is rendering sprites. Why is so blurry? If I render as points, all ok, no motion blur ofcourse in render settings, but sprites are totaly blured. I need perfectly sharp picture. Where is problem? Thanks a lot and nice week

group_problem.mov

stars_help.hip

[mawi]

Hello I have little problems with particles. First, I found after half year of using houdini that pop group has random grouping heh, very cool but, one problem. I need two groups, random, for gravity and colour. BUt As you can se fron flip, first 20 frames ok, but after 20 frames all particles are inside second group. Nothing is keyed. Miss I something? I use version 10.0.569, 10.0.465

Looks like that random use $PT and when particles die and $PT change in combination with preserve groups, things get messy.

A solution is to check the group index below and type rand($ID). $ID is a constant int for each particle that never change.

Just remember that if you need more then 2 groups you will have to multiply your rand function with n_groups. Like so for 4 groups: rand($ID)*4

[blackchicken]

Thanks a lot for repply. Ill try it. What about sprites? Have you somebody problem with blurred sprites? Thanks a lot again

[mawi]

Thanks a lot for repply. Ill try it. What about sprites? Have you somebody problem with blurred sprites? Thanks a lot again

Have you tried to increase the shading quality?

object->Render->Dicing-Shading Quality.