# How do you randomise particle size?

Currently I am just making extra drawings to simulate a random size of particle.

However obviously it could be very useful to have a random size, change size over age(not time) etc etc.

Is this possible? I know there is a size module but it doesn’t seem very useful to me currently as it just changes all the sizes constantly and I can’t work out what sort of image input to give it(which is a part b question!).

well i figured how to change size over age (you can do this in the emitter). However I am still not sure if you can start with a random size.

That is what I have done for now(which works fine), but I really wanted a more robust solution, cause it is something which is very useful with a particle system.

Can you put this down as a request for particle system?

Yeah I thought it might be one of the parameters in the Random module, but it’s not one of them. You know what you could do is you could create a few different particle types of different sizes, then randomly assign particle type on generation, this might do the trick.

~Lilly

~Lilly

Okay so I talked to the programmer about it and there’s a way to do it right now. We’ll work at making this easier in the future, but right now it’s possible to do it by using the Size module. If you add the size module BEFORE the emitter (to the RIGHT) then it will use this size upon generation of the particles.

You can plug a Planar Region into the Size module, then set this to be a Line. Then you also need to plug a Peg into the Planar Region, and just use this to set the peg to 1 F (1 field front) so that there’s never a negative size value.

Then in your Planar Region, you can set the minimum size in the P1 field, or by dragging on one end of the line. And you can set the maximum size in the P2 field, or by dragging on the other end of the line. If both values are equal for X and Y, then the proportions will remain consistent.

Sorry it isn’t easier to do right now, what we’ll do in the future is we’ll have an interpolated size in the size module where you’ll just be able to input directly there the min and max size.

Here’s a screenshot showing my network:

http://i790.photobucket.com/albums/yy184/lillybirdsong/Screenshot2012-01-03at120905PM.png

Hope this helps!

~Lilly