Peter Q's videos helped me get started with these particles, and after some experimentation I am fairly happy with the result. Just a couple of things I would like help to improve;

1. the shadow seems blocky and does not seem to consider the fine particles of the spray, i.e. the particle uniform scale property and/or alpha (shadows are ray traced via a point light)

2. it seems the particle stream is too “white” at the start - with a solid, eliptical shape - I would like to make this a bit less solid but can't seem to adjust it in any way. It just doesn't seem quite right to me (you can see it clearer in the shadow).

I have attached the scene file; here are the properties used:

Source
Const. birth rate: 750,000
Life Expectancy: 1.5
Life variance: 0.75
Velocity: 15,0,0
Variance: 14,4,4

Render
Particle size: 0.1
Particle blue: 1/$FPS

Colour
Alpha Param: (1 - $LIFE) * 0.5

Property
Uniform Scale: (0.3 * rand($ID) * 0.3) * (1 - $LIFE)

My machine (4gb RAM) chugs a bit with over 1 million particles so I hope the answer isn't too many more particles

Thanks for reading

hi, why dont'you save your particles to disk and load them in a delayed load shader, this can help you in render more than 1 million particles, use point rendering (mantra) and a constant shader with low opacity to avoid the white eliptical effect….maybe you can use a ramp to have more opacity in your birth emission point ($age or $life ??)…the blocky shadow seems a low sampling issue, maybe an area light can help producing softer shadows, or a blur in a separate pass in comp.

Thanks blonde, that gives me a lot of ideas to work with!

Can I ask approximately how many particles you would expect to need for this? 1 million … 10 million … more? Naturally, I need to just keep experimenting until it looks right, but an idea would be useful.

Thanks again,

Mark

Right now I would forget about the amount of particles and concentrate on the properties of the particle. Of note last night happened to use a spray over a surface and it did not cast a shadow onto that surface. So that begs the question for your shot lighting conditions do you even need to bother with creating a shadow on a surface …..

rob

understood Rob, thanks, I'll work on the basics (including further observing how it looks in the real world).

Hi, here's where I have got to. Massively improved - it should suit my purposes!

Video here [vimeo.com] (the vimeo encoding has blurred it a bit) and a still is attached.

(I'll see about the shadow in the actual shot )

Thanks again for the help!

Mark

edit; nm worked it out

hi uniqueloginname, your spray looks nice….maybe you can add some noise to improve it or just simulate you are using it in an outside environment with wind forces acting on it….then i was thinking to fake a standing indoor spray with a volumetric object, so i've posted here a start basic scene only to stimulate alternative ways to obtain a similar result. :wink:
It needs noise inside the procedural shader and more offset opacity to shape it better…and more…

Thanks blonde for your feedback. I am also interested to see your solution tonight. Finding multiple ways to solve a problem makes things interesting.

I did add a wind pop with some noise and the particles ‘drift’ sideways, but i could not get the stream to ‘bend’ which it does in real life. I probably need an expression to make the wind stronger as the particles age, so I tried things like making the wind scale “1/$AGE” but did not seem to work (not being familiar with expressions I was happy to think of this, and disappointed when it didn't seem to work!).

I will look into it more later

Mark