Energy Aura Effects

[StarfishRap]

Hello everyone,

I'm trying to get the effect that is being shown in a lot of games trailer.

The energy aura effects. Below are reference images, there's more but these should be enough to covey the idea.

Here are some of my experiments.

Particles driven sprites, multiplying and adding to each other to get the glow.

Shader credits to Mr Ron Bernard.

Someone please shad some light on this topic?

Is there a good way of controlling the intensity?

Besides lowering particles count.

I tried to using the clamp but it tones down the whole thing and not just the brightest part.

How is the nice soft wavy lines being formed and how is it being shaded?

Would like to make a sword swing and have those effects trailing after it.

eneffect_rnd_v000.hipnc

[Andz]

Hey Starfish,

I don't know how much of this you really need to be done inside the rendering engine, but usually I'd do these type of glows all in post , rendering out separate passes for the particles and using some simple motion and gaussian blur filters and a additive passes.

[mightcouldb1]

For those kind of energy trail effects, you could do a low res fluid sim and advect particles through it... or you could use some low frequency noise. Make sure you have lots of small particles at a low opacity.

[StarfishRap]

Thanks for replies,

My aim is to get it look good in houdini and enhance it in post

Not quite sure what passes and how to set them up.

fluid sims sounds like a good idea but I'm still new to fluid, is there a good tutorial/doc to help me get started?

I'll try emitting a lot of particles with low opacity and some noise in pop network for now.

Thanks!

[postezz]

you can also consider using geometry, i've done similar stuff with SOPs and the lava shader (you can import it from H10),with animated displacements and motion blur.

[StarfishRap]

Does anyone know the expression to scale my sprite from small to big and then back to small?

$LIFE + something or multiplying to something will only make my sprites keep growing.

[old school]

Use the old smooth() - smooth() technique.

smooth($AGE, 0, 3) - smooth ($AGE, 5, 7)

smooth() returns an ease curve from 0-1 over the range indicated.

So to read the above expression is:

Take $AGE and from 0 to 3 seconds, go from 0 to 1 using an ease function.

Then from 3 to 5 return 1.

Finally when $AGE goes from 5 to 7 seconds, subtract a value from 0-1 from 1 to get back to 0.

An example using $LIFE could be:

smooth($LIFE, 0, 0.2) - smooth($LIFE, 0.8, 1)

If you were to read Advanced RenderMan or any of the shading books, the above expression is key in getting an aliased pulse train going.

[StarfishRap]

Alright man! Thank you very much!

Thanks for the explanation instead of just posting the expression to use.

Edit: Just to share with anyone that's using this expression and finds that sprites is not getting big enough.

I'm using a fit01() to get a new maximum value so that $LIFE could reach new height lol.

fit01(smooth($LIFE, 0, .3) - smooth($LIFE, .5, 1), 0, 2)

The above expression enables my sprites to grow 2 times the size compare to the default.

If you want to make it smaller just change the max value to something lower than 1.

fit01(smooth($LIFE, 0, .3) - smooth($LIFE, .5, 1), 0, .4)

Edited March 24, 2011 by StarfishRap

[StarfishRap]

Hi all

Just a little update and problem.

I've change my sprite to a simple circle with soft edges.

Now I'm getting the light streak like I wanted but there is problem during the start and end of the streak.

In other words not enough particles hence a gap in between sprites.

Things that I've tried:

I've tried increasing sprite size by a ramp where during birth the point 1 and 2 have a big jump and then smooth it out.

ropout the particles, file in, timeblend, time shift. Not quite sure how timeblend/timeshift works.

Oversampling the pop network, but I heard that it doesn't work with constant birth rate?

Motion blur is turned on but doesn't work.

particlesTrail.hipnc

Thanks for your time.

Edited March 28, 2011 by StarfishRap

[pclaes]

You could turn it into a line, and render it as a curve instead of sprites. Looks more like motiongraphics that way.

You make the line with a trail or add sop, you then resample the line a bit if you want. You convert the line into a nurbs surface to get it smooth.

You delete the last 4 points of the line as they will give you incorrect results. You uv texture them based on rows and colums.

You add a width attribute to them that will be picked up by mantra. You map your opacity and color over uv.... kinda like a hair shader.

You can have the attributes such as "v" inherited from the points so you get all kinds of crazy motionblur similar to fractals.

The trail otl on this dvd (bonus) can make images like the final fantasy ones pretty easily:

http://www.3dbuzz.com/xcart/product.php?productid=58&cat=0&page=1&featured

or do a search on this forum for "trails".

[Sean Lewkiw]

Use an add sop to create lines, (you can use nulls as sources for the points so you can animate/track them), resample to increase point count, then noise to randomize it, then copy L-systems (lightning) off each point using stamping to get varying lengths, seeds, etc. These can also be procedurally animated using stamping. Then use the polywire sop to make them into a contiguous mesh. Finally, you can use this as a light source, and it will auto-light your scene!