Krakatoa particle rendering

#1

I’m using Krakatoa to render my PFlow driver by fumefx.
I want the PFlow render result looks like the outer spaces in Clash of the Titian 's intro.
But to many small dots make me crazy .
If I turn final pass density down to about 1 and set Density Exponent down to about -5.
There so many small dots show on my render screen.
But if I turn the final pass density and Density exponent back to 5 -1 .
the result shows to much density like cloud.

is there some other way to render my outer spaces much more like the Clash of the Titan’s?
Or there some other problem with my scense? like camera , lights …etc.

Thanks in advenced.

#2

Your density settings are probably going to change a lot depending on things like the number of particles and the size of your scene. Some pictures would help for specific issues . :slight_smile:

There is quite a lot going on in that sequence, and it looks like a something best done in layers and comped together as no one setting will work for everything.

The big, bright stars could be done with low particle counts and voxel rendering mode. The ones closer to the camera will get bigger to give a good sense of depth. These can be treated in post to break up their shapes.

A nebula would use more particles with less density to let them blend together. You can make them glow by using emission (kind of like turning each particle into a light…if you control it by age you can get clouds that are cooling off).

For very bright formations with a lot of energy you can try force-additive mode. This will let you see through your cloud and brighten up areas with more particles (can look very nice with detailed fume or phoenix sims). Be careful with this as it does not provide alpha or z depth passes so it can be harder to comp.

Good luck…hope this helps,
CZ

#3

I have try to use krakatoa only save particles and render it last night.
the thought is use prt loader only load one prt file and hold it to render
and the motion controls by camera.the particles just stay where they are.

the result its nearly my final result.

If I use force-additive mode.
Can I just turn the ptl or Fume to White,the BG goes to Black.
just use the color channel as alpha channel.
Will it wokes well?

Thanks.
Your reply is very helpful.
CZ.

#4

Yep, loading a single frame of the cache into a PRT loader should give you a formation that will stay in the same place and you can fly around it without having it change. If the particle count is low enough you can use the pcache button next to the big render button and not have to reload the data every time you test render a frame.

You can absolutely fake an alpha with force additive by using the luminance of the rendered image over a black background. However you do have to be careful with moving your camera too much as it will become very transparent if you get too close.

Bobo put up a great tutorial for altering the density based on camera distance which could help out a lot with bigger camera moves. It is definitely worth taking a look at if you like the force additive look…
http://www.thinkboxsoftware.com/krak-additive-rendering-zdepth/

cheers,
CZ

#5

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