Started to learn Krakatoa…

Quick question:
(couldn’t google this out)

Is it possible that I have 2 (or more) Pflow setups with different Krakatoa render settings (density, voxel/particle shading)?
For example, Pflow001 with million particles, and another with 5000 particles with voxel shading, and all render at once.
I know I could do it in post, but for some quick tests it would be great if this is possible.

One more questions while I am here:
Anyone knows how Mattias animated Krakatoa hair in this video?
(15 seconds).

Thanks in advance. :slight_smile:


Krakatoa has these channels per particle, so you can render them if the particles contain the data. You can either write them with box3, or cache the pflow to PRT and then assign the channel data with a magma modifier.

Looks like wind turbulence.

jiveli! :wink:


While you can control the Density per system (even directly from PFlow), you cannot mix particle and voxel rendering at the same time. They are two completely separate render engines and need to be run in individual passes. A lot of people use both to produce more detail through particles and a more pyroclastic look through the voxel pass, but then they have to be comped in post.

Regarding the channels, there are so many ways to control the Density per particle that I am not even sure where to start. Keep in mind that any Standard Material assigned to PFlow particles will multiply the original density (1.0 per particle) by the Opacity channel (thus allowing Opacity Mapping).

You can also set the Visibility of any particle source to less than 1.0 (although this is a bit tricky with PFlows, but it is possible).

You can also provide a Density channel directly using the Krakatoa Options operator. You simply have to check “MXSFloat->Density” and then set the Scripted Float channel accessible through the Box #3 ops or Scripted Ops to a per-particle value.

Or you could save your PFlows to PRTs first and then use Magma to control any channels by any other channels or data…

When that video was made, Krakatoa did not support Hair rendering, but Matthias just used spawning of particles to simulate something that looks like hair. In Krakatoa MX 2.x, you can use the PRT Hair object to turn any spline or all scene Hair&Fur to particles - we have videos showing this from 2011’s Siggraph…
(part 2 and 3 are linked from that page, too)
The current workflow is somewhat improved, but the videos still give you an idea.

It was used to render the CG hair on digi-doubles in the SuckerPunch bullet train sequence for example:


Hey Hristo, thanks man :slight_smile: , and - živeli! :beer: :slight_smile:

I’ve looked at some tutorials for magma flow, and gotta admit that I was a little scared with all the options in there, so my question was some quick way (if possible) to make different setups for a different particle flow systems.
Anyway, what have to be done, have to be done, and when I find some free time, I’ll take a careful look at default Krakatoa tutorials, and slowly, I will learn.

Hey man, first of all: it’s very commendable that you always find time to give a precise answer, even for noob questions like mine. As I said to Hristo, I’ve gotta browse through default Krakatoa tutorials, so I find answers to my noobish questions.

However, your answer is very helpfull for my early tests, and I’ll try what you suggested (reducing Pflow visibility (if you mean Pflow-object properties)).

I’ve made a mistake, because I didn’t explained what exactly I wanted.
I wanted to make something like rich starfield, with different nebulas and stuff. Now, let’s say I want to use just voxel render engine (because I am able to change the size of the voxels).
Is it possible that I change the voxel size and blur properties for different Pflows? For example, first Pflow is just the stars, second is bright stars, third (with blur increased) is nebula… etc?

For the end, here’s my first play with Krakatoa render (and some bad post :slight_smile: ).

Thanks to all :beer:


Zdravo, Bobane!

Let me start by saying that your first video is one of the best first-time Krakatoa tests I have ever seen. YouTube is full of bad “first Krakatoa tests” and I was very pleasantly surprised!

The voxel size is completely fixed. You cannot control the Filter Size (which controls the blurring) per voxel or per particle. So no, I would not use Voxel rendering for what you described (but you might find a way to comp multiple voxel renders together, so I won’t tell you what to do, I am just saying what I wouldn’t ;))

The best nebula tests I have seen (like the Matthias Mueller “The Space We Live In”) were done using particle rendering.

Also, the latest version of Krakatoa provides the Repopulation feature which lets you turn a few particles into blobs of particles, or replace each base particle with a cluster of other particles via the Krakatoa PRTCloner modifier. I would start with the basic distribution of the stars and then try to use the PRTCloner to make them look like larger and smaller spheres. There is a lot of control over the size (scaling) of the individual clones, their colors and all other channels.

Just some ideas.


Hey Bobo - Veliki pozdrav i živeli! :slight_smile:

Thanks a lot for the kind words, I hope my tests will be better in the future, and I’ll keep learning stuffs. Also, thanks for your ideas, they are very helpful.

Yeah, Matthias is awesome, and I keep re-watching his tests over and over again, and also, trying to not copy him when doing my tests, which is very hard, because his tests looks really awesome, both in terms of shading, and motion.
Actually: It is hard to copy him, and it is hard not to copy him :slight_smile: … if you understand me. :slight_smile:
I also like very much his test: Protos star formation.

Cheers :beer:


Anyone know how i can tell Krakatoa to render different colors for three different pflows but without comping it in post ie all in one render?


Krakatoa used to respect the PFlow Display operator color. Is that not working?


yep it is! i asked a question without thinking about it or trying first…but as i was conceiving the concept…cheers Random


Oh good. There was a build that didn’t respect the display op, which is why I asked :slight_smile:


is it possible to write data other than color and density from box#3. I can create the other channels at render time using magma on a prt loader but I am thinking it would be more efficient writing the data to 500 000 particles when partitioning. searching for a closest point on 50 000 000 particle is really slow.




Just after a while testing new krakatoa version for maya.
Main issues which should be explained in quickest, which are sort of not intuitive to figure out are:

  1. How to render image sequence at all ?
  2. How to change shadows (color, intensity, etc) on lights ?
  3. How to get free version for life ? What I need to do ?

Bobo, can you help ?
And yes. I see. Krakatoa Maya, finally arrived!! :slight_smile:




Let say, I have parent particles in Event1 with LifeSpan 0-100, and Spawn Particles in Event2 with LifeSpans=20, when I use age ratio to drive color gradient, there is taken into account 1st lifespan but not spawned particles, how to solve this problem?


Are you resetting the particle age when you spawn? I think there is a check box for this in the spawn OP.try turning it off.


Heh, I remember it was ON, it seemed to me that it is right


I saw this question asked over on the Thinkbox forums, but it never got a reply. After searching high and low, I turn to you good folks.

Is there a way to “tag” a particle once it has been selected in Magma flow?

I have a simulation where particles will be selected once their velocity is below a certain value, then a Delete modifier ontop of them to get rid of them.

However, at a later point in the sim, they pick up velocities again, and are thus not selected and re-appear.

Is there a way to essentially tag them once they’ve been selected once so they will stay deleted?


Hi, getting color issue with krakatoa magmaflow. Color looks perfect in viewport
but at render time don’t know why yellow tint comes instead of white

Here is magmaflow connection

Here is Render output and Viewport snapshot


Check if you have a colored light or absorption enabled.


Having only one spot light with white color & absorption is turn off.

Found reason behind this

In input Vector node,Complement color is problematic. Now tell me what is the solution for this?


The complement color is just there for a reference, it’s not being used in the rendering. Post your scene so we can take a look.