Krakatoa

#1221

ahh not badnews at all. Just glad it was not user error on my part.

#1222

Hey guys… thought I would start learning a bit of krakatoa!

I was just following the KCM colour by vorticity tutorial floating around done by pixelpro. I was wondering what the solution is when the gradient ramp is not running in the same direction of the flow of particles. Ive provided a screenshot just to make it clear :stuck_out_tongue:

Thanks

Screenshot!

edit sorry, i changed it to be based on velocity as you can see in the image, if it makes any difference

#1223

There are many ways to do what you asked for, so I wonder if you have considered going through the examples on the Krakatoa documentation page…

Simplest solution - subtract the Magnitude value from 1.0 to invert it.

More advanced solution - create a Blend operator, feed the Magnitude node’s output into the 3rd slot, connect the current Color and another Color input to the first and second slots and you will have a gradient with two colors. Use Ctrl+W to swap Inputs 1 and 2 to invert the direction of the gradient.

Even more advanced solution - convert the Magnitude output ToVector and output as TextureCoord instead of Color, then apply a Standard material with a GradientRamp map to the particles and use the flags to specify any colors or sub-maps.

See the bottom of this page for an example:
http://software.primefocusworld.com/software/support/krakatoa/magmaflow_fading_off_particle_density_by_age.php

Also be sure to watch the YouTube videos from my signature! They are free!

#1224

Ahhh thank you bobo … shall watch your videos and get to work on allllll the documentation :slight_smile:

#1225

Back again :stuck_out_tongue:

Ive followed the documentation and understand how to flip the gradient on the UV but I still cant get it to flow in the direction of the fluid and map to the velocity or vorticity. Where the blue (for example) would be the more denser and then have the ‘foam’ areas as white. When using vertex colour channel it all goes black :S

I shall try read some more tomorrow… tired :slight_smile:

#1226

Hey

Am I right in thinking that after partitioning a standard particle sequence from realflow (using the noise modifier method) that the new PRT sequence loses the vorticity channel?

Thanks

Edit solved cheers!

#1227

Obviously, if the Vorticity is not specified for output, it will be lost. :slight_smile:
If you specify a Vorticity channel in the Channels To Save list, it should survive.

#1228

:slight_smile: Yea I noticed that especially as a similar post is at the top of this page!

Anyway the problem ive been having is trying to get the colour by KCM working on a Grid fluid which I now know isn’t possible. It only works on the standard particles inside of realflow… Ah well, at least I know now hehe. Wanted to use that method on a very large scale scene.

:stuck_out_tongue:

#1229

Hi.

Anyway the problem ive been having is trying to get the colour by KCM working on a Grid fluid which I now know isn’t possible. It only works on the standard particles inside of realflow… Ah well, at least I know now hehe. Wanted to use that method on a very large scale scene.

you can use KCM color by vorticity technique on grid fluids also. Before simulating the core fluid open the export central and under the grid emitter options check mark Particle Cache (.bin) option this way when you simulate the core fluid a bin file is created for each frame, Once you have finished simulating load the bin files into realflow using a binary or Nbinary loader then click on the compute vorticity script button on the toolbar this will generate a new bin sequence which will contain the needed vorticity information. Coincidently i was just testing this out today and it works fine (drained my entire harddisk though!!). My Current render does not look so great i guess its because of low grid resolution (even with 94K particles with grid size of 356x119x119 and cell size of .085(m)!!!). I am getting this anoying shade grey color in my particles when i render them using kcm color by vorticity (same with gama corrected image, maybe its because of the lighting ?)… i have up’ed the KCM and Max setup images here:

another thing i am wondering… is it possible to make particles refract light in krakatoa?

thanks for help.

#1230

–Double post :shrug:

#1231

Not at this point. The way both the particle and voxels process particles does not allow for raytracing the resulting volumes. This is a bit like the difference between a scanline renderer and a true raytracer - the former has to keep a small portion of the data in memory, while the latter has to keep the whole scene at once to be able to shoot a ray through it. As result, the Krakatoa Voxel mode uses orders of magnitude less memory than the Max Atmospherics (as demonstrated by the numbers we posted comparing the FumeFX rendering of the G.I.Joe missile trail that required 64GB of RAM in Scanline but only around 600MB in Krakatoa). If we would create all voxel data in memory at once, it would be possible to calculate rays through the volume, but the drawbacks would outweigh the benefits, so I am not sure it will ever happen.
But who knows what the future holds… :wink:

#1232

The word of the day is Thinkbox :slight_smile:

#1233

…And the word for next month is Frost :slight_smile:

#1234

Is Frost the codename for a industry-leading geometry and particle mesher to replace blobmesh?

#1235

Excited! :smiley:

#1236

For anybody who missed it:

http://www.thinkboxsoftware.com/about/

This is the most exciting thing I’ve heard in a long time! :bounce:

#1237

Is Frost the codename for a industry-leading geometry and particle mesher to replace blobmesh?

Nah, do you not know how cold it gets in Canada during the winter season?!! Its probably more ICE than Frost’y we will see next month…

#1238

This is a good hint i think :smiley:

#1239

Hey there quick question to Furball89 (or anyone that have an idea), I’m trying to compute vorticity after simulating with a grid based fluid. The thing is that I don’t get any vorticity infos after the process…
(imported my grid particles with a binary loader then launching the “compute vorticity script”, I tried with the “compute vorticity” option turned on and off but still the same).

Any ideas ?

Sorry for the more RF than krakatoa question ^^

Velocity channel :

Vorticity channel :

Thanks !

#1240

(imported my grid particles with a binary loader then launching the “compute vorticity script”, I tried with the “compute vorticity” option turned on and off but still the same).

when you click on the compute vorticity button it will generate a bin sequence you need to load that bin sequence then you can see the vorticity. the vorticity script button will not overwrite the existing bin file’s vorticity channel, instead create new bin files with the vorticity channel.