Hello,
pls how to set Opacity PP to krakatoa PRT loader particles?
Thank you, Tomas
There are a few ways to assign density.
If you are using Maya’s particle or nParticle systems:
-You will need to assign values to the per-particle “opacity” attribute (“opacityPP”) of the particle system.
-These opacity values will be interpreted by Krakatoa as “Density”.
If you are using a PRT File:
-The PRT file will need to have an existing “Density” channel to have per-particle densities.
If you want to manually set the Density for a set of particles:
-Open the “Krakatoa Modifiers Editor” dialog window.
-Add a “Set Float Channel” to your object.
-Then in the “Extra Attributes” section of your emitter or PRT Loader, you can assign a value to the “Density” channel.
If you want to globally override all Density values:
-Open the Krakatoa Renderer Dialog
-Under “Global Render Values”, modify the Density override.
Let me know if that works for you.
Thank you very much for answer. Sorry, I was not unfortunately so exact in my question. Example. I have PRT cache with particles with different AgePP (lifespanPP in Maya) I need to map opacity ramp by age of particles, so at the beginning will be not transparent, at the end fully transparent. Is there exists any channel such Age?
Thank you, Tomas
edit:
…I created simple sim in Realflow, imported bins to Maya as Prt loader and Copy Channel From: Age To: Color…
and I can see particles are good! At the beginning black, at the end of life white. So there is something like Age channel. But I dont know, how to map Age to Density, it doesnt work for me.
Thank you for patience, Tomas
If your .BIN files have an “Age” channel, you should be able to use that in Krakatoa. In Krakatoa for 3ds max, you could use Krakatoa’s Magma modifier to assign density to be a function of age. However, we don’t have Magma in Krakatoa Maya yet.
There may be some tricks you can do to get something working though. You could try:
- Creating a “Copy” modifier on the PRT Loader. Set the source to “Age”, Set the destination to “Density”. This will put your age data in density channel, and allow Krakatoa to access it.
- Add a “Scale” modifier and set the channel to “Density”. This will allow you to scale the age values to something that might work.
UPDATE EDIT: I am working to get a solution that can help you achieve this goal.
Allright, I will try it, otherwise I looking forward Magma…
Tomas.
edit:
Oh, it is easier than i thought. Instead of using PRT loader, I use normal Realflow Bin Loader, and than I can use all PP attributes as with normal particle Shape.
Oh last thing. Maybe I miss something, but could be density value of particle something else than 0 or 1? B
Finally I see, that density PP works only for Voxels rendering method not for points. Point can be only 0 or 1.
A word of warning - RealFlow BIN files contain a Density channel. This Density channel has NOTHING in common with the OpacityPP / Krakatoa Density channel used for rendering point or voxels. Very often, the BIN file’s Density can be 0 and the particles won’t even render in Krakatoa.
In Krakatoa, the Density value describes the contribution of the particle to the spatial density of the particle cloud. Please make sure you read this topic: thinkboxsoftware.com/kmy-vol … rendering/
The Krakatoa Density can be a floating point value and does not have to be 0 or 1. It could even be negative, although it is not recommended, because the behavior of light wouldn’t be physically correct. But I have used it for visual effects…
The Density channel in RealFlow has a different meaning related to the physical properties of the fluid. I don’t know what its value range is.
Hello Bobo,
thank you for link. Unfortunately something is still wrong with my opacityPP…Look at attached pic. There are couple of renders (Maya Hardware, Krakatoa and Fury) It is simple scene with volume emittor and in particles is opacityPP ramp as you can see. What could be problem here please?
Thank you, Tomas.
Picture here: imagebin.org/248599http://imagebin.org/248599
PRT Loaders will be able to load all the channels from a BIN file.
Krakatoa understands a few different channel names. They are:
Position, Color, Density, Velocity, Absorption, Emission, Normal, Tangent
PRT Loaders will load the following channels from BIN files:
Position, Velocity, Force, Vorticity, Normal, Age, ID, NeighborCount, TextureCoord, RealflowInfoBits, IsolationTime, Viscosity, Pressure, Mass, Temperature, Density
(As noted by Bobo: The “Density” channel from a realflow BIN is not related to visual density, so it should be overwritten if it exists)
You can set, scale, and map any of the source channels to destination channels using modifiers. We would like you to use the PRT Loader, but if it is not working for you, how can we improve it?