This might be quite simple.
Krakatoa v1.5.x does NOT render particles if they are not illuminated in some way anymore.
In previous versions, one would just set the Color channel and if there were no lights, the color would be used as Self-Illumination and the particles would be visible. In 1.5.0 and higher though, we introduced an Emission channel which is solely responsible for Self-Illumination. If you have no lights and no Emission, RGB will be black. If you want to see the particles, set the Emission channel of the particles to their Color channel and they will render.
There are several ways to do this depending on what you are using.
Method 1:
*Open the Krakatoa GUI
*Expand "Global Render Values" rollout.
*Check both "Override Emission" and "Use" buttons.
*In the Map slot to the right of the buttons, add a Vertex Color map.
*Since the default Vertex Color map renders the Vertex Color (Map 0) channel which is equivalent to the particles Color channel in Krakatoa, you now have your particles self-illuminated using the same color they would render if they were lit by a light.
Method 2:
*Open the Krakatoa GUI
*Expand "Global Render Values" rollout.
*Press the "Create New Global Channels Override Set"
*In the MagmaFlow editor, change the Output node from "Color" to "Emission"
*Make sure >AUTO is checked or press UPDATE to commit the changes.
*Enable ">Use Emission" in the Main Controls or the ">Use" button in the Global Render Values like above.
*If you render now, the color channel will be copied into the Emission channel and will be used to render the particles as self-illuminated.
Method 3:
*If you intend to render additively, the ">Force Additive Mode" option copies the Color channel into the Emission channel automatically, while setting both Color and Absorption to black, thus producing additive rendering.
There are also local approaches when loading PRT files using PRT Loader since you can add KCM modifiers to copy the Color to the Emission channel on a per-object basis.
Why so many approaches? One word - flexibility. Since we have added full support for Emission and Absorption to 1.5.x, we had to make sure it is you who decides how and when these channels are used.
Btw, the MagmaFlow Method 2 is faster than using a Vertex Color map since it does not involve rendering maps. I rendered 12M particles generated from a GeoSphere via PRT Volume in:
29 seconds with Emission channel off (black)
33 seconds with Emission channel on and no overrides (black)
33 seconds with Emission channel on and Global Channels Override (self-illuminated)
41 seconds with Emission channel on and Vertex Color Map Override (self-illuminated)
The general speed of KCMs is typically 10M particles per second, but the simple copying of one channel into another does not really cause a performance hit, so I would suggest using the Method 2.
As for rendering voxels, the colors of all particles falling into a single voxel will be combined to determine the voxel's color. If you have approx. one particle per voxel (either very few particles in a grid or very small voxels), the result will be similar to particle rendering, but the resolution of the rendering will depend on the world units size of the voxels.
Also note that you can render without a watermark at resolutions below 480x360 which is good for quick tests and YouTube uploads.
Forgot to mention - the Studio Monthly approach works in 3ds Max 2009 with Creative Extension and in 3ds Max 2010 since a bug in the Color channel loading in PFlow was fixed. Thus, it is now possible to project colors using a simple 3ds Max Per Pixel Camera Map, then bake these colors into a new set of static PRTs and then load these PRTs back into PFlow for animating.
Last but not least, one could use MagmaFlow to produce Camera Projections, too, but this is more to show off the power of the system and is not that user friendly:
http://software.primefocusworld.com... ction_Mapping
If this does not solve your problem, please let me know.
