RealFlow | Cinema 4D's "Image" emitter lets you use bitmaps and Cinema 4D shaders as emission mask to control the areas where particles will be created. The emitter's usage is straight forward:
Create a standard Cinema 4D material and load a texture map, a gradient, noise, or surface shader to one of the channels, e.g. "Color".
Alternatively, add a shader, for example "Noise".
Add an "Image" emitter.
Drag the texture thumbnail from the material to the "Bitmap" slot of the emitter – the texture will be shown in the viewport.
Scale the emitter and simulate.
If the simulation is slow you should consider decreasing "Texture Sampling Resolution" in the → "Preferences".
Particles will be created in all areas of the bitmap/shader; only purely black areas remain empty. Greyscales are treated like purely white pixels (= full emission). RealFlow | Cinema 4D only evaluates the red channel of a texture. |
The "Object" emitter also provides a "Bitmap" field, and the workflow to attach the image is the same as above. Anyway, there are a few things to know:
This emitter creates particles from the surface of an object.
In order to control surface emission through a map, the object has to be made editable and requires an "UVW" tag.
RealFlow | Cinema 4D can only take the UVWs it gets from the tag.
If there are just a few or no particles at all we recommend increasing the fluid container's → "Resolution" parameter, because it defines a particle's radius. If a polygon is smaller than a particle emission is not possible.
