Read Primivol review in Carrara 3D Expo issue number 5.
Primivol is a set of 4 volumetric primitives for Carrara. It contains a Fire primitive, a Cloud one, a Smog and a Rising Smoke. But these 4 primitives are in fact some build in presets of a far more generalist volumetric renderer. Primivol can render any 3D shader as a volumetric primitive, and can alter their shape with a set of modifiers and ramp-off functions. Lighting, self-shadow, density, color and many other parameters are accessible through the interface and can be precisely adjusted and animated.
An evaluation version is available. In evaluation mode, a red and a green sphere will be renderered in 2 corners of the primitives, and the primitives will only render a limited number of pixels, until Carrara is restarted.
All the documentation is available through the tooltips, but this page will give a brief overview of Primivol user interface.
All Primivol primitives share the same rendering engine and therefore share similar settings through a common user interface. This common interface is divided in 3 panels and then completed at the top by settings specific to the primitive’s type.
1 The General Panel
This panel is used to set the quality, the 3D shape, the self shadow and the modifiers on the volume.
The Quality setting and the self shadow setting influence directly the rendering speed.
The self shadows are pre-computed so when a volume with self shadows is rendered, some time will elapsed before the first pixel is rendered. The remaining rendering will be as fast as a regular rendering. Note that only distant lights (sun and moon light included) have an effect on the self shadows.
To get projected shadows, the light must use raytraced shadows. Shadow Buffer works only with faceted primitives.
The 3D shape of the volume is set with one of the 4 build-in noises, or with any 3D shaders of the scene. So for example all the Velouté noises can be rendered as volumes.
The deformers work like Carrara ones, and can be stacked one over another. Primivol contains 9 deformers: Bulge, Noise, Punch, Scale, Shift, Stretch, Taper, Twist and Wave.
2 The Ramp Off Panel
This panel controls the way the density of the volumetric primitive decreases with distance. 6 presets are available, but custom preset can be build using the 16 ramp off functions in the right part of the panel.
3 The Color Panel
By default, the color is chosen in a color gradient determined by the local density. But the color can also be set using ramp off functions (there are 6 presets available) or with any 3D shader of the scene.
4 The custom panels
Each primitive has its own panel with customs settings.
Here are the 4 basics primitives rendered with their default settings: Fog, Rising Smoke, Cloud and Fire.
5 Render through mesh
Primivol can also renders volumetric primitives using any mesh from the scene to delimit its shape. The short movie here shows an animated fire primitive using a text primitive to determine its shape.
Here’s another render of the same primitive in a less compressed file format. The volumetric primitive and the text primitive used to shape it are render side by side.
To choose the mesh from the ones available in the scene, there’s a new popup menu in the Ramp Off panel of the primitive. The Smoothing slider beside gives some control on the drop of density when the gas is near the sides of the mesh.
The mesh shape can be combined with the other ramp off options. To see only the mesh shape, all the other ramp off options must be unchecked (the 1st preset does it).
6 Sample Primitives
A few Primivol samples are available from the download page.