Greenworks Xfrog 3.5/4.x review
Xfrog from Greenworks is widely recognised as the top-of-the-range procedural organic 3D modeller. Specialising in producing absolutely realistic vegetation, the name is an acronym for X-windows-based Finite Recursive Object Generator. Xfrog grew out of academic research into natural organic structures, which recognised that apparently complex plants and trees are actually built on just a few relatively simple building blocks – the key is how these objects are repeated and distributed.
Xfrog provides dedicated components for creating, distributing and affecting geometry, such as the Tree component for handling branching, the Phiball component for multiplying elements across the surface of a sphere (think sunflower head), and the Attractor component for deforming geometry. Put the nine attractor components together with a limited range of primitives, such as Tubes and Triangles, and you can quickly generate the framework for a complex plant or tree simply by dragging and dropping from Xfrog’s Library panel onto the Hierarchy Editor.
With the geometric framework in place, your plant can be fine-tuned to bring it to life using the tabbed Parameter Editor that runs down the right of the screen. Using the Materials tab, you control surface appearance, say, loading a realistic bitmap of a leaf complete with alpha transparency onto the basic triangle primitive. And by using the dedicated tabs for each component in your hierarchy, you then take absolute control of the plant’s shape. With the Wreath component, for example, you set the number of repeated objects and their radius while with the Tree component you can specify whether branches should be arranged perpendicularly, laterally, in pairs and so on.
The central Tree component’s parameter tab also provides a whole host of advanced functions for controlling aspects that vary over distance, such as trunk size, growth scale and density, which are handled via simple onscreen graphs. These functional parameters are great for producing variations on a theme, and are particularly important as they can be keyframed to produce animations. Since Xfrog is based on the way that real plants grow, you can quickly create a realistic animation of your plant developing over time, putting out new shoots, growing towards the light and so on.
So what do you do with the finished model or animation? As Xfrog can handle only one plant at a time, and doesn’t offer rendering itself, you need to work hand-in-hand with another 3D modeller. Models and sequences can be output to various formats (including OBJ, LWO and 3DS), complete with texture maps, so you’ll be able to load your Xfrog plants and animations into just about any package. However, with advanced plants consisting of thousands of objects, this can be unwieldy to say the least. This is why Greenworks provides dedicated plug-ins for a number of packages, such as 3ds max, LightWave, Maya and Cinema 4D, that enable XFR files to be imported directly.
This is a big step forward, but you immediately lose the full control that Xfrog itself offers. If you’re effectively just importing a mesh, then consider alternative methods, not least buying in a third-party model. The ideal would be to have Xfrog’s organic modelling power actually there within your favourite 3D application. Greenworks clearly thought the same, which is why its latest Xfrog 4.x technology no longer operates standalone but rather as a plug-in from within either Maya or Cinema 4D.
We looked at the version of Xfrog 4.2 that works with Cinema 4D 8.1 and higher. Cinema 4D makes a natural host, as the hierarchical Xfrog components can simply be converted to hierarchical Cinema 4D objects. In the porting process, Greenworks has taken the opportunity to rationalise, combining the former Tree, Horn and Leaf components into a single, more powerful Branch object and merging the Hydra and Wreath. It has also added new power, with a Variations object for alternating multiple repeated objects, a dedicated Curvature object for parametrically defining and animating splines, and support for Pruning objects.