Cheetah 3.4 Review

Cheetah 3.4 Review
by Tim Danaher - http://vizarch.blogspot.com

Tim is an architectural visualizer, specializing in SketchUp and rendering with Cheetah3D, modo 202, amongst other. He can be contacted at timdanaher@gmail.com

Here we'll be looking at Cheetah3D version 3.4. Cheetah (or C3D) is a Mac-only modeling rendering and animation program that has found great favor with architects due to its streamlined interface, great rendering options – and its extremely low price. Version 3.4 may seem like an odd version number to choose for a feature review – we were considering waiting for version 3.5 (as is the standard practice), but we've been assured by the program's developer, Martin Wengenmayer, that 3.5 will be concentrating on areas not of immediate concern to architects (most notably the addition of skeletal rigging systems for character animation).

First off: interface. Previous users will notice that in Version 3.x the Materials browser has been moved from a slide-out tray to its own pane within the interface. The Material icons have also increased in size. These two changes make the Materials interface much easier to use – all we need now is 'Tool Tip' pop-ups for material names, since these are by necessity truncated. Materials can now also be dragged-and-dropped directly onto objects in the Editor window and there's a Spotlight search (Mac OS X's instant search facility) built in for large material collections, although some form of organizing materials into tabbed libraries would be really welcome.

While the interface does lack polish in some areas (name fields could be a little more accommodating, for instance), it is extremely malleable and can be set up for the task in hand. There are Modeling and Animation layouts as standard, and now there's also a new layout: UV Editing. This was one of the big changes in version 3.0. UV mapping is a way of seamlessly mapping textures onto irregular surfaces: in other words, where the standard cylindrical, cubic, spherical and planar mappings won't suffice. Bringing up the UV Editing interface places the UV Editing window next to the main Editor window, and the mesh of any selected object will be displayed in UV space in this window. The first time you do this, the UV map will generally be a mess, full of overlapping polygons. The trick now is to define seams on your mesh that will allow it to unwrap cleanly. Once that's done, you can define color, bump and displacement maps in the appropriate channel of a material. It's then a matter of painting on your detail in the UV editor. At present, only information in the Color channel updates live in the editor. If you want to see the results of a bump or displacement map, a final render is in order. Cheetah also provides a new Brush tool for the painting, along with an Eraser, Eyedropper and a Paintbucket, and Straightline, Square and Circle tools. Various Brush profiles are provided, but as yet there's no provision to define your own. The Brush tool is, however, fully pressure sensitive and works well with graphics tablets.

Cheetah's modeler contains a very useful set of tools based on Spline and Polygon objects. These can be acted upon by Creator objects – Extrude, Lathe, etc., and Modifier objects, of which the most important is the Subdivision object for creating smooth-flowing objects from low-resolution polygon cages. This would be useful for the creation of, say, tensile structures in conjunction with other modeling packages (like SketchUp) where such tools are not provided as standard. Cheetah's modeler also contains a Symmetry modifier, allowing you to sculpt symmetrical objects using only half the number of modeling operations. These modifiers are applied as 'Tags' to the base objects in the Scene Browser as are many other modifiers – not just those for modeling. Parameters for any property can be accessed by clicking on its tag, and, of course, entire sets of properties can be easily removed by deleting the tag, although as yet there's no method for transferring properties between objects by alt-dragging tags to copy them. Version 3 also added some new modeling modifiers: Array, Ring (for radial arrays) and Transform. This latter allows the conversion between local coordinate systems and should prove useful in animations.

Cheetah also contains a fantastic set of rendering tools, and it's these tools that have largely endeared it to architects and designers. Radiosity and HDRI (High Dynamic Range Image) rendering are fully supported – a feature, which at this price is amazing, especially when you consider that in many programs (like Cinema4D and form•Z) these rendering features are only available as expensive add-ons to the main program. As with modeling, Radiosity and HDRI are applied via their respective tags to Camera objects – they're not applied at the scene level, meaning you can have multiple Radiosity / HDRI set-ups in a single scene file. On the Radiosity front, Cheetah offers true Radiosity, and also the much faster Ambient Occlusion method. This latter is not 'true' Radiosity, but it would be an eagle-eyed observer who could spot the difference. Also, the three-to-four times faster rendering for Ambient Occlusion more than offsets the miniscule degradation in fidelity. Cheetah's HDRI implementation can make use of both .hdr (Radiance) format images and the OpenEXF format, the High Dynamic Range format from Industrial Light & Magic.

Another thing that Cheetah does particularly well is render management – all rendering takes place in a separate window from the main Scene Editor window, and all completed renders are kept in a reviewable queue, which appears in a slide-out 'drawer' at the side of the Render window. The Rendering engine is written to be highly multi-threaded, meaning that you can render multiple views – and views from multiple documents – all at the same time. Also, renders are split across however many processors are on the host system. There's no distributed (network) rendering yet, but it's promised for a future release. All renders made in a single Cheetah session can be inspected, saved or deleted as required from this queue. It really is an object lesson in How To Do It Right. Of course, having a lot of renders in the queue can eat up memory and slow the program down, but the ability to quickly flick through several versions of a render – to check lighting, for instance – is invaluable. One thing that really is missing, however, is the ability to do a quick area-marquee render of a part of a scene. We know that this is coming, but Martin is unable to say exactly when. As well as standard views Version 3.0 has added the ability to render out Panoramas – these can then be processed in third-party programs (like Apple's MakeCubic.app) to produce 360-degree QTVR panoramas. There are also other new new Camera tags: Caustics and Depth-of-Field blurring. This latter is nicely implemented, with a blue grid giving visual feedback of where the effect will start in the OpenGL Editor window, although as with any program, DoF can increase render time significantly. The Caustic tag is good for creating focused reflections, like those than emanate from thick, irregular glass, or those scattered by by the surface of water in bright sunlight.

Having such neat rendering tricks at your disposal is all very well, but they don't amount to anything unless you can easily get your model into the program. While Cheetah has its native .jas file format, this isn't (yet) supported by any other applications, so the user needs to rely on the standard data exchange formats to move data in and out of Cheetah. Luckily, it does a good job with the most popular formats (.3dmf, .3ds, .dxf, .lwo, obj, .rib, .sia, .stl, .mtl .epx and .fbx). Of these, .3ds and .fbx will probably be the most used for 3D geometry, and of course the provision of .epx (EPIX format) means that Cheetah renders can be taken into Piranesi for final effects and entourage placement. Still, shuffling geometry between a modeling and a rendering application can be a chore – especially if you need to go back to your modeler and tweak some geometry. To this end, Cheetah has implemented a brilliant feature called a Smart Folder. This essentially acts as a conduit between a modeling application and Cheetah (it was actually implemented at the behest of the large number of SketchUp users who use Cheetah). Essentially you place an exported model inside a Smart Folder and apply materials to it and render. Now, if you need to change the geometry in the originating program, just re-export the model and the copy in Cheetah will update automatically – but keeping all your lovingly-created, Cheetah-defined material definitions intact. How it actually does this is by creating a link to the external exported file: no geometry is brought into the scene file itself. This means that the scene files are reduced in size to a few hundred kilobytes, and opening and saving them is much faster. There are a few glitches, though: while Material Definition tags are retained, Render tags (which control shadow casting, visibility and Radiosity participation) aren't, meaning that they have to be re-applied each time the model updates. A fix is promised for this soon.

As for animation, all objects and their materials are fully animatable, but for architectural work, probably the most useful feature is one of the most recent additions: Spline Tracking. Spline tracking is a property applied to a Camera as – you've guessed it – a tag. The tag's properties link a particular camera with a particular spline in a scene and cause the camera to follow the spline. It's that simple. You can choose to align the camera either tangentially or to individual segments or, by adding a Target tag to the same camera, the camera can be made to look at a certain point in the scene throughout the animation. Spline paths can also be drawn point-by-point, and the individual points and handles edited in a similar way to Photoshop / Illustrator Béziers, although it can be difficult to select Spline points if they've been moved into the volume of a model.

Probably the most intriguing aspect of version 3.0 was that it was an Intel-ready Universal Binary – it was one of the first Mac 3D programs, in fact, to be ported – beating the big boys by some margin – and second only to Cinema4D. The results of this port can be felt first in the interface: OpenGL view manipulation on heavy-geometry models is impressively smooth. What's particularly interesting, however, is the rendering speed results we've been seeing. Informal testing of a dual 2GHz PowerMac against a 2GHz Core Duo iMac, both with 2GB RAM, shows the latter machine posting rendering speeds an unbelievable two to three times faster on complex HDRI and radiosity renders. This may be due to the Core Duo's large 2MB L2 cache. Whatever the reason, it's impressive. Put the same scenes on a new Quad-core Mac Pro (we used a 2.0 GHz model with 4GB RAM) and the results are jaw-dropping: around two-to-three times the speed of the iMac and up to six times the speed of the PowerMac on HDRI-Radiosity renders. Impressive indeed. As is this new release of Cheetah. Your $99 will get you a lot of 3D technology – and free upgrades to all 3.x versions.

Product Name Cheetah 3D 3.4

Maker Martin Wengenmayer

Price $99

Requirements Mac OS X 10.4 + G3 processor + 256 MB Application RAM

Help web forum

URL www.cheetah3d.com

Captions / Screengrabs

Cheetah presents a clean, uncluttered, malleable interface. OpenGL speed is impressive, even on complex models like this

Render management is exemplary. The manager is holding seven completed renders, with seven concurrent renders running. Note the quad-processor division of the scene

Since version 3.0, Cheetah has allowed you to paint Colour, bump and displacement UV maps directly, but brush performance can lag a bit when things get complex

HDRI and radiosity rendering and Depth-of-field effects are included as standard, as can be seen in this image by Peter van der Elst

Subdivision algorithms are able to produce high-quality meshes. Note also high-quality, lit OpenGL meshes. Model courtesy of Peter van der Elst

The new Blueprint object in 3.4 aids in the peparation of geometry from standard plans, sections and elevations. Model courtesy of Peter van der Elst

The fast, high-quality HDRI and radiosity implementation – at an extremely low price – have endeared Cheetah3D to architectural visualizers and product designers alike. Image by author

As well as standard .hdr files, Cheetah 3.4 has also added support for the new OpenEXR High Dynamic-Range format, pioneered by LucasFilm studios and Industrial Light & Magic

 

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