Tom Arah goes in search of ways of bridging the 2D-3D divide.
Realistic 3D handling takes your 2D drawings into new creative
A few months ago I looked at the importance of 3D handling to
realistic illustration and the ways in which the major 2D drawing apps
have begun to embrace the fact. There’s still a huge way to go
however, so is there an alternative way of bringing your vector drawings
to realistic life?
The ideal would be to simply extend your existing 2D skills into the
third dimension and there’s one program that promises to do just
that – SketchUp 3 from @Last Software ($475). In many ways SketchUp
operates like a traditional 2D vector application with its Drawing toolbar
providing the basics of rectangles, ellipses, curves, polygons and lines.
As you draw, coloured dots and coloured lines keep appearing to help
you align your work to the existing geometry by snapping to existing
edges, midpoints, tangents and so on. Once you’ve drawn your objects
you can select and group them and reposition, scale and rotate them with
the tools on the Edit toolbar. This also provides the Paint tool with
which you can apply flat colours and tiling bitmap textures.
So far so ordinary. Where SketchUp moves into entirely new territory
is with its Views toolbar. Here it becomes apparent that so far we’ve
been working in Top view looking down on our artwork from above. If we
switch to the Front, Back, Left and Right views there’s not much
to see as of course our artwork is completely flat. If we switch to ISO
view, however we get an isometric projection which by default shows a
perspectivized view just as it would look to a human observer looking
at the artwork laid out flat on the ground. And using the tools on the
Camera toolbar, in particular the Orbit tool, you can interactively and
instantly set up this perspective view exactly as you want it.
This is a big step forward compared to trying to manage perspective
in a traditional drawing program, but so far all our objects are still
resolutely two-dimensional. But this is where SketchUp works its magic.
Using the Push-Pull tool in the Iso view you can simply select your shapes
and drag them upwards to extrude them, instantly turning a rectangle
into a cube for example. Even more powerfully you can use the other Edit
tools with these new 3D objects. By scaling the top surface of the cube
down towards a point for example you can create a pyramid, while moving
the surface creates an angled effect. When you get to grips with just
what’s possible – offsetting surfaces, rotating planes and
edges in 3D space and so on – you can create advanced 3D shapes
Even more impressive is SketchUp’s ability to interactively draw
3D shapes from scratch. This is possible thanks to its underlying “inference” engine.
We saw this at work in the constantly appearing coloured snap lines when
drawing in 2D and SketchUp’s stroke of genius is to simply extend
the same idea by looking for connections to the existing 3D geometry
and the main drawing axes. It takes a bit of getting used to, but eventually
it becomes second nature. Adding a roof to our extruded rectangle, and
then a dormer window for example takes just a few lines and a few seconds.
SketchUp seamlessly moves vector drawing into
the third dimension.
Being able to literally “sketch up” a 3D model like this
is creatively exciting, but so far we’ve only been talking about
straight lines and flat surfaces and of course the real world is much
more complex than that. So what do you do if you want to add a curved
object such as a cylinder or cone? It doesn’t look like it’s
a problem – simply add a circle and then use the Push-Pull tool
to turn it into column and the Scale tool to turn it into a cone.
It’s important to realize though that, behind the scenes, SketchUp
is using a workaround - breaking the circle down into short line segments
that it then stretches into co-planar surfaces. Thanks to the program’s
in-built and customizable smoothing when it comes to onscreen display,
the cylinder and cone look curved but, if you turn on the display of
hidden geometry, you’ll see how the effect is actually produced
with flat planes. Generally the workaround works well - after all you
can always break down any shape into a series of smaller triangles which
by definition are co-planar. However it would be almost impossible to
draw an advanced curved shape like a sphere from scratch – instead
SketchUp provides these as comparatively crude ready-drawn components
- and you can forget about creating realistic organic 3D objects such
as a human face or figure.
SketchUp certainly isn’t a replacement for a traditional 3D modeling
package (its main target market is architects), but it’s still
surprising how realistic the scenes it produces can be. This is firstly
thanks to SketchUp’s use of bitmap fills which means that walls
really look like solid brick and lawns like growing grass. It’s
the speed with which these perspectivized bitmaps are handled which is
extraordinary enabling you to move the camera viewpoint through your
model while its rendering is updated in real-time. Just as impressive
is SketchUp’s handling of shadows. You set these for the scene
as a whole by setting the location and time of year and day and SketchUp
creates accurate shadows based on the position of the sun. These shadows
are geometric projections rather than softened bitmap effects but they
still go a long way to bringing the drawn model to life.
SketchUp’s combination of 2D drawing and 3D modeling certainly
helps produce eye-catching illustrations within the program but it’s
also important to be able to use these drawings as part of larger workflows.
SketchUp’s central crossover role here is especially apparent with
its ability to output its vector illustrations to multiple formats. The
simplest option is to output your drawing as a bitmap such as JPEG or
TIFF (you can even output camera-based animations to AVI format). Much
more impressive is the fact that you can output your scenes as 3DS models
complete with texture maps ready for import into a traditional 3D modeling
Here we’re more interested in maintaining the scalable, resolution-independent
vector nature of SketchUp’s 3D illustrations. For further work
in a CAD program SketchUp supports output to the technical DXF and DWG
formats, but what we’re looking for is further creative handling
in the mainstream drawing apps. Again SketchUp promises to deliver with
its ability to export to the EPS and PDF formats which Illustrator, CorelDRAW
and FreeHand can then import. Working like this, it looks as if SketchUp
should make a natural partner for originating 3D elements to help make
our 2D illustrations really stand out.
That’s true to an extent but in practice the major elements that
brought the SketchUp model to life – bitmap textures, realistic
projected shadows and onscreen smoothing - are largely lost in the conversion
to EPS/PDF. With a textured and shaded sphere, for example, the bitmap
texture is converted to a single appropriate flat colour and the on-face
shading information is then used to darken this colour appropriately
on each of the clearly visible planes that make up the faceted pseudo-sphere
(for some reason the ground shadows are lost completely). It certainly
gives the impression of 3D but in a less than realistic and undesirably
SketchUp’s vector pdf/eps output
It’s a big step towards the goal of adding realistic 3D handling
to the main 2D illustration apps but there’s no hiding the sense
of disappointment. So is there another way? The ideal would be a dedicated
3D modeler that allows its images to be exported to a standard vector
format. That way we would break free from SketchUp’s strong bias
towards clearly faceted drawings and be able to produce much more sophisticated
and organic 3D objects. The problem is that the dedicated 3D modeling
applications have a different agenda. Rather than outputting scalable
drawing-style vectors they are working with advanced procedural materials
and texture maps to produce the most photo-realistic ray-traced bitmap
renderings that they can.
It looks like a dead-end, but then I remembered Electric Rain’s
Swift 3D ($169). This is a 3D modeling program with a difference as the
whole application is tailored towards producing Flash-based SWF animations.
Flash is a vector format so sure enough, while it doesn’t exactly
advertise the fact, Swift 3D also supports the export of single frames
to the EPS and Illustrator AI vector formats which is just what we are
Considering its price, Swift 3D provides some surprisingly powerful
3D modeling capabilities, beginning with a range of pre-provided primitives,
such as planes and spheres (unlike SketchUp you can control the number
of polygons that make up the sphere and so its smoothness). You can also
create your own 3D objects using the dedicated Extrusion Editor and Lathe
Editors. It’s simple for instance to import a flat logo from Illustrator
and then extrude and bevel the results to produce a three-dimensional
version. More powerful still is the ability to import 3DS models. Working
in this way it’s possible to bring in scenes from just about any
3D modeling application from SketchUp buildings right through to Poser
figures and even simplified Vue Pro landscapes.
What really makes Swift 3D different though is its dedicated “RAViX” vector
rendering engine. In fact the technology is so special that Electric
Rain has also developed it as dedicated rendering plug-ins for 3ds max
and Lightwave ($295) and licensed it to other developers such as Eovia
who market it as VectorStyle ($129) an add-on for Carrara. In each case
the core settings to choose from are the same. Firstly you need to control
the lines in your vector output by setting whether to outline anything,
just the object’s edges or the entire polygon mesh and, where relevant,
the level of internal detail that the RAViX engine should look for.
Electric Rain is the master of vector rendering.
It’s the handling of fills though that is the real key to RAViX’s
vector rendering capabilities and success. The first option on offer,
Cartoon Single Colour, is the simplest as it renders each object as a
single colour so that a test sphere outputs as a simple flat circle.
That’s hardly convincing but you can improve the perceived 3D appearance
by switching on Shadows, Reflections and Specular Highlights (small gleams
which indicate the shininess of the material), all of which immediately
bring an otherwise flat fill to 3-dimensional life.
The real key to adding realism though is to increase the number of colours
generated for each object with the Cartoon Two Colour, Four Colour and
Average Colour options. In each case the RAViX engine breaks down the
model into groups of polygons that are similarly angled to the light
sources and so can have the same colour applied to them. The biggest
leap comes with the last Cartoon option, Full Colour, where each polygon
(up to 200,000 in total!) is individually coloured. And the RAViX engine
takes things even further with its Mesh Gradient fill option where every
polygon is filled with a linear gradient. The results can be astounding.
I loaded a dinosaur 3DS exported from Poser into Swift 3D, for example,
and applied one of the program’s procedural textures and the resulting
fully scalable vector gradient mesh was almost indistinguishable from
a bitmapped render.
Now all we need to do is to import the gradient mesh into a 2D drawing
application and we have the best of all possible worlds – a fully
scalable, near photo-realistic 3D model that is ready to be further processed
in your drawing package of choice. But there’s a problem. The gradient
mesh option is only available when outputting to Flash SWF format (I’m
not sure why as linear gradients are PostScript-compatible) and neither
Illustrator nor CorelDRAW support SWF import. FreeHand does however,
so it’s possible to load the 3D gradient vector image and very
striking it is too - no matter how large you scale it. Unfortunately
the SWF is embedded as a movie and so can’t be broken apart for
further processing. And, when you output it, the anti-aliasing that makes
it look so good onscreen makes it look undesirably soft in print. For
the moment then it’s back to the Cartoon Full Colour option for
the most realistic PostScript-friendly rendering and to the other Cartoon
options for a more hand-drawn appearance and easier handling.
Vector rendering involves a trade-off between
quality and editability.
It’s another disappointment but it’s important to recognize
how far we’ve come. With SketchUp it’s possible to take existing
2D drawing skills into the third dimension, successfully straddling the
worlds of 3D modeling, CAD and creative drawing. And with Electric Rain’s
Swift 3D and RAViX rendering engine, it’s possible to get your
favourite 3D modeler working hand in hand with your favourite drawing
package to give your illustrations real depth - and a creative edge.
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