3D Computer Generated Images 

3D Computer Generated Images


 Welcome to my virtual studio! Not only does creating art on a computer have the benefit of no muss, no fuss cleanup, but it allows almost whimsical experimentation. If the result is not desirable, just hit the UNDO button or revert to the last saved version of the masterpiece. All of this comes after mastering the basics of the chosen computer program. 

Hardware

 I use 3D Studio® 4.0 on a Pentium platform with 128 MB RAM and 1,2,and 4 gig hard drives. Ideally, one should have as much RAM as possible. 128 MB is more than adequate, but it still requires some special tricks if the 3D scene gets complicated. This is especially true when using automatic reflections, multiple objects and material bitmaps. Occasionally I will resort to rendering some of the objects separately then compositing them in Photoshop® 4.0. A flatbed scanner is useful for importing material textures to be used as surface maps in the materials editor.

Output printing

Of course, there is always the question of how to transfer large files to print. I formerly used Syquest® removable drives, due to their ability to port between platforms like the PC and Mac. It's a lot easier now, but when I first started doing it, I thought I was trying to teach an elephant to dance. Later I experimented with the Iomega Jaz® drive, which I occasionally still use. Now I much prefer writing a CD Rom, however tedious, especially if I am sending the file to a distant service bureau. Somehow, I feel there is less risk of the media getting lost in the mail. My first prints were made on an IRIS® printer using actual watercolor paper.  The quality varies depending on the bureau. The IRIS® printer uses vegetable dye inks which are not entirely stable, depending on how they are treated after printing. Some people still trust clear spray. I have had prints for two years with minimal fading, but they have this reputation. A lot depends on ambient light level, just as with oil paintings.

Depending on the desired look, a photographic quality image can be easily produced using the Nikon® slide/print film recorder. This image is then photographically enlarged in the usual way any 35mm photographic image is enlarged. For ultra demanding requirements larger film recorders are available. I send all these out to a service bureau three blocks from my house.

None of this is required if the image is to be viewed only on a computer monitor. With 3D Studio® it is possible to output broadcast video animation with additional hardware. And the number of add-on software accessories for simulating physical world properties (such as impact detection and gravity) are plentiful.

Goals of this tour:

  • Convey the conceptual difference between 3D and 2D computer graphics
  • Demonstrate some simple 3D modeling techniques
  • Hint at the material creation process
  • Emphasize the importance of lighting
  • Spark some creative ideas of what may be possible with this medium

What do you mean it's 3D?

3D computer generated images, as compared to the stereo-dot type images faddish a while back, are actually 2D images created with 3D modeling techniques. No special apparatus or cross-eyes necessary. Think of creating a sculpture and then photographing it from whatever angle looks best. But the sculpture and camera only exist in the computer's imagination.

The analogy breaks down a little with regard to sequence. A sculptor will usually choose his material first, then shape it into a work of art. The computer allows creation of the shape first, without regard for materials, which are assigned later at leisure. This might prove handy if your wealthy patron cannot decide between white marble or bronze!

I use an IBM compatible computer running Autodesk 3D Studio® release 4. This is a polygon based modelling, rendering, and animation program consisting of 5 modules:

  1. The 2D Shaper - to draw shapes and "paths".
  2. The Lofter - to convert 2D shapes into 3D objects by extruding them along a "path".
  3. The 3D Editor - to create and modify 3D objects on an object, element, or vertex level.
  4. The Keyframer - to animate and also for special modelling tricks.
  5. The Materials Editor - to create the materials for objects.

But enough of the talk, let's look out how I put together a rather straightforward image:

 

walls64.jpg image 

Creating the Space
Since the end result must be 2 dimensional, I wanted to convey a sense of space and depth, so I created these 4 rectangles to serve as walls. Later they would be assigned a blue water "material" and given a reflective surface. These watery walls will enclose the entire work. 

loftsp64.jpg image 

Lofting the Helix
Many things can be automated by 3D Studio®, one of these is the creation of a helix. Here you see the dialog box asking for parameters including the beginning (100) and ending (10) diameters of the helix "path", as well as the number of turns (1.5) [highlighted].

 The path itself would be invisible if I did not assign it a "shape" (its cross-section). In this particular case, I assigned the same shape (white squiggle) to each end of the path, but scaled one of the shapes (the yellow squiggle) down to almost nothing so the helix tapers to a fine point at one end. 

 

helic64.jpg image 

Mating the Mesh
The 3D "object" created is called a "mesh", it probably reminded someone of chicken wire. Anyway, I wanted two interlocking helix meshes.

 This was accomplished by a making a copy of the original helix and mirroring it, so that I ended up with two helixes identical in every way but their orientation. In this picture the original object is red, and the mirrored clone is white. 

Rendering of the unfinished image 

Sneaking a peek
By this time, I really wanted to know if I was on the right track, so I rendered a sneak preview. As you can see, I hid all but two walls in this view, and the material assigned to the blue helix is completely different from that in the final image. 

bevlto64.jpg image 

That extra touch
One problem with computer generated images is that they sometimes look "too perfect". Edges are too sharp, surfaces too smooth. One way around this is to blunt the edges of sharp objects.

 I created this "bevel tool" which is simply a shoe box shaped object rotated at 45 degrees and aligned with one sharp edge at a time. Using the CREATE/BOOLEAN/subtraction command I was able to shave off the sharp edges and add a touch of realism. 

bendse64.jpg image 

Didn't make the Cut
Since it is impossible to reach inside and move or bend things by hand, computers rely heavily on things like "selection sets" (red).

 Here, by selecting the upper vertices of both helices, and using the MODIFY/OBJECT/BEND command, the top is pushed to the left. 

I didn't like it. 

key64.jpg image 

Key of Life
I photographed the ankh, or key of life, on an Egyptian ruin wall. The Kodak PhotoCD® process converted it into a digital file, which was converted to KEYLIFE.TGA, a file format readable by 3D Studio®.

 This image was also blurred in Adobe Photoshop® to create the sandstone material for 4 rectangles and one helix. 

keylif64.jpg image 

The fun begins
We are now in the Materials Editor, one of the most important tools in simulating realism. As you can see there are more options here than buttons on your VCR remote, so I can't go into all the details.

Notice the ankh in the upper left hand corner. This is a "material" that I am preparing for one of the objects in the final scene. Since this is a rough stone material, I have assigned it a very low shininess strength, as represented by the gentle bell curve. 

KEYLIFE.TGA is a bit map assigned not only as a "texture" (arrow, regular bit map) but also as a "bump map" which creates illusion of raised and lowered surfaces based on the luminosity of the source image (KEYLIFE.TGA). 

nearen64.jpg image 

Lights and Camera
It is possible to render a scene without a camera, but without light the image will come out black every time. Here you see multiple lights (yellow stars) projecting yellow cones representing that light's falloff.

 Radiosity (the faint glow of color cast by objects on nearby objects) can be simulated by using colored lights. For example, I used a green light to shine on portions of the other helix where it was closest to the green helix. You can't see it here, but trust me on this one. Check out the final image for the end effect. It is not obvious if you are not looking for it, but it looks "wrong" if it isn't there. 

 

final.jpg image 

The End
Well, not really. Somehow the image has to be rendered at high resolution and converted to a digital print. The first time I rendered this image at full size it took nearly 6 hours to create the 35 megabyte image file. I have a faster computer now with more RAM. You probably know how that goes.

 I hope you enjoyed this mini tour of my studio. Come back soon.  If you want to buy or commission a work, just email me at



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Last modified 2004 Sept 2.