RayTracker INFO page

• Introduction
• RayTracker "features"
• Some pretty pictures

I put every ounce of developement time (late nights and early mornings) into making it produce realistic images (I always felt everybody else implementing raytracers got stuck in the "I want to make it faster" trap. I completely ignored speed, and bet my resources on realism. And there are still some nifty stuff that RayTracker can do that almost nothing else can).

But I have now completely stopped developing it (since almost 20 years, I might add!), and have devoted my joy to other things and do my computer graphics somewhere else. So don't ask me for a copy - please.

• Light is added nonlinearily, to avoid burn-outs. [My innovation]
  Ever get annoyed at the thin line you must dance between everything being too dark or blown out? There are many reasons for this, one being your images are not linear, even if you *are* using Gamma accurately. One being, our eyes doesn't percieve light linearily. And so on.

  RayTracker got around such things by treating light magnitudes nonlinearily. 1 plus 1 did not equal 2 in the world of RayTracker light math. Basically, it was a kind of tone-mapping, but it was performed on the lighting level rather than on the final pixel. Of course, from a physics point of view that makes very little sense, but it made some rather nice images, because it played into the hands of our perception of light, rather than fighting it. A rainy day I will write a paper about the details - but suffice to say that it worked very well.

• Texture Displacement by bumpmap Some tricks was utilized to first calculate the bump vector, then displace the UV coordinates such that the texture space was perceived to be displaced along those bumps (i.e. a checkerboard on a bumpy plane didn't appear to have straight checkered edges, but wobbly).
  Also, bumpmapping took view angle into account a little bit to simulate occlusion of the bumps, giving emphasis to the sides of the bumps pointing "towards" the viewer and deemphasized the bumps pointing "away".

• Specify colors using CNS (Color Naming System)! Don't tweak gliders, really write "Very light yellowish-green"!

• Interrupt rendering at any time, to be resumed later... (when a long animated rendering can take a week, this is a nice feature) :-)

Things RayTracker did -91 that was ahead of it's time THEN (but is common NOW, 20 yrs later):

• Flexible 'map' technology. A major feature in RayTracker is the concept of a 'map'. A 'map' can be used in several ways:
  • Texture-mapping: Apply color to the surface from a 'map'
  • Bump-mapping: Apply surface variance over a surface (like wobbles, engravings e.t.c.) from a 'map¨
  • Reflection mapping: Fake reflections (much faster than real raytraced reflections) from a 'map'
  • Foreground and Background: Use any 'map' as foreground or background images. Backgrounds can be either linked to screen coordinates, or to "space" coordinates (a spherical map with infinite radius).

  At the time (early 90's) most rendering programs could do all the above, but most only apply one image at the time as a 'map'. RayTracker allowed any number of maps to be combined.

  • ...different scalefactors
  • ...different angles
  • ...different coordinate systems (wrapped to surface UV coordinates, or "projected" on the XY, YZ or ZX axis, in either object space or world space).
  • ...showed once, or repeated. Independent repeat-control for U and V axis, repeat can be mirror-flipped to avoid discontinuities.
  • ...freely mix 2D (picture file) maps with a set of predefined procedural 3D (perlin noise) solid maps. (Procedurally defined "shaders", written in ATLAST , was planned but never implemented... maybe some day....)

  This allows complex surfaces to be created from simple parts. Decals can be added onto surfaces, textures can be mixed, e.t.c.

• Intelligent map filtering: At the time, most raytracers didn't filter their texturemaps, they let the anti-aliasing functions shoot tons of rays instead, making it very slow. RayTracker accurately filtered texturemaps, and only shot extra anti-aliasing rays on object boundaries (using a hashing mechanism).

• Shadow maps (depth maps) can be used to generate smooth shadows. Naturally, raytraced shadows are also supported.

• Animation supported thru AutoCAD plugin app.

• Advanced materials: Glazing, translucency, alpha-channel in texture maps, e.t.c. all possible.

• Comprehensive library of materials.

• ... and more...

• Note: These might not look like much by today standards - but keep in mind that it was almost 20 years ago, and that I not only made the models and rendered them, I wrote every line of the rendering program myself, and building some of these models in AutoCAD Release 10 or 11 using no solid modelling whatsoever took some doing....

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  Some ref[rac|lec]ting teapots

  The Famous teapot is the benchmark object in Computer Graphics. Naturally, I use it too. Here featuring teapots made of glass (left), diamond (back) and water (front).

  
  

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  A Waxed Floor (640x480)

  This shows the map-mixing capability of RayTracker. The floor consists of two different texture-maps. One with the woodgrains, and another with the "tiles" of the floor. These are repeated at different scales, which means that when one of them repeats, the other does not. The result looks like a very realistic hardwood floor. Finding where the textures repeat is hard. If there would be only one texture map, you could easily see where it repeats (the human eye is very good at picking such things up!)

  Modeled by: Autodesk (but I added the table lamp, book, pencil and bolts on the table)
  

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  2 Bikes (640x480)

  Inspired by "Reds Dream" (by Pixar) I modeled a couple of bikes.

  Nothing really advanced technically, but it was a fairly long render... there are many spokes in the wheel of a bike, I can tell you that.... :-)

  It says "(c) EMT" in the picture, but that's not true, since I don't work there anymore, and they don't have anything to do with RayTracker any more.

  Modeled by:Yours Truly.
  

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  (450k PKZIP'ed FLI animation)

  This is an animation (in Autodesk Animator .FLI format, 320x200 pixels) of Luxo Jr and Red (from "Red's Dream") tossing a ball back and forth to eachother.

  Being a big John Lasseter fan, I couldn't help but model some of his "stars", and put them in the same little "movie"...

  Modeled and Animated by:Yours Truly.
  

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  Knick Knack (640x480)

  While we are at the "Pixar Fan" subject, I simply had to show my (not very good) rendition of the little snowman from "Knick Knack".

  It's not a great model, but, as Depeche Mode has engraved at the center of their first single ["I just can't get enough"]: "It's better than a slap in the face with a wet fish..."

  Modeled by:Yours Truly.
  

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  Coffee Break (640x512) (1280x1024)

  My attempt at maximum photorealism. Please note the coffee stains, the donut crumbs, the blurry blueprint, the half-erased pencil markings with little chips of the eraser beside it, the woodgrain in the pencil....

  The solid object is made with RayTracker's solid modelling operations. The blueprint drawing is the actual drawing which makes that object, saved from AutoCAD as a GIF file, painted blue and blurred in Photoshop, and used as a texture...

  Modeled and so by:Yours Truly.
  

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  Zoot

  This was intended to be an animation, and a long one.... I had the storyboard worked out fine. But with the rendering speed of RayTracker, and events of real life, it never got beyond 150 frames, and only a few models were ever completed. Here is a few:

  Space ship interior (640x300)

  All the readouts are actually .FLI texture maps, which means, they are really animated: Radar scopes radiate, oscilloscopes oshillate, and video screens vidiate.

  Neat touch: The planets, seen in one screen, are rendered in RayTracker. The "Tactical display" on the screen beside it, is the same planets, rendered in RayTracker as wireframe....

  The storyboard for this animation was all done. There would be a cute (robotic-alien-style) little boy sleeping in the spaceship, his dad sitting playing videogames in the chair pictured above. The kid has a vivid dream of a Terminator style alien mashing the ship...

  The Killer (640x480)

  This is the only part of the killer I modelled for that dream sequence...

  The kid would wake up from the dream, scared out of his wits. Jump out of bed, open his toychest (hmm... why are all computer-animated flic's about toys?) and rummage around and find his trusty old laser gun.

  Then he would go out in the corridor, and hear strange noises from the command room (which really is his dad playing videogames, but he thinks it is the alien killer droid he dreamt about).

  At the same time, his dad decides to give his little son a cup of tea. He makes a tray with a teapot (guess which one) on, and is about to enter the corridor... the extremely enlarged shadow of the teapot falls on the corridor wall, the kid thinks it is a monster, and raises his toy laser, arms it and.....

  It's a real pity this animation was never finished!

  Modeled by:Yours Truly.
  

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  Benji mouse (800x600)

  Benji Mouse was an entry for a computer graphics competition, where the winner would get it's picture printed on a mouse pad (in Swedish, "mouse carpet"). Therefore I made this picture, where Benji Mouse demonstrates his nice $1 carpet.

  I didn't win, but I got an honorary mention (and my picture in the magazine), and was supposed to receive a T-shirt. Havn't seen the shirt yet tho... :-)

  Technically, I a most pleased with the Lace curtain. I am not as pleased with the hand-modelled electric cord.

  Modeled by: Yours Truly.
  

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  A Drill (640x480)

  This is a demo AutoCAD drawing, that I've attempted to make photorealistic. Not very advanced stuff. The procedural wood in the handle could be better (the veines are too dark). But overall, a nifty image...

  Modeled by:Autodesk.
  

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  The "Centaur" (375(x2)x564(!?))

  One of the two places in the universe who ever bought RayTracker was a school in the town I live, who had an advanced course in "Technical Illustration". The people there were working with airbrushes, paper, pencils e.t.c....

  One of their assignment was to draw this old vintage 1800 gas engine, called the "Centaur", from the original old blurprints. They had four weeks to do that task: Make the perspective view (using perspective ruler, tables and a pocketcalculator), and then mask it (cutting holes in cover plastic) and airbrush it.

  I borrowed a copy of the drawings, and modelled it in AutoCAD (which wasn't easy, actually). I returned to them a week later, and showed them three renderings of it, including an animation of the thing spinning:

  • (130k PKZIP'ed FLI animation)

  The look on their faces was priceless. There was some amount of fear in it....

  Modeled and animated by:Yours Truly.
  

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  A Guitar (640x480)

  Since I am a music dweeb too, I couldn't resist the temptation to render an electric guitar.... (which is wierd, since I mostly play synthesizers and computers!?)

  Here, the projective mode of the texturemapping is used, to make the wood grains match on the top surface of the guitar (which is a single curved-edge polygon) and the sides (which is a different smoothed polygon mesh). The model has some bugs where these two surfaces meet (or rather, doesn't meet), but what the hell. It's pretty to look at...

  Modeled by:Yours Truly.
  

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  (Actually, this link-image to my homepage you see here, is also rendered in RayTracker....and it's a real model of the house I live in!)

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