The search for a perfect model. - A wake-up call from Brian K. Drescher.Has everyone gone polygon crazy? Aren't there other any other ways of visualizing 3D images than the POLYGONS FROM HELL? Lets take at look at another universe of computer modeling and lighting...CSG...Constructive Solid Modeling. A simple route to the perfect model (This will have no effect on Claudia Schiffer).
What ever happened to perfect simplicity? In the eons old development of computer graphics a very interesting element seems to be forgotten or ignored...SOLID MODELING! What is the force behind the resistance to using solid 3D objects in place of billions of polygons to describe a three-dimensional object or space? And what the heck exactly is CSG? Let's take a vote. What do you think what would be the best way of describing a simple object such as a ball in 3D space. To use thousands of polygon surfaces to "smooth out" the surface, plus the location in 3D space, or to give only the position in 3D space plus the radius of the ball. Yes, you don't have to be a nuclear physicist to realize the answer....play it simple...CSG. Constructive Solid Modeling has the advantage over polygons simply because a CSG model is always PERFECT! The surfaces contain no vertex rendering errors because the surfaces of CSG models are infinitely perfect.
TO ZOOM OR NOT TO ZOOM
Think of the problem of the thousand to one zoom. You want to fly your incredibly complicated space vehicle onto the surface of an alien moon. Your model consists of millions of complex descriptions of the surface locations of your model (the surface). The planet that you are about to approach consists of a "geosphere" ball made up of thousands of polygons. As you fly your virtual "space ship" towards the surface, the facets of the geosphere become painfully visible. What do you do? Increase the subdivisions of the model, or "fudge" the approach with motion blur to hide discontinuities of the surface...With CSG this would never have been a problem because the surface was infinitely perfect. There are no polygon subdivisions in CSG, so without any further thought you may proceed with landing.BOOLEAN BOOGIE MEN
Boolean algorithms are very ancient (turn of the century) mathematical descriptions of spatial unions, subtractions, and intersections by the mathematician Anthony Boole. In his time these descriptions were of volumetric interactions of overlapping 2D space. Later, as applied to 3D computer graphics, the same calculations describe the complex interaction of virtual objects that make up the images that we know in CGI interacting in 3D space. Solid modeling is the basis for 3D Boolean operations in the ancient (60's) birth of CGI. All of the popular vector based computer graphics programs have assimilated these algorithms into their software, but polygon based mathematics don't really lend themselves to Mr. Boole's logic. Because a polygon based object has no real volume, and because the surface is divided into indescript planes and vertices, a Boolean operation loses its pure mathematical solution...to extract a perfect volume.SOLID REALITY
The advantage of using solids for modeling becomes very clear when you have to make a glass or transparent object. Because the elements you are using to make your model have real mathematical volume, making a wine glass look real is automatic. Because of the true volume of a solid objects description you don't have to worry about calculating the refraction index of a glass object based on the outer and inner polygon surfaces. It has automatic "weight" of light bending. You don't have to trick the effect. For CADCAMMERS the volume of the solid space calculations work perfectly to calculate actual material loses during cutting operations such as drilling and milling because the volumes cut away are actual and not interpolated.THE DOWN SIDE OF CSG MODELLING
The biggest problem with CSG modeling is that the structure of the solids has to be "cooked into" the basic structure of the modeling process. You have less control over beveled edges, chamfered edges, wild variations of structure (even though NURBS were born from CSG). But this problem has been solved in recent years...CSG is ready to be REBORN...the rebirth of the BIRTH of computer graphics.A WAKE UP CALL!!
I worked for a company in Holland that based it's modeling technique on solid modeling. That company was called ElectroGIG. If any of you had ever seen images from that software you know that there is power behind the concept. GIG has since died a quiet death for many reasons, but the concept was good...if you are in search of the perfect CGI modeling technique....look into CSG. If you would like to hear some more ranting and raving regarding CSG give me a call. Or if you are a serious software developer looking for the next route in computer graphics...call me for a map to the new world!