Page 8 of 12
When I ended our last lesson, I pointed out that the sphere was smooth and did not show vertices along its silhouette (in English, the outline looked circular and not like a bunch of straight vectors connected). In reality, that is, contrary to what you see on screen, 3D models are composed of straight line vectors and/or polygons—at one point of modeling or another, and not the smooth flowing shapes you might see onscreen. Why? Because 3D shapes can have hundreds of undulations along its surface, and it is most economical from a computing standpoint to create polygons to describe the surface changes in direction. By default, when you create a sphere for the first time in trueSpace, the sphere is made up of a lattice that are 8 in number up and down (latitudinal) and 8 units from side to side (longitudinally). Now, if we were to view this sphere from a sufficiently distant standpoint, it might look fine rendered, when its structure is of a resolution of only 8 by 8. However, as we've seen (up close) the sphere looks funky when this few number of vectors describe a purportedly smooth sphere.
By the way, if you check into figure 30 again, you'll notice that Bouton pulled a fast one and the spheres are round and not faceted in appearance. How do you do that?
1.) Right-click and hold on the objects pull-down menu on the toolbox until your cursor is over the sphere icon, and then release. You'll get a menu titled "Sphere", with fields for Longitude and Latitude, and you have not yet littered the workspace with another sphere by using the right-click+drag technique.
2.) Type 35 in both the Lat and Long. Fields and then get your view set up in the window so you can see the creation of a new sphere. Me? I deleted the spheres from lesson 3, having lost my amusement for reflective spheres. I'd recommend an overhead view; zoom back as you've learned to do in past lessons so you can see the camera from this view.
3.) Now, click on the Sphere icon. Voila! A new sphere is created that looks like a very dense wireframe. Perhaps the density (the resolution) for the mesh is overkill for a simple rendering, but rest assured that if you want to zoom way in so only part of the surface is visible, like a satellite photo of the earth, the sphere will be perfectly smooth. I'd recommend a density of about 15 for long and lat for most spheres you want to be smooth.
Okay, now what do you do when you've already created or imported a mesh that's blocky looky from too few vectors? You right-drag on the divisions pull-down on the toolbox, and let go when your cursor is over the smooth quad divide icon, as shown in figure 31.
I'm not a math wizard, so I cannot tell you what, at any given resolution of vectors are the interior angles of this sphere, but I can tell you that any angle is greater than 80 degrees. So what you do is specify an amount in the subdivision menu's field, choose the sphere with the Pick tool, and then click on the Smooth Quad Divide icon, as shown in figure 32.
In figure 33, you can see that the coarse sphere is now more refined, with additional latticework in its mesh, and if you want to try this yourself, go for it:
Create a coarse (8 by 8) sphere, set the subdivision angle, and then perform a smooth quad divide on the sphere. Then render it and see how you feel about its smoothness. It must be said that if you are creating a sphere from the get-go, defining a high resolution is better than subdividing it later.