Chapter 3 ■ advanCed 3d Content rendering: 3d asset ConCepts and prinCiplesIn Blender, some 3D modelers (people, not software) will make the mistake of trying to expose a
seam, or a sharp edge, in their 3D geometry by actually splitting the edge of the 3D geometry itself, which
will achieve this visual effect but which could also cause a problem down the line during a 3D geometry
topology refinement work process. If you’re familiar with the term topography used in mapping, topology
is very similar, referring to how 3D geometry is constructed and, therefore, how it will be rendered since a
rendering engine is “math-based,” just as 3D geometry is.
The topology of a 3D model is the construction of the 3D geometry, that is, where vertices, edges, and
faces are placed relative to each other, or it’s the construction of spline-based organic 3D models where
control point, handles, and similar spline-based topology have been placed (and the order in which they are
placed). In other words, 3D modeling is complex!
Having to split your geometry edges to achieve a seam can be avoided by instead using the Mark Seam
or Mark Sharp edge modifier in Blender. These particular Blender modifiers are actually smoothing group
based and therefore achieve this smoothing (or edge seam) effect without actually affecting the 3D geometry
topology.
A Blender modifier is applied just before rendering and therefore does not affect the actual
mathematical topology of your underlying 3D geometry. A Blender modifier is always a more flexible 3D
content creation approach because it applies smoothing (or any other desired effect) at the rendering engine
level, not at the 3D geometry topological level, leaving your 3D mesh intact. As with anything in Pro Java 9
Games Development (and IoT design), simpler will always be better if you can achieve a desired effect and
end result because simpler equals less processor overhead.
Skinning Your 3D Model: 2D Texture Mapping Concepts
Once your 3D geometry, which is the foundation for your 3D model is completed, you can apply texture
maps to it to create a solid appearance for your 3D model and add detail and special effects to it to make
its appearance more and more realistic. If you are wondering what the difference is between 3D geometry
and a 3D model, 3D geometry is just the mesh or wireframe, whereas a 3D model could have (should have)
Figure 3-3. Set edge smoothing in Blender using the Edges menu (Ctrl-E when in Edit Mode) command called
Mark Seam or Mark Sharp