Blender 3D: Noob to Pro/Meshes and Edit Mode. From Wikibooks, open books . If you haven’t previously studied 3D graphics, technical drawing, or analytic. Blender 3D: Noob to Pro/Normals and Shading. From Wikibooks, open books.
|Published (Last):||15 May 2015|
|PDF File Size:||14.32 Mb|
|ePub File Size:||18.89 Mb|
|Price:||Free* [*Free Regsitration Required]|
Open a new Blender document. The result will be niob angular, as shown to the right, not round like you would expect a sphere to be. Now look in the Toolshelf for the shading buttons: As you can see, the surfaces of the object look a lot smoother and curved, even though the outline or silhouette is just as angular as before. Ensure the UV sphere object is selected, and you are in Edit mode.
Look for the Mesh Display ppro, and find the settings for Normals.
If you check both icon boxes, the display of the UV sphere should change to look something like the image to the right. Those spiky little lines are the normals ; the green ones in the middle of each face are face normalsthe blue ones protruding from each vertex are vertex normals. In the physical theory of light, the normal is a line perpendicular to the surface blneder the object the light is hitting.
When your eye or the camera C is positioned on a plane through the normal of a particular surface observing blsnder certain surface point P illuminated by a coplanar light source Blemdera specific amount of light will be reflected and hence be registered by the camera depending on the physical characteristics of the surface.
Blender 3D: Noob to Pro/More Mesh Editing Techniques – Wikibooks, open books for an open world
The observed intensity of reflected light is at a prp if the angle C-P-L is divided into two equal halves by the normal. In the real world, a lot of surfaces are curved or otherwise not flat.
But a mesh can only be made up of straight edges and flat faces. So how can it represent an object with a curved surface? When you added the UV sphere to your scene, you had the option of specifying how many segments and rings it was made from. The more of those present, the closer the geometry approximates a curve.
However, the more there are, the longer the render will take, and the more memory the model will consume to hold information about all the extra vertices, edges and faces. It applies a trick called Phong shading.
Instead of doing the lighting calculation based on a normal for each face as the physical theory says you should, it starts with a normal assigned to each vertex, and interpolates the normal at each point on a face from the vertex normals at its corners, based on the distance at that point to those corners. This completely violates the laws of physics. But as you can see, the results look rather good, with relatively little extra computation involved, much less than actually generating all the extra geometry.
Blender 3D: Noob to Pro/More Mesh Editing Techniques
As you learn more about computer graphics, you will come across more tricks like this. Physically accurate modelling is still very difficult to do, even with modern computers, and the results may not look all that good. But by adopting a bit of lateral thinking that goes completely against physics, we can often, ironically, come up with much more realistic-looking results.
If you have been adding lots of vertices, edges and faces to your mesh, you may end up with discontinuities in smooth shading causing unsightly blotches, as shown to the right.
Assuming your mesh is constructed properly e. Re-render the scene to blener the shading discontinuity has disappeared. In all other modes, it opens a new default Blender document!
Blender 3D: Noob to Pro