248. STL file format
STL file format is commonly used rapid prototyping technology file formats, and we talk about the rules and identify her.
Stl file rule:
1. A total Vertex flat ground rules for a small triangle adjacent to any vertex not fall flat on the edge of a triangle
2. Orientation of rules for each small triangle plane, the vector must be out, three vertices of the vector into the direction determined by the right hand rule, but also for the small triangle adjacent plane orientation conflict can not appear
3. Every little value rules the vertex coordinates of the triangle must be positive, zero and negative numbers are wrong
4. Full of rules, all in three-dimensional model of the surface must be covered with small triangular plane, without any omissions.
Disadvantages:
1. A violation of the triangle vertices were
2. Errors cracks or holes
3. Triangle too little or too much
4. Small features are missing or wrong.