It is very vital that the solid model must undergo the process of model verification to have consistency check whether it conforms to standards and actual shape. This is needed because there are several ways for getting errors in the process of solid modeling. To name few in this direction are errors can take its presence while transporting models across systems, errors can be introduced even during modeling process, the exchange format files like stereolithography tessellated language formatted files may have errors introduced in it due to missing edge or facets and so on.
So it is very essential to carry out the process of model verification. The process of model verification must be done once the model is exported from one system and before importing into another system.Methods of Model Verification and Requirements : There are several methods in model verification and requirements. Some of them are model visualization, dimensional measurements, property computation, thickness check, simulated radiography and Euler's equation. Let us see each of these in detail.
Model Visualization : It is essential to carry out the checking process in model verification at a visualization level. In this model has to be viewed visually in various ways orthographic, isometric, cross-sectional, hidden line or shaded image. It is also essential to visualize the model in various angles by rotating it or by zooming it across various surfaces to check for conformance with actual.
Dimensional Measurements : The next important step in model verification is to check the dimensions like distance, angle between two edges or between faces and so on, to have consistency maintained between resulted model and actual.
Property Computation : The attributes of property include in it weight, volume, center of gravity and moment of inertia. For instance weight of the resulted solid model must be compared with actual weight to record errors in the process. The process requires accurate data to be recorded for which even the actual solid model taken must be free of defects in manufacturing.
Thickness Check : There are several models which have many internal surface and features embedded in it. For such models it is very essential to carry out thickness check as part of model verification to check for modeling errors. The approach of this step requires having various cross sections and then measure the distance between two ends. Recent approaches like color-coded thickness map make the process carried over the whole model to be checked easily with greater efficiency.
Simulated Radiography : The stereolithography-tessellated language has errors associated with its formatted file. To find these errors the simulated radiography is a widely used method. Thus these help in efficient simulations of process and feature recognition. The method makes, use of parallel ray being passed in a particular direction into the model and the model thickness in this direction is shown as gray shade. In this representation if there are any breaks in lines it denotes the errors in the model.
Euler's Equation : The Euler's equation is given as
V+F = E+2
In the above V denotes vertices, E denotes edges and F denotes faces. This model is ideally used across all facetted solid models.