The particle tracking techniques used in the combinational geometry package of MCBEND have certain potential limitations:

• Only bodies defined by equations that can be efficiently solved can be employed.
• Attempting to model certain replicating and complex components in a realistic manner can result in tracking inefficiencies due to the large number of boundaries involved.
• The task of composing and checking input data for such a model is a formidable one.
• Smearing out spatial detail introduces systematic errors of unknown size.

An alternative tracking strategy exists in MCBEND in the form of special hole geometries which provide additional geometric complexity.

 

Hole geometries employ an algorithm called Woodcock tracking to perform the Monte Carlo simulation, which replaces the conventional ray tracing approach used by combinational geometry modelling.

 

The Woodcock algorithm enables much more complex structures to be modelled by needing only to evaluate the functions used to define them rather than solve equations. Hence such shapes as a screw feeder and a set of spiral blades become feasible.

 

In addition, regular arrangements can be more easily specified using hole geometries, saving time and reducing the scope for user error.

In the majority of cases as well, Woodcock tracking is more efficient than ray tracing

Hence in summary, hole geometries are used:

• to model complex shapes and combinations that are impossible to model with simple body options (i.e. increase the accuracy of the model)
• to model other shapes and combinations more easily than with simple body options (i.e. increase the efficiency of the user)

The combined hole/simple body MCBEND geometry package enables complex models to be readily constructed with minimum need for approximation

 

Many Hole types are available, a selection of which are shown here. The same hole geometry package is available in MONK.

 

Click here for an Introduction to the Hole Geometry Package.