  The SMARDDA software library is used to model plasma interaction with complex
engineered surfaces. A simple flux-tube model of power deposition necessitates
the following of magnetic fieldlines until they meet geometry taken from a CAD
(Computer Aided Design) database. Application is made to 1) models of ITER
tokamak limiter geometry and 2) MASTU tokamak divertor designs, illustrating
the accuracy and effectiveness of SMARDDA, even in the presence of significant
nonaxisymmetric ripple field. SMARDDA's ability to exchange data with CAD
databases and its speed of execution also give it the potential for use
directly in the design of tokamak plasma facing components.
