  The engineering design of a particle detector is usually performed in a
Computer Aided Design (CAD) program, and simulation of the detector's
performance can be done with a Geant4-based program. However, transferring the
detector design from the CAD program to Geant4 can be laborious and
error-prone. SW2GDML is a tool that reads a design in the popular SOLIDWORKS
CAD program and outputs Geometry Description Markup Language (GDML), used by
Geant4 for importing and exporting detector geometries. Other methods for
outputting CAD designs are available, such as the STEP format, and tools exist
to convert these formats into GDML. However, these conversion methods produce
very large and unwieldy designs composed of tessellated solids that can reduce
Geant4 performance. In contrast, SW2GDML produces compact, human-readable GDML
that employs standard geometric shapes rather than tessellated solids. This
paper will describe the development and current capabilities of SW2GDML and
plans for its enhancement. The aim of this tool is to automate importation of
detector engineering models into Geant4-based simulation programs to support
rapid, iterative cycles of detector design, simulation, and optimization.
