INFORMATION FOR

Prospective Students
Current Students

INFORMATION

Home
Group Members
Modelling
Devices
Downloads
Publications

PROJECTS

Funded
Undergraduate
Postgraduate

QUICK LINKS

Optical Devices
Ghent LC Group
GID

Troubleshooting

Common causes of program failure are:

• Improperly set boundary conditions in mesh.txt. For 3D problems, a triangular surface mesh is used to set the boundary conditions, but by default GID does NOT output these surface elements. In GID the following procedure is necessary to force this output: Meshing > Mesh criteria > Mesh > Surfaces, then select all surfaces and press ESC. For 2D problems the same procedure is required for lines.

• All volume elements must be assigned a material number, either that of a Liquid Crystal Domain or a Dielectric. If a dielectric region exists please ensure that it's permittivity is defined in elastic.i. Otherwise zero permittivity is assumed, which causes failure of the potential solver. Likewise the LC properties must be also defined in elastic.i. Mistakenly setting delta epsilon greater than esplow also causes problems.

• Structures must be defined so that the alignment surfaces lie in the x-y plane. This is crucial when setting intial boundary conditions. Alignment surfaces must be continous across the upper and lower surfaces of LC domains.

• Alignment Surfaces must NOT be assigned above, beneath or within dielectric regions.

• At least one electrode must be exist in the meshed structure.

• Although opposing faces to which periodic boundary conditions are applied need not necessary be identical, when they are the condition is more strongly enforced. In GID this can be achieved by creating Separate Volume Contacts. However, Tetgen does not support this feature.

This page last modified 2 June, 2006 by r.james