# Pillar Shape

In CPillar , the pillar geometry can be modeled as either a:

• Rectangular Pillar
• Polygonal Pillar

The Pillar Shape can be selected in the Project Settings dialog.

NOTE: Polygonal Pillar shape is selected by default. When modeling a Polygonal Pillar, only Rigid Analysis Method can be selected. Elastic and Voussoir Analysis Methods are formulated specifically for a Rectangular Pillar. See the Analysis Method topic for more information.

## Rectangular Pillar

CPillar computes the factor of safety for a Rectangular crown pillar formed by:

• Some length (x) and width (y),
• Some uniform height (z), and
• Vertical abutments (for a rectangular pillar).

A typical rectangular problem geometry is illustrated below:

Typical rectangular pillar geometry for CPillar analysis.

## Polygonal Pillar

CPillar computes the factor of safety for a Polygonal crown pillar formed by:

• At least three unique vertices (x, y) that define a 2D polygon,
• Some uniform height (z), and
• Vertical abutments, or slanted abutments defined by Trend and Plunge.

A typical polygonal problem geometry is illustrated below:

NOTE: Only Rigid Analysis is allowed when using Polygonal Pillar shape. The Analysis Method will automatically be set to Rigid if Pillar Shape = Polygonal Pillar. If Pillar Shape changes affect abutment material assignment, then the material assignment will be reset to defaults (i.e., all abutments will be assigned the first Material Property)