Analytical iTwin supports a wide array of section shapes, including parametric sections, custom section shapes, composite sections, and linearly varying sections. RAM Concept supports only two section shapes: solid rectangles for beams and solid rectangles or circles for columns. RAM Concept must therefore create a rectangular or circular approximation for any non-rectangular or non-circular Analytical iTwin section shape.

Analytical iTwin Parametric Sections use a small number of parameters to define the most common section shapes. For column members, RAM Concept maps solid and hollow circular Analytical iTwin parametric section shapes to solid circles. All other parametric shapes for beams and columns are approximated by rectangles.

The following table shows the width and height the RAM Concept rectangular section approximations for each Analytical iTwin Parametric Section Type:

Analytical iTwin also defines Custom, Built Up and Varying section shapes. Analytical iTwin Custom sections are defined by an arbitrary geometric shape. RAM Concept approximates Custom sections by a square of the same area. Analytical iTwin Built Up sections are composites of other parametric or custom sections. RAM Concept approximates Built Up sections by a square with the area of the sum of the areas of the section's components.

Analytical iTwin Varying sections vary shape linearly along a member. RAM Concept approximates a Varying section shape by applying the rules for constant sections to the start of the first varying section segment.

When updating an Analytical iTwin repository, RAM Concept section approximations will appear as changes in the iTwin Analytical Synchronizer update dialog. The Change action on these changes can be set to Always Reject to prevent the Analytical iTwin sections from being replaced.