ISM 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 ISM section shape.

ISM 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 ISM 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 ISM Parametric Section Type:

ISM also defines Custom, Built Up and Varying section shapes. ISM Custom sections are defined by an arbitrary geometric shape. RAM Concept approximates Custom sections by a square of the same area. ISM 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.

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