💡 Concepts

The ideas behind the components - why a model is built the way it is, and which element and analysis to use.

These pages explain rather than instruct: why an Alpaca4d definition is put together the way it is, what the axes, signs and units mean, and how to choose between elements and analyses. For the steps, see the how-to guides; for every input, each component's own page in the reference.

• How a model is built: from material to results, and what each stage hands to the next.
• Axes and signs: global and local axes, and which way the forces point.
• Units: what Alpaca4d works in, and what it shows.
• Which element: beams, trusses, shells, bricks and tetrahedra.
• Which analysis: static, modal, buckling, time history, moment-curvature.
• Alpaca4d and OpenSees: what happens when an analysis runs.
• Benchmarks: Alpaca4d against beam, shell and brick theory.