What is Calculus?

Calculus is a 3D structural modeling tool that runs in your web browser. It is designed for structural engineers who need to create, detail, and share structural models — without installing desktop software.

If you've used tools like Tekla Structures, Advance Steel, or RFEM, you'll feel at home. Calculus covers many of the same workflows: creating beams and columns with parametric profiles, placing bolt groups, defining welds, detailing reinforcement, and exporting to IFC.

Who is it for?

• Structural engineers who need a quick way to model and detail steel or concrete structures
• Teams that want to share models and libraries without managing software licenses
• Anyone who needs to view, edit, or export a structural model from any computer with a browser

What can you do with Calculus?

Model structural parts

Create beams, columns, plates, bolts, welds, and reinforcement bars — all in a 3D workspace with a structural grid, snap points, and orthographic views.

Detail connections

Place bolt groups in array, circular, or custom layouts with full assembly definitions (bolt, washers, nuts). Define welds between parts with shape, size, and contour properties. Create cut parts and cut planes to trim or notch members.

Use standard libraries

Work with built-in catalogs of steel profiles (IPE, HEA, HEB, HEM, UNP, CHS, SHS, RHS, angles, and more), materials (S235–S460, C20/25–C50/60), bolt assemblies (DIN933, M12–M30), and rebar grades (B500B, Ø8–Ø32). You can create custom profiles and share catalogs with your team.

Annotate your model

Add reference grids with labeled axes and levels, construction lines, text comments, marks (labels), and dimensions to communicate design intent.

Exchange data with other software

• Export to IFC 4x3 for coordination with architects and other engineers in BIM workflows
• Import IFC, glTF, or PLY files as reference overlays to work alongside existing models
• Save and share models in the native .calculus format
• Integrate with Tekla Structures using the companion CalculusTeklaLink plugin

How does the model space work?

Calculus uses a single model space. When you open the application, you start with an empty model (with a default grid). You can:

• Create objects directly in the model using the toolbar or keyboard shortcuts
• Open .calculus files to load a previously saved model — objects are merged into the current model
• Import reference models (IFC, glTF, PLY) that appear as non-editable overlays for coordination
• Save the model at any time as a .calculus file that includes all objects, catalogs, and settings

Everything you create lives in this single model space. There are no separate "drawings" or "views" — you work directly in 3D. The model is autosaved in your browser, so you can close the tab and come back later without losing work.

What makes Calculus different?

• No installation — Open a link and start modeling. Works on any computer with a modern browser.
• Familiar workflow — If you know Tekla Structures, you already know most of the shortcuts and concepts.
• Fast and lightweight — Built for performance with on-demand rendering and background geometry processing.
• Open format — The .calculus file is a readable JSON file. Catalogs and models can be freely shared.