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seeing structures

Professor Susan M. Reynolds


Seeing Structures is the first-generation of a new, online repository of interactive teaching models that facilitate visualization of engineering mechanics problems. The project scope includes content from Statics, Mechanics of Materials, and Structural Analysis. To date, the majority of the models have been created to support the Mechanics of Materials course at Colorado School of Mines.


Susan's Homepage


About the project


When COVID-19 necessitated remote teaching, I needed to quickly convert timeless hands-on teaching props into equally effective online equivalents.

Unable to pass around a foam beam to demonstrate concepts such as “plane sections remain plane,” or an annotated wood cube for the sign convention for shear stress, I created dozens of interactive CAD models.

The first generation of the Seeing Structures models have been uploaded to SketchUp’s 3D Warehouse.

You can view the Seeing Structures repository at

The models support student learning by enabling visualization of 3D concepts in a dynamic, interactive interface.

Students can connect the abstraction of an analytical model while viewing the practicality of construction detailing.

My objective is to share my work across the engineering education community. To use my models in your class, I only ask that you acknowledge that they were created by Professor Susan Reynolds as part of the Seeing Structures project.

I am in the process of formally designating each visualization with a Creative Commons license.




1. Internal normal force, shear force, and bending moment in a beam element

2. Average normal stress (example problem)

3. The stress cube and the stress element

4. Representation of a body as a continuum of stress cubes; normal stress on a stress cube

5. Hooke’s Law (the spring experiment)

6. Fixed-free bar subjected to axial tension

7. Sign convention for planar shear stress

8. Sign convention for all 3D normal and shear stresses

9. Poisson’s Ratio

10. Axial deformation of a simple axial member

11. Axial deformation of a compound axial member

12. An unconstrained beam subjected to thermal effects

13. A spherical pressure vessel

14. A cylindrical pressure vessel

15. A composite steel and concrete (co-axial) column

16. A rigid beam supported by deformable (flexible) cables

17. Deformations that result from shear force and from bending moment

18. Centroid / center of area (checkerboard analogy)

19. Strong-axis bending vs. weak-axis bending of a beam

20. Cantilever beam subjected to an applied moment (derivation of the flexure formula)

21. Distribution of flexural stress on a cross-sectional plane for positive and negative bending

22. Derivation of the formula for transverse shear stress in a beam

23. A solid cylindrical shaft subjected to torsion

24. A hollow cylindrical shaft subjected to torsion

25. Comparison of a stocky column and slender column (both pin-pin)

26. Pin-pin columns and bracing – small wood structure

27. Wood column supported by through-bolts

28. A wall-mounted shelf

29. Members susceptible to stress concentrations due to a hole, a notch, or a taper

30. An eccentric compressive force (combined axial and flexural stress)

31. Combined stress: an allen wrench in static equilibrium

32. A C-clamp compresses a block of wood

33. A 3D bent pipe subjected to moments and forces

34. Stress on an inclined plane

35. Stress transformation in 3D: rotation to principal planar stresses in xy, yz, and xz