SectionCutter2 is an ETABS plugin developed to help structural engineers quickly create section cuts and visually review diaphragm shear, moment, and axial force results in a clear, intuitive, and repeatable way.
Rather than relying solely on tabular output or manually defining section cuts one by one, this tool streamlines the process by combining interactive geometry, automated ETABS section cut creation, and visual result plotting into a single workflow.
The goal is simple:
Understand diaphragm force flow faster and with more confidence.
Installation and how to use video:
https://www.youtube.com/watch?v=h55M_A2X-0I
This example demonstrates:
- Selecting diaphragm areas
- Defining section cut spacing
- Automatic section cut generation
- Immediate plotting of diaphragm force results
This example demonstrates:
- Adjusting section cut spacing or direction
- Regenerating results
- Rapid visual comparison of force distributions
Reviewing diaphragm forces in ETABS can be:
- Time-consuming
- Highly iterative
- Difficult to interpret using tables alone
- Error-prone when section cuts must be created manually
SectionCutter2 addresses these issues by allowing engineers to:
- Rapidly define multiple section cuts across a diaphragm
- Instantly see how shear, moment, and axial forces vary spatially
- Validate diaphragm load paths visually
- Iterate on cut locations without repeatedly rebuilding ETABS definitions
This is particularly valuable during:
- Lateral system design
- Diaphragm force checks
- Shear wall load path validation
- Peer review and internal QA/QC
- Design development when layouts are still evolving
- Select diaphragm areas in ETABS
- Define section cut direction and spacing
- Automatically generate ETABS section cuts
- Extract diaphragm force results
- Review results visually using plotted force diagrams
- Refine section cuts and re-evaluate as needed
The application begins by allowing the user to select:
- Diaphragm area objects
- Openings within the diaphragm (shafts, stairs, large penetrations)
These selections define the effective diaphragm geometry used for:
- Section cut extents
- Accurate force extraction
- Avoiding misleading results through voids
Users define:
- Section cut orientation
- Total Number of Section Cuts
- Extents of the cuts across the diaphragm
The tool automatically:
- Extends section cuts slightly beyond the diaphragm geometry to ensure full force capture
- Applies consistent naming and organization inside ETABS
- Prevents duplicate or overlapping section cuts
Key benefit: Consistent section cuts can be created in seconds.
Once defined, SectionCutter2:
- Creates section cuts directly in the active ETABS model
- Extracts force results for selected load cases and combinations
- Retrieves shear, moment, and axial values parallel to the cut direction
All interaction with ETABS occurs transparently in the background.
For each set of section cuts, the application generates:
- Plots of shear, moment, or axial force
- Plots aligned parallel to the diaphragm geometry
- Shaded areas under the curve for intuitive magnitude comparison
- Smooth transitions between adjacent section cuts
This allows engineers to:
- Quickly identify force peaks
- See how forces redistribute across the diaphragm
- Compare different load cases visually
- Catch modeling anomalies early
Alongside the plots, the application provides:
- A tabular view of section cut results
- Tablular results can be copied and pasted to excel for own spreadsheet calculations
- Clear correlation between geometry and numeric output
The table and plots are designed to work together — numbers for precision, graphics for understanding.
Refer to the installer folder or the project releases for installation instructions and packaged builds.
SectionCutter2 supports sloped diaphragms. When working with sloping slabs, it is important to properly define the Section Cut Height Above and Section Cut Height Below values so that the full diaphragm thickness and slope are captured by the section cut.
The vertical span of a section cut is defined relative to the Start Node elevation.
The section cut is centered at the Z-elevation of the selected Start Node and extends upward and downward based on the user-defined heights.
For example:
- Start Node elevation = 10 ft
- Height Above = 4 ft (always positive)
- Height Below = 4 ft (always positive)
The section cut vertical limits will be:
- Lower bound = 10 ft − 4 ft = 6 ft
- Upper bound = 10 ft + 4 ft = 14 ft
In this example, the section cut spans from 6 ft to 14 ft.
Both Height Above and Height Below are positive-only values.
When analyzing sloping slabs:
- Ensure the full sloped diaphragm geometry falls within the defined vertical Z range.
- Increase the Height Above and Height Below values as needed to capture the highest and lowest points of the diaphragm along the section cut.
- If the diaphragm falls outside this Z-offset range, forces may not be fully captured.
- Results are dependent on the accuracy of the ETABS model and load definitions.
- Section cuts are intended for diaphragm force review and engineering interpretation.
- The tool is not a substitute for full code-based diaphragm design checks.
MIT License
Copyright (c) 2026 Austin Guter, representing Retug LLC
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
This product includes software developed by third parties.
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The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.