What is an in-CAD engineering tool?
An in-CAD engineering tool reads data from the model (dimensions, materials, loads, connections), applies your engineering rules or calculations, and writes results back into the model, drawing or report. The engineer never leaves the CAD environment.
Examples of engineering tools
- Sizing tools: shaft, beam, duct, pipe or cable sizing from loads and codes.
- Selection tools: pick motors, bearings, fasteners or valves from catalogues, then insert the correct model.
- Weight and centre-of-gravity reports for lifting, shipping and balance.
- Tolerance stack-up calculators using dimensions picked from the model.
- Design assistants that suggest standard sizes or warn about manufacturability.
- Cost estimators based on material, features and processes.
A development process that works
1. Capture the engineering method
Start from the existing spreadsheet or hand calculation. Document formulas, code references, units, assumptions and limits. Have a senior engineer sign it off.
2. Separate calculation from CAD
Write the calculation as an independent, unit-tested library. This makes it verifiable and reusable in a web app or another CAD system later.
3. Map model data to inputs
Decide where each input comes from: model parameters, custom properties, selection by the user or an external database.
4. Design the interaction
A palette where the user selects objects and sees results live is usually best. Show warnings clearly when values exceed limits.
5. Write results back
Update parameters, insert components, add annotations or generate a calculation report in PDF or Excel for records.
Example: a simple sizing rule
// Business rule kept independent of any CAD API
public static double RequiredShaftDiameter(double torqueNm, double allowableShearMPa)
{
// d = cube root of (16 T / (pi * tau)), result in mm
double t = torqueNm * 1000.0; // N·mm
return Math.Cbrt(16.0 * t / (Math.PI * allowableShearMPa));
}The CAD adapter reads torque from a custom property, calls this function, then selects the next standard shaft size and updates the model parameter.
Building trust in the tool
- Validate results against known hand calculations.
- Show the formula and inputs in the report.
- Keep a version number of the calculation method.
- Never hide warnings or silently clip values.
An engineering tool must be transparent. Engineers are responsible for the result, so they must be able to check it.
Turn your know-how into CAD tools
ENGIMANDI turns engineering spreadsheets and methods into robust in-CAD tools for SolidWorks, Inventor and AutoCAD, Revit MEP and Creo.