How to compute a part property

Mattéo_Le_Gall

Hello, I would like to calculate the price of a part based on its mass and its price/kg. I created a property (type List) to select the price/kg of the supplier. The display is the supplier name and the value is its price/kg.

I want to code a feature that get this value, multiply it by the mass of the piece and return the price of the piece to visualise it in my BOM.

Here is the script I get from an LLM but when I create my property and select this feature as the property function source, the cases of the column of the property in the BOM returns "no value", even if the supplier and the mass are known.

FeatureScript 2615;
import(path : "onshape/std/common.fs", version : "2615.0");

annotation { "Property Function Name" : "getCoutMatiereBrute" }
export const getCoutMatiereBrute = defineComputedPartProperty(function(context is Context, part is Query, definition is map) returns number
{
// 1. Lire le prix au kg depuis la propriété "Prix au kg fournisseur brut (€/kg)"
const prixStr = getProperty(context, {
entity : part,
propertyType : PropertyType.PART,
propertyName : "Prix au kg fournisseur brut (€/kg)"
});

// 2. Convertir string → nombre
var prixKg = 0.0;
if (isStringLiteral(prixStr))
{
    prixKg = stringToNumber(prixStr);
}

// 3. Lire le matériau de la pièce
const material = getProperty(context, {
    entity : part,
    propertyType : PropertyType.PART,
    propertyName : "Material"
});

// 4. Obtenir la densité (kg/m³)
const densite = lookupTableDensity(material);

// 5. Calculer le volume (m³)
const volume = evVolume(context, { entities : part });

// 6. Calculer la masse (kg)
const masse = volume * densite;

// 7. Retourner le coût brut (nombre sans unité)
return prixKg * masse;

});

Thanks for your help

MichaelPascoe

Before digging into your FeatureScript, have you configured the custom property in your company settings? "Prix au kg fournisseur brut (€/kg)"
Your company will need to have access to Onshape's paid subscription in order to create custom properties.

Caden_Armstrong

There are multiple issues with your code, and yet another example of why you shouldn't use an LLM.
No LLM can produce working featurescript code.

getProperty doesn't even have a "propertyName" parameter
lookupTableDensity → doesn't exist in standard code
getProperty to string conversion is a mess and all wrong…

MichaelPascoe

Caden's right. If you really need this functionality, I suggest either learning how to FeatureScript the right way.

• Onshape's FeatureScript Fundamentals Course.
• CADSharp FeatureScript Course.

Or hire a developer that already knows it:

• SmartBench
• CADSharp

In the future, Onshape's AI Advisor may have knowledge of FeatureScript and App development.
But at the moment you will not be able to use LLM's very well for FeatureScript.