VDC Plugins for Revit

Problem

VDC Plugins is sold by subscription, so two things have to work together: tools that run reliably inside Revit, and a licensing system that only lets users with access in.

My role

I'm the lead developer of the add-in suite, and I contribute to UtahBIM's subscription app and storefront. I work with UtahBIM as a contractor through Upwork.

Approach

• Add-ins. About 10 tools in C# on .NET 8, for Revit 2025 and 2026, shipped in one Inno Setup installer.
• Licensing gate. Every tool goes through a shared per-tool gate that blocks unless access is confirmed. Tools from another developer were brought onto the same structure and gate, with fixes along the way.
• Ports and rules. Logic that lived in Dynamo and Python was ported to C#. Slope checks follow IPC Table 704.1, with the tolerance documented.
• Web side. Each plugin has a slug in a registry. Stripe handles organisation and personal subscriptions, and webhooks follow each subscription's lifecycle by its ID, which closed gaps where access had leaked. The storefront has a free-trial flow and installer downloads, and deploys with Docker and Prisma.

public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
{
    AccessDecision decision;
    try
    {
        decision = TheToolkitGate.Evaluate(AppSlug, commandData.Application.MainWindowHandle);
    }
    catch (Exception ex)
    {
        // Anything unexpected inside the gate blocks the command (fail closed).
        decision = AccessDecision.Blocked("The license check failed unexpectedly.\n\n" + ex.Message);
    }
 
    if (decision.Outcome != GateOutcome.Allowed)
    {
        TheToolkitGate.ExplainDecision(decision, CommandDisplayName);
        message = decision.ShortSummary(CommandDisplayName);
        return Result.Cancelled;
    }
 
    return ExecuteCommand(commandData, ref message, elements);
}

Outcome

VDC Plugins is a commercial product, sold at vdcplugins.com.