Spline's Per-Seat Math: Why 3D Delivery Margins Depend on Who Sits in the Editor

Spline charges per seat ($15 Hobby, $30 Pro, $70 Max monthly), so the agency margin question is not whether 3D work sells but how few people you can put in the editor per client deliverable. A Pro seat at $30/month that ships one interactive web embed per quarter costs the agency roughly $90 in tooling against a $580/mo Spline Starter 3D Presence retainer, which is the entire arbitrage. The catch is that Spline publishes no white-label program, so client-facing embeds carry Spline branding and the retainer has to be sold on the experience, not on a rebranded product.