Render the exact product your customer built
When your customer presses the button, the SDK renders the scene as it is on screen: their fabric, their legs, their camera angle. You never have to render every combination ahead of time.
Show a preview while it renders
A quick, grainy preview shows up while the final image is still rendering, so there is something on screen before the customer moves on. Job events and previews are covered in the rendering doc.
Safe to put behind a public button
Your server creates each browser token with an expiry, a render count and a spend cap, so a visitor on a public product page can only spend what you allow. How tokens work is in auth & keys.