Terms of Service

These terms cover buying OpenBillow, support, and this website. They are provided by Pipelineflow Ltd (company number 16495997, England and Wales). By buying or using the support service you agree to them. The Licence governs the preset pack; these Terms of Service govern the purchase, support and the website. Also see Privacy and Company details.

What is free and what you pay for

The OpenBillow add-on is free and open source under the GPL-3.0-or-later. Anyone may use, change and share it, and nothing in these terms limits those rights. What you pay for is the preset pack and materials (under the Licence) and support.

Price and purchase

During early access the price is $10 on Gumroad. At launch it will be about $20. The price may change for future buyers; it never changes for a purchase already made. It is a one-time purchase, not a subscription. Payment is handled by Gumroad under its own terms.

Licence key

You get one licence key per purchase. It is for one person and may be used on any of your own computers, including your render farm. These terms set no hard device limit, but the Licence sets an activation limit and sharing keys with other people is prohibited. We can switch a key off if it is refunded, charged back or shared.

Refunds and your rights

Refunds follow UK consumer law. You normally have 14 days to cancel a purchase, but for digital content that right ends once the download starts, with your agreement and acknowledgement that you lose it. If the content is faulty or not as described, you keep your statutory right to a repair, replacement or refund. Nothing here affects your statutory rights. To ask for a refund, email support@pipelineflow.co.uk. Refunded keys are disabled; we re-check keys with Gumroad weekly.

Support

A valid key lets you send support requests from inside Blender or by email to support@pipelineflow.co.uk. Support is by email on a reasonable-endeavours basis. We aim to reply within 2 working days. Every reply is written or checked by a person. We cannot guarantee that a problem can be fixed. Support covers installing and using OpenBillow, and bugs in it. It does not cover general Blender help, other add-ons or your hardware. Requests are limited to three a day per key.

Activation

To download presets or send support requests, the key must be activated in the add-on. A key can be activated on up to five new computers in any twelve months; contact support if you have replaced a computer. We store a one-way hash of your computer’s system identifier for this (see Privacy).

Render farms

Render farm nodes need no key. The solver runs from the command line, so a node can bake without being activated. Only downloading Scene Packs and sending support requests need an activated key.

Studio licence

Studios can buy a Studio licence: £295 for the first year and £120 to renew. It covers up to 10 named users, the three launch Scene Packs (Gas, Fire and Liquid), 12 months of support and 50% off later packs. There is one named contact for the studio, and the same reply target as everyone else. It is sold by email: write to support@pipelineflow.co.uk and we send an invoice from Pipelineflow Ltd to pay by bank transfer. An invoice is available on request. Studio keys can be activated on more computers than an individual key (25, for up to 10 named users).

Requests for new looks

Requests for new looks are welcome and may be added to a pack. Custom or exclusive work is not offered.

Requirements

OpenBillow needs Blender 4.5 or later and an NVIDIA GPU with a recent driver. It is not guaranteed to work on other setups, and Windows is not yet fully tested. Please check the requirements before buying.

Early access

OpenBillow is in early access. It works, but it is unfinished: features can change and there may be bugs.

Liability

The add-on is provided as it is, as the GPL says. Simulations are heavy: always save your work before baking. Our liability for the Presets is set out in section 8 of the Licence. For support and the website, to the extent the law allows, Pipelineflow Ltd is not liable for lost files, lost time or indirect losses, and its total liability for a purchase is limited to the price you paid. Nothing here limits liability that cannot be limited by law, including for death or personal injury caused by negligence, fraud, or your statutory rights as a consumer.

Trademarks

Blender is a trademark of the Blender Foundation. NVIDIA, CUDA and Warp belong to NVIDIA. OpenBillow is an independent product and is not made, endorsed or sponsored by either.

General

These terms are governed by the law of England and Wales. We may update them; the terms in force when you buy apply to your purchase.

Last updated: 3 November 2026.