Sketch CFD

Sketch CFD Support

Contact us

Email:

In the app, Menu > About Sketch CFD > Email support opens an email that already lists the app version, device model, iOS version, and purchase ID. You can change it before you send it. We answer in English, usually within two business days.

Please include:

  • the app version and build (Menu > About Sketch CFD);
  • your device model and iOS or iPadOS version;
  • what you did, what you expected, and what happened;
  • a screenshot, if it helps;
  • for a problem with a sketch, the sketch file, if you are happy to share it (Menu > Projects and files > Save as a file);
  • for a purchase question, the purchase ID (Menu > About Sketch CFD).

Never send us your Apple Account password or payment card details.

What is Sketch CFD?

Sketch CFD is an educational tool for learning computational fluid dynamics (CFD) from simple sketches: draw it, then simulate it. Draw walls, inlets, fans, filters, heaters, and gas sources on the screen, or photograph a sketch drawn on paper. Then watch the flow, gas mixing, heat, and particles develop in two dimensions. It runs on iPhone and iPad with iOS or iPadOS 16.4 or later, in English.

What is free, and what does Sketch CFD Pro add?

Free: run and explore all 14 examples, and draw walls of any shape in a wind tunnel, at the Coarse or Medium resolution. Projects, files, and the help are free too. Sketch CFD Pro adds:

  • inlets, outlets, fans, filters, heaters, gas sources, and probes, in any size;
  • gases and liquids, heat and buoyancy, and particles;
  • Fine meshes;
  • editing the examples;
  • importing your own paper drawings from a photo;
  • reports.

How much does Sketch CFD Pro cost?

In the United States, US$6.99 per month with a 7-day free trial, or US$49.99 per year with a 14-day free trial. Prices differ in other countries, and the free trial is for eligible accounts only. The app shows the price for your country before you confirm.

How do I turn on Sketch CFD Pro on another iPhone or iPad?

Sign in with the same Apple Account, open Menu > Sketch CFD Pro, and tap Restore purchases. Restore purchases is also in Menu > About Sketch CFD.

How do I cancel?

Open Settings > your name > Subscriptions > Sketch CFD Pro, and cancel. Subscribers can also use Manage subscription in Menu > About Sketch CFD. To avoid the next charge, cancel at least 24 hours before the free trial or the current period ends. Deleting the app does not cancel the subscription.

How do I get a refund?

Apple handles all payments, so refunds are requested from Apple at https://reportaproblem.apple.com. We cannot issue refunds.

What happens when my subscription ends?

Nothing you made is deleted. All your sketches and projects still open and run. Changing a design beyond the free features needs Sketch CFD Pro again.

The app says the subscription could not be checked.

Connect to the internet and try again. Sketch CFD Pro stays active without a connection, and a failed check never turns it off.

Where are my projects stored, and how do I move them to another device?

Projects are saved on your device and are included in iCloud or computer backups of the device. They are not shown in the Files app, and deleting the app deletes them. To keep a copy or move a project, use Menu > Projects and files > Save as a file. It saves a .sketchcfd.json file to Files, Mail, AirDrop, or another place you choose. On the other device, open that file with Sketch CFD from Files or Mail, or use Menu > Open a .json file.

How do I delete my data?

Delete sketches and projects in Menu > Projects and files, or delete the app to remove everything stored in it. To delete the purchase record that our subscription service keeps, email us the purchase ID from Menu > About Sketch CFD. The Privacy Policy explains the details.

Does Sketch CFD work offline?

Yes. Drawing, the calculation, and the paper import run on your device and work without a connection. Buying and restoring a subscription need a connection.

How do I import a sketch drawn on paper?

Open Menu > Import a drawing on paper. Try the sample drawing first; it is free. Importing your own photo is part of Sketch CFD Pro. For a good result:

  • Draw on plain white paper with the symbols on the notation card shown in the import screen.
  • Write the size of one grid square at the top of the sheet, or draw one dimension; this sets the scale.
  • Put one drawing on each sheet.
  • Photograph the whole sheet from above, in even light, on a surface darker than the paper.
  • On the review screen, check every part, role, and value against your drawing before you tap Use this.

The photo is read on your device and is not uploaded.

Why are the labels from my drawing empty on the review screen?

This version reads lines, symbols, and the circled unit, but not handwriting. The review screen shows each label with a field: type the value written on your drawing. Curves other than circles become straight segments.

Can I draw with Apple Pencil?

Yes. Once you use Apple Pencil, only Apple Pencil draws, and your fingers pan and zoom. To draw with a finger again, turn off Menu > Draw with Apple Pencil only.

How accurate are the results?

Sketch CFD is for education and learning only. Its results are estimates from a simplified two-dimensional model, verified against published benchmark cases but not validated against measurements or tested in real-world scenarios. Do not use them for safety, medical, engineering, or compliance decisions. You use them at your own risk; to the extent the law allows, Journey On is not responsible for decisions based on them. The Sketch CFD Terms of Use list the model’s limits and the benchmark cases.

What does the app do with my information?

It has no account and no ads, and your sketches and photos stay on your device. The Privacy Policy explains the subscription check in full.