Is fSpy Free to Use?

Yes. fSpy is open source software and is totally free to download and use. The site also offers an optional donate button for anyone who wants to support the project, with the amount left entirely up to the user. Donations are accepted through PayPal.

What "Free" Covers

The download is available for Mac, Windows, and Linux, and there is no paid tier described on the site. The software is described as open source, cross platform, and built for still image camera matching.

If You Want to Support fSpy

Donating is presented as a choice rather than a requirement. The site's own framing is that you can pay whatever amount makes sense to you — including nothing, since the software remains free either way. If you do decide to contribute, the donate button on the site routes through PayPal.

What fSpy Actually Does

fSpy is a still image camera matching tool. You use it to work out the camera parameters behind a photograph, then carry those parameters into a 3D application so a rendered camera lines up with the original image.

Two paths are documented on the site:

• Blender — an official fSpy importer add-on sets the Blender camera parameters and can optionally set the camera background image.
• Other applications — without a dedicated importer, you copy the fSpy parameter values one by one into the target application.

Getting Parameters Into Apps Without a Dedicated Importer

The site outlines this process:

1. Set the camera viewport to match the dimensions of the input image.
2. Use the input image as the camera background.
3. Set the camera field of view.
4. Set the camera position.
5. Set the camera orientation.
6. Set the principal point, unless it coincides with the image midpoint.

Bottom Line

There is no cost barrier to using fSpy, and no account or payment is needed to download it. Donating is purely optional and handled through PayPal if you choose to do it.