Adobe PDF 3D

I want to include 3D elements in my poster document. This should be possible using PDF’s 3D capability but it is proving very difficult. Adobe tell me they will only create 3D PDFs using U3D ECMA files without a third party plugin:

Adobe (2021) Adding 3D Models to PDFs (Acrobat Pro)
https://helpx.adobe.com/au/acrobat/using/adding-3d-models-pdfs-acrobat.html

And this is after paying for Acrobat Pro which is £25 a month PAYG. They say £15 but it’s misleading as that is for an annual plan.

I’ve started a free trial of Adobe Acrobat Pro and I’m shocked by how archaic and basic the interface is. Most people create PDFs using another app and export as PDF. Acrobat Pro is skewed towards issues of signing and countersigning documents rather than visual finesse.

I’ve never heard of U3D ECMA files and they don’t seem widely used. They’re the result of a collab between Bentley Systems, Intel, HP and Adobe in the early 2000s and the format is no longer maintained – this seems unhelpful.

Tetra 4D third party plugin will convert numerous 3D formats for use with PDF. They offer a free trial but would also cost money going forward to maintain.

Why can’t PDF use glTF like everybody else?

https://github.com/KhronosGroup/glTF