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You take pictures above, below, to the right, front, back, and even the naughtier areas because this thing has too many dimensions for a single image!
Well, you need to get with the times. Facebook has supported 3D posts since October 2017, and only nine months ago, they improved it to take PBR shading and image-based lighting and even this mind-bendingly awesome background feature:
It's not even hard. Well, as long as you have Substance Painter. But I'm sure we can make it work regardless.
See, when you export from Painter, there's a little secret export preset hidden near the top of the list called "glTF PBR Metal Roughness" That will give you a bunch of texture files—most of which will look like an acid trip because of compression, but the only file we're interested in is the .glb file. That's the file you drag into your next post, and you're done.
But what are the limitations?
I'm so glad you asked.
Since Facebook only made about 40 billion dollars last year, they still can't handle very big files. The limit's only 3 MB, which means you can't upload a high-poly sculpt with a 4K texture. For the hand example, I had to downscale to 512 × 512 textures because I never bothered to retopologize. How did I know the problem was the file size? I'll tell you that it was not the ridiculously general error message.
"3D Model Not Posted | Your 3D model could not be posted as it contains features we don't support, is of a file type we don't support, or contains errors."
GLB File Invalid
3D Model Not Posted | Your 3D model could not be posted as it contains features we don't support, is of a file type we don't support, or contains errors.
No, there's a helpful tool (by Facebook) that tells you what's wrong with your model so you can find out what to change.
I still haven't found any channels that won't work. Emissive, opacity, ambient occlusion will all display. Although the Facebook viewport will not tessellate and displace with your height map.
For the full list of requirements, read Facebook's own article.
But what if I don't have Substance Painter?
As it so happens, glb is not an entirely uncommon format. A lot of programs will have export options for it, and you can find converters online. There's even an official tutorial for this on the Facebook developer site. Honestly, everything I've written is from that site. You really should be going directly to the source.