Compressing a normal map?

Hi there,

It advisable to avoid compressing normal maps using a tool such as Optimizilla?


It’s all comes down to how high quality you need your normal maps to be.

I’ve not used optomizilla, but I have used jpgs as normal maps… though many people here will say that you should only use lossless compression (i.e pngs) for normal maps.

What I don’t know is why , amongst others, insist on using tifs for normal maps when pngs exist and are smaller. Maybe an expert on image compression can explain why lossless compression is not as good as uncompressed.

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I would think any lossless compression would always preserve the bits just as well as an uncompressed format. TIFF is kind of the original “container” image format from 30 years ago with support for several different image and compression types (you can put lossy JPEG images inside a TIFF file, and a TIFF file may internally use lossless compression so TIFF does not always equal uncompressed).

Normal maps are not images no matter how pretty they look when viewed as such. They’re raw data that just happens to be conveniently stuffed into the color channels of an image format file, so I would never use a lossy compression format no matter how clever it is (since that cleverness will be centered around human perception which isn’t going to be applicable to normal maps).

Optimizilla will definitely mess up your normal maps.


I never knew that about tiffs - thanks, @Zoot !

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