Optimization increase the size of the file

Hello. I was trying to optimize a model using “Reality Composer”, “Medium” optimization is now my model is heavier than before.

File Name:

Rapid Compact Core Version:

20.10.2021 12:48

Original size:
1.70 MB

Optimized size .glb :
2.83 MB

What I am doing wrong?

Thanks in advance


Hi Eduardo,

This is due to a flat texture resolution in that preset (medium = 2k textures). Your input only has 1k textures, that explains already most of the size gain. We will work on an update so you can edit these factory presets as well and change the desired resolutions.

Hope that already helped!


Excellent. BTW, Are there any other optimization that you would recommend me to try? I am using this models for Reality Composer.

Thanks in advance,


Hi Eduardo,

Another aspect is that the Reality Composer preset is not compressing the textures and will write png files, as the textures get compressed later on anyways (link)

For other optimizations, feel free to use a custom preset and set the output format in the las step to usdz (a glb is always written out for your convenience as well). In the custom preset you have full control over mesh resolution, as well as texture resolution and formats.

Overall your input model is already very optimized (less than 200 faces, 1 draw call, 1k textures). RapidCompact is best if you use it on non-optimized assets (for example a 3D scan) to get a similar result to the file you uploaded.

Hope that already helps!

Best Regards,