Compression with uv mapping?

[aaouviz]

Hi all,

I feel like I'm going crazy here, so I'm writing for help. Apologies for the long post.

First off; I'm quite new to threejs world (or any coding), so I'm currently on a steep learning curve.

I'm using gltfjsx on a glb file exported from 3dsmax. To be honest I'm not currently using the jsx file it creates but just loading the compressed glb file - which is excellent, by the way.

I tried for a very long time to find a workflow that allows me to export a model from 3dsmax to glb, then run the gltfjsx script to compress it. I then load this model, traverse it and apply threejs materials to objects depending on name. The hard part was compressing it whilst keeping texture uv mapping applied. I noticed this was often removed, depending on the settings used (correct me here if I'm wrong). I also noticed the texture.channel was changed (sometimes?),

I finally cracked it and got a 95% compression and managed to apply a material (with a jpeg texture) to the model with correct uv mapping. I was ecstatic.

The next day I tried the exact same workflow, same code, same model even and cannot - for the life of me - get the same result. I can apply the material fine if I use the uncompressed (model.glb) file, but if I try the same thing on the compressed (model-transformed.glb) it just does not work.

Usually I'd just figure I did something wrong to get the correct working result. But in this instance I'm 99% sure I did everything right and have just missed a key component which means it's no longer working.

My query; am I correct in understanding that texture uv mapping can be retained during compression? And if so, how do I ensure I can apply a textured material to this compressed glb.

Sorry for not providing any code; happy to do so, but I think I just need to learn a little more before I dig too deep.

Edit; I forgot to mention; I suspect something is amiss as when I try to do the compression again (and the texture mapping isn't working) on the same original glb the compressed file is 800kb smaller.