How can I compress my FBX file further below 5MB?

Question

I have an .fbx file that takes 58.8MB

After converting it to a .glb using draco compression with this package:

https://github.com/facebookincubator/FBX2glTF/tree/master/npm

The file now takes 28.4MB

Ideally, I would need to get the file below 5MB.

How can I achieve that ?

I am using 3DS Max.

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The character used to take the whole screen on load, now here is what I see after converting the .fbx to .glTF, reducing the size of the textures from 2048x2048 to 1024x1024 and converting them to .jpg :

Solution

To reduce the filesize of a model you’ll first need to know why it is the size it is. Often this is textures, mesh geometry, or animation data. If you export to .gltf instead of the binary .glb you should see textures in separate files, and geometry and animations (if any) in a .bin file.

To reduce the size of textures, you’ll want to use traditional image optimization tools and shouldn’t need to edit the glTF file at all.

To reduce mesh complexity, use a modeling tool (e.g. “Decimate” in Blender), or compress the glTF file using Draco (as you’ve done here). Reducing the size of animation is a more advanced topic.

Comments

[emackey]

I don't think a >90% compression ratio is realistic, even for the best compression algorithms, given 3D mesh input data. Your best bet may be to reduce the amount of incoming data, by removing fine-grained detail. Some packages call this "decimating" the mesh. It may also be possible to convert high-poly detail to baked normal maps on a low-poly mesh.

[TheProgrammer]

@emackey Ultimately, I would like to load the model inside three.js to let my users play with it. 5MB is already a lot for most internet connections. I agree that >90% compression is most likely unrealistic, I should have written something to the tune of "the smallest size possible". Do you think it would be possible to gzip a gltf file and unzip it on the client ? What size gains could I get from that in your opinion ?

[Don McCurdy]

It would be helpful to know what portion of your file size is geometry, and what portion is textures. Try exporting to .gltf instead of .glb to see those separately. Or if you can share the file, that's also helpful.

[emackey]

Sometimes a lot of the file size comes from textures. If you have PNG textures and can take a small quality reduction, convert them to JPG for smaller sizes.

[TheProgrammer]

@DonMcCurdy The .gltf is 91KB. All the rest of the 28.4MB is textures...

[Don McCurdy]

In that case you'll need to resize or further compress the images using the usual image compression tools. This can be done without editing the glTF file.

[TheProgrammer]

@DonMcCurdy I did that. Loaded the gltf file and now my character seems to have been scaled 1000 times smaller ? I don't understand what happened.

[TheProgrammer]

@DonMcCurdy Edited question with screenshot of current situation. No errors in console.

[TheProgrammer]

@DonMcCurdy Would you know how to scale it up ?

[Don McCurdy]

I assume this is three.js? See the three.js docs, you can scale things with object.scale.set( 1000, 1000, 1000 ) or similar.

[TheProgrammer]

@DonMcCurdy That's the thing. I can't. I tried doing gltf.asset.scale.set(1000,1000,1000), it tells mes scale is undefined.

[TheProgrammer]

@DonMcCurdy Regardless, this question has essentially been answered now (i.e.: convert to gltf and compress textures, etc...). Only remains for someone to formally do so. In the meantime, I opened a new question for the new issue: stackoverflow.com/questions/51785250/… with my code, hopefully it is a bit clearer that way

[TheProgrammer]

@DonMcCurdy So, could you please formally answer this question so I can accept your answer and then we can move to the other issue ? You were the one who suggested exporting to .gltf instead of .glb to see how much space the textures were taking.

[TheProgrammer]

I would welcome your input on this question if you have any: stackoverflow.com/questions/51773583/…