Why is not Monster model displayed by glTFLoader of three.js on iOS?

Question

-Spec-

three.js version : r84 (NOW)

Device : iPad Air2

iOS version : 10.0.2

Browser : Chrome, Safari

-glTFLoader-

URL : https://threejs.org/examples/#webgl_loader_gltf

Monster -> NOT displayed

The others -> displayed

Why do I ask this question?

I have same issue in my self-made model. My model is exported by the following process.

My model is displayed on Windows and macOS, but not displayed on iOS. So, I'm in the same situation as the example.

Is there a rule for displaying it?

PS

I don't have new Android device. I don't check on Android...

Does it work for you in the gltf-test setup at https://cx20.github.io/gltf-test/examples/threejs/index.html?model=Monster&scale=0.05 ? — Marco13, Feb 09 '17 at 01:50
Hi Marco13. No, it doesn't work. I can see only gray background and XYZ axis on iPad Air2. — Evan.Titer, Feb 09 '17 at 08:14
Trying the monster with other libraries (on the same OS/browser), using the tests at https://github.com/cx20/gltf-test , might help to figure out whether the problem is specific for three.js. If so, it might be worthwhile to open it as an issue on the three.js GitHub page. (My first guess would have been that there is a problem with three.js and animations, but you said that the other models (particularly, the Cesium man?!) are working, so this is unlikely. I can't imagine what should be *so specific* about the monster, though...) — Marco13, Feb 09 '17 at 13:55

score 2 · Accepted Answer · answered Feb 10 '17 at 05:59

The cause is max number of bones.

If we use number of bones more than that are supported by OS, WebGL renderer outputs "too many uniforms" error.

I hear that iOS (10.x?) support 22 bones (Phong shading) or 22 bones (Lambert shading).

This issue has already been listed on github.

A simple solution is that we use less than 22 bones.

Hmm... It's a small number for human model and so on.

Thank you Marco13 and everyone.

note:

The Monster model has 32 bones. (my self-made model has 52 bones (!).)

I was able to learn how to debug with iOS safari + macOS safari.

The following is the log of the Monster model.

1 Answers1