Regression: Blockbench Complex Models Fail to Load in 25w45a+ (Worked in 25w44a)

Regression Description

Complex 3D models created with Blockbench that loaded correctly in snapshot 25w44a now fail to load in snapshots 25w45a and 25w46a. Affected models show missing texture (purple-black) instead of the intended model.

Affected Versions

• Broken: 25w45a, 25w46a

• Working: 25w44a and earlier

Steps to Reproduce

1. Create a complex model in Blockbench (with multiple elements, textures, etc.)

2. Export as JSON and add to a resource pack

3. Test in 25w44a - model loads correctly

4. Test in 25w45a/25w46a - model fails to load

Evidence of Regression

This is a clear regression because:

• Same model files work in 25w44a

• Same model files fail in 25w45a+

• No changes were made to the model files between tests

Technical Details(Based only on my thoughts)

Affected models typically have:

• Multiple grouped elements

• Complex UV mapping

• Custom textures

• Animation data (in some cases)

Simple cube-based models still work, but more complex Blockbench exports fail.

Attachments

I've included:

1. A minimal resource pack with a complex Blockbench model

2. The original Blockbench project file (.bbmodel)

3. Screenshots comparing 25w44a (working) vs 25w46a (broken)