[Build Actor] Duplicate materials appear invisible

[Grateful-Forest]

Acknowledgements

• I have searched for duplicate or closed bug reports
• I understand that I am supposed to provide my own legitimately obtained copy of the game

Describe the Bug

A known bug which is if you have multiple objects in a Blender file (primitives) for a custom model, and two objects have the same material applied to them, only the first object with the material displays, and any additional ones appear invisible in game (collision still works).

Interestingly, if multiple objects have no material (and get the black and white checker pattern in OpenGOAL), only the first object with the checker pattern gets the checker pattern (and others appear invisible).

It has legitimate uses, as sometimes you don't want to create a separate collision mesh and visual mesh. Sometimes you just want to use the same shape as both the collision and the visuals. This means you split up a single mesh if it needs more than one primitive, but, any secondary ones appear invisible, if they have the same material.

There is a workaround, which is to automatically duplicate materials:
for o in bpy.context.selected_objects:
o.data.materials[0]=o.data.materials[0].copy()

However, in practice, this often leaves Blender flooded with Wood.001, Wood.002, ... Wood.155 etc.

How To Reproduce

Create a cube in Blender.
Create a Material on it. Make it visible and collision.
Select half of it and separate it into a second Object.
Export as GLB file to Custom Models.
Create an actor with two mesh primitives.
View it in game to see the second primitive is invisible.

Does this problem occur on original hardware or PCSX2?

Yes, it's unique to OpenGOAL

Expected Behavior

Different objects referencing the same material should appear visually in game.

Environment Information

Using Blender 4.0.

Game Version

NTSC 1.0 (black label)

Have you set the game to something other than 60fps?

No