Instanced Scenery Object Export Type is severly lacking in validations

[tngreene]

Upon close inspection it appears that multiple versions of the Instanced Scenery Object Export idea are being broken

• Animations are allowed
• Material ATTRs of different classes allowed, when normally they're only allowed if solid
• Material ATTRs of certain classes are allowed anyway
• Probably more.

We do some self consistent error checking validating ourselves and comparing reference materials in xplane_material_utils.py (see compareInstanced and validateInstanced)

Very few unit tests cover this feature.

These cover if instance materials with certain properties pass

• instanced.test.blend
• IST_2Mats_SameSPEC_DifSURF.test.blend
• IST_2mats_wDraping.test.blend

These cover if instance materials with certain properties fails (not the same spectacular)

• IST_2mats_VarSPEC.test.blend

More Reading

• Material Property Matrix
• Material and Instancing Model
• Material and Instancing Model

Developer Blog

• Third-Party Cars Should Really Be Instanced