According to Defold 1.2.142 release notes materials should be able to work with more constants.
- DEF-3605 - Changed: Higher max number (16) of material constants for model/sprite/label.
But I get this message when I try to use more than 4 fragment constants in a material for a model:
ERROR:RENDER: Out of per object constant slots, max 4, when setting constant 'point3'