I am always running into the decision whether or not to make a mesh one connected mesh or to add small details as just separate parts to the model. Is there a best practices for this? Does it matter for games either way?
Fewer meshes equate to fewer draw calls, so generally you should try to go for as few as possible.
Split them when:
- one mesh would be so large that you'd need 32-bit index buffers to address (as this is generally too large)
- the sub-mesh uses different textures/shaders/materials
- the sub-mesh is somehow optional and might be detached or attached from the main mesh often (or similar reasons; basically you want to avoid having to update the main mesh's vertex buffer)