Reply To: Overriding Instanced Mesh Data

[Omar Domenech]

Martin explained it perfectly. I’ll try to explain it more lame, just in case. When you are in object mode, it’s like your mesh object is a box, and when you go into edit mode it’s like opening the box to have access to its contents. Of course in this analogy the contents of the box are vertices, edges and faces. But also in this analogy, the contents of the box define the shape of the box outside, if the contents inside (edit mode) are shaped like a square box, then the box shape outside will be squared, if the contents inside form a triangle, then the box outside will be triangle shaped. So when you are in object mode you’re basically seeing a container. 

Object mode = A Container

Edit mode = The Data inside the Container

A material can be assigned at the object level or at the data level. 

When two objects are linked, meaning they are sharing their data, there’s two objects but they have the same data inside, so it’s two objects, or two boxes or two containers, but one data being used, and by definition those objects will have the same shape, because their data inside is the same… so them being linked, if your material is set to be on the data, then those two objects will share the same material also. Because it is at the data level of the mesh the material is being assigned to and there’s only one data, so they will have the same material. If you have 20 linked object and all of them the material is set to data, all the 20 objects will have the same material. If you change the material in one object, all the other objects will have their materials changed at the same time, because they are all sharing the same data, it’s 1 data and 20 objects. Material is at the data level, so they all change at the same time. Try it out for yourself and see. 

But if out of those 20 linked objects, in one of them you change the material from being set at the data and set it to object, then the material will be at the object level for that object, and remember, at the object level they are separate objects, so now that one can each have it’s own separate material, because at the object level they are separate objects nonetheless, with their own coordinate system, their one position, rotation and scale, it’s ONLY at the data level that they are one. 

Do the experiment, have a cube, have 5 linked duplicates of it, be sure the material is set to data, change the material in one and see the others change. Take one of those cubes and set the material to object, see now how the other 4 will share the same material and the one that you set to object you will be able to apply any material you like and the others wont change. Go into edit mode and see if you manipulate the vertices, all the 5 cubes will still change their shapes.