[Edwin C]

Why can I not open a material that was saved in the Maxwell 5 material editor in the Maxwell 4 material editor ?
"Why you ask just use Max 5" Well there is a even bigger problem We have a lot of older models that were created in Rhino 5 /Maxwell 4 and we can not open them in Rhino 6 /Maxwell 5 with the materials intacted. We do not want to spend hours and hours reapplying materials to our old models we just render in Rhino 5 /Maxwell 4
BUT if with our newer models we create in Rhino 6 /Maxwell 5 and happen to edit a material we now can not use that material in the our older models .
Is there a solution to this issue?

[luis.hijarrubia]

Well, it's not a bug, the material version has changed and is only forward compatible, not backwards. For example maxwell 5 materials have the emitter group field, and that new fields make it uncompatible with older versions.

In this kind of scenario maybe the best way to go is use referenced materials. So if you need to change something on a material or create new ones you use maxwell 4. To setup and render you use maxwell 5, but as the materials are referenced they are not overriten by maxwell 5, and they continue to be old version ones.