I made a diamond material for my mesh diamond. How can i bake the material as a texture for the diamond, so i can it export for a game
Diamonds are heavily influenced by the environment they are in. The colors around them and mostly the way the light strikes them. You need to know if the diamond will be seen up close and personal with how the light shimmers and gleams through it, or will it be viewed only from a distance? That will effect how much you set up for it. How will it be used in the game too? Will it be seen once and only for a few seconds? Will it only be seen from one direction? Will there me movement around it? Do you want the lighting where it is to flicker or be steady? That effects if you will need to bake more then a diffuse map of the diamond.
Either way the first step is to select the edges to make as seams then to unwrap it. Then you will want to create the image that will be the map you are making. I cycles you will have to go to the shader editor and ad an image texture node with the image that will be your map. Only then can you go to the render tool shelf and set up the bake for the type of map you want to make. Once that is set up you click bake. If you are only baking the diffuse you will get one result, if you are baking everything at once you will get another. I would recommend baking it in a scene that is a near as possible as what it will be in in the game, especially if it will be seen up close and personal. It won't matter if only baking the diffuse, but as diamonds are transparent and sparkly, you are going to want to bake it different.