Faldo

Hi first time poster here So a friend wants to create a Boss mob for his Minecraft mod And he asked me to create the Mesh and texture because he doesn't havs the artistic skills for 3d modeling So now my question. What do i have to consider when creating the mesh and the textures for this custom mob? what kind of file should is use ? the mod is based on Minecraft version 1.7.10 and Forge 1614 What i mostly use is Blender 2.8.x