To run a Transient Cool analysis, you will need to model a mold. You can use the Mold Surface Wizard to create a mold around the part, feed system and cooling channels that you have modelled. Creating a mold surface is the first of three steps in creating a mold. After you create the mold surface, the next step is to create a triangular surface mesh. The final step is to create the 3D mold mesh.