V-Ray versions lower than 3.1 should be used with caution; in the materials within the BRDF section, there is Microfacet GTR (GGX). If your version is older than 3.1, the BRDF field will be empty. Choose Blinn, Phong, or Ward—whichever suits you best.

For Corona Render, it is recommended to install a version of at least 1.5, as the glossiness of materials is configured with PBR in mind.