When i want to use light in Vray 4.2, it inserts in the 3d scene as a new element. I’ve already designed the bulbs and would like to make them shine, so insert the light as a texture in a layer. it’s pretty much the same way as in Keyshot
I don’t know Keyshot. At V-Ray you can create an emissive material and assign it to any object, for example your light bulb.
(Emissive materials at high intensity can cause noise or fire flies. So, it could be useful to use additional lights. You could place a point light inside the bulb, but in this case you need to disable “cast shadows” at the emissive material (add the attribute “raytrace properties”).)