Here's a few tips you can use when creating a Vray exterior rendering :
- When using wood, metals or any material that using reflection, if used only as accent and the quantity isn't dominant, you don't need to give it any reflection
- Bump value for exterior scene should be bigger than you usually use in interior scene, because sunlight can sometimes washout your texture.
- Check the back of your glass object (the inside part) because sometime you just map the material from the outside and the material will be see-through, but when you render it, it will create shadow (which of course we won't want from a glass material)
- If you using only one light direction and value for the entire scene, you can save you Irradiance Map Value and Light Cache Value to a specific file and then change the mode from Single Frame mode to From file mode. This way you can save a lot of rendering time.
- For exterior scene, you can add texture for your reflective material, such as glass or metal that is dominant in your scene. It will make it more realistic. But the texture should be in the same theme with your background
Have a nice day!