Here is the step by step guide that will helpful for you for setting up and rendering an interior scene using Choas Group Vray. The entire process has been broken down into sections, if you were to start from the beginning. The outline of this process is, how to how to remove unwanted splotches and how to adjust image samples to reduce noise.
Stage one – Turn on image sampling and indirect illumination (GI)
Adaptive DMC Sampler
Min subdivs = 1
Max Subdivs = 4
Clr thresh = 0.01
Irradiance map
Min rate = -3
Max rate = 0
HSph subdivs = 50
Interp. Samples = 20
Clr thresh = 0.3
Nrm thresh = 0.1
Dist thresh = 01
Light cache
Subdivs = 1000
DMC Sampler
Adaptive amount = 0.85
Noise threshold = 0.01
Min samples = 8
Global subdivs multiplier = 1
Render time = 0h 27m
Stage two – Reduce splotches
Adaptive DMC Sampler
Min subdivs = 1
Max Subdivs = 4
Clr thresh = 0.01
Irradiance map
Min rate = -5
Max rate = -2
HSph subdivs = 80
Interp. Samples = 20
Clr thresh = 0.3
Nrm thresh = 0.1
Dist thresh = 01
Light cache
Subdivs = 1000
DMC Sampler
Adaptive amount = 0.85
Noise threshold = 0.01
Min samples = 8
Global subdivs multiplier = 1
Notice that the splotches have almost cleared, but issues remain with the material reflections and shadow detail.
Render time = 0h 14m
Stage three – Increase the subdivisions
Adaptive DMC Sampler
Min subdivs = 1
Max Subdivs = 4
Clr thresh = 0.01
Irradiance map
Min rate = -5
Max rate = -2
HSph subdivs = 20
Interp. Samples = 20
Clr thresh = 0.3
Nrm thresh = 0.1
Dist thresh = 01
Light cache
Subdivs = 1000
DMC Sampler
Adaptive amount = 0.85
Noise threshold = 0.01
Min samples = 8
Global subdivs multiplier = 4
The materials and shadows are much cleaner now but there is still some evidence of noise and low detail within the reflections and shadows.
Render time = 0h 38m
Stage four – Increase secondary bounces
Adaptive DMC Sampler
Min subdivs = 1
Max Subdivs = 4
Clr thresh = 0.01
Irradiance map
Min rate = -5
Max rate = -2
HSph subdivs = 20
Interp. Samples = 20
Clr thresh = 0.3
Nrm thresh = 0.1
Dist thresh = 01
Light cache
Subdivs = 2500
DMC Sampler
Adaptive amount = 0.85
Noise threshold = 0.01
Min samples = 8
Global subdivs multiplier = 4
Render time = 0h 41m
Stage five – The final clean up
Adaptive DMC Sampler
Min subdivs = 1
Max Subdivs = 24
Clr thresh = 0.002
Irradiance map
Min rate = -5
Max rate = -2
HSph subdivs = 20
Interp. Samples = 20
Clr thresh = 0.3
Nrm thresh = 0.1
Dist thresh = 01
Light cache
Subdivs = 2500
DMC Sampler
Adaptive amount = 0.85
Noise threshold = 0.01
Min samples = 8
Global subdivs multiplier = 4
Render time = 1h 06m
The final result
Within your scene the settings may or may not need to be so high. Within the materials and shadows, the render is now clean and clear of any sampling issues. When setting up a scene to render, this guide outlines definitely helps you.