V-Ray DMC Calculator

A tool to demonstrate the connection between
V-Ray's Image Sampler and DMC Sampler


- July 2014


v1.0 - March 03 2013 - Public Release.

v1.1 - March 25 2013 - Fixed the 'Adaptive Min Samples' formula to include clipping from the 'Max Secondary Samples' value.

v2.0 - May 22 2013 - Calculator redesign and added Notes section.

v2.1 - June 02 2013 - Fixed the 'Global Subidivs Multipler' formula to multiply the 'Subdivisions' value after being squared.

v2.2 - November 08 2013 - Added the 'Min Shading Rate' value from V-Ray 3.X to the calculator.

v2.3 - November 19 2013 - Fixed the 'Min Shading Rate' formula to no longer affect MIN Secondary Samples (Per Primary Sample) value.

v2.4 - January 30 2014 - Added the 'Divide Shading Subdivs' checkbox from V-Ray 3.X to the calculator.

v2.5 - July 06 2014 - Image Sampler MIN Subdivisions can no longer be accidentally set higher than Image Sampler MAX Subdivisions. General interface and terminology cleanup.

V-Ray Settings

Image Sampler (AA)

A. MAX Subdivisions

B. MIN Subdivisions

C. Min Shading Rate (leave at 1 if using V-Ray 2.X)

Divide Shading Subdivs (leave checked if using V-Ray 2.X)

DMC Sampler

D. Adaptive Amount

E. Global Subdivs Multiplier

F. Min Samples

Local Subdivisions (From a Light / GI / Material / etc)

G. Subdivisions

Image Samples (AA)

Per Pixel:


0 Max

Formula: A2

Currently: A2


0 Min

Formula: B2

Currently: B2

DMC Samples (Per Light / GI / Material / etc)

Per Image Sample:


0 Max

Formula: G2 * E / H

Currently: G2 * E / H

Raised by Min Shading Rate (C)


0 Min

Formula: J * (1 - D)

Currently: J * (1 - D)

Lowered by Max DMC Samples (J)

Raised by Min Samples (F)

Per Pixel:

0 Max

Formula: H * J

Currently: H * J

0 Min

Formula: I * K

Currently: I * K


This calculator serves to demonstrate the connection between V-Ray's Image Sampler and DMC Sampler, but can also be used to help optimize your V-Ray scenes. Simply input your V-Ray settings and the calculator will show you the resulting Max / Min Image and DMC samples per Image Sample and per Pixel. It will also show the formulas V-Ray uses to arrive at those values.

As of V-Ray 3.1 (3ds Max) this calculator is now implemented directly into the user interface of V-Ray to provide realtime feedback according to your scene's current settings. More info can be found here.

For an in-depth explanation of the inner workings of V-Ray and how the Image Sampler is connected to the DMC Sampler, I highly recommend reading my V-Ray Render Optimization tutorial, and Toni Bratincevic's Demystifying V-Ray DMC Sampler tutorial.