V-Ray Profiler

This page provides information about the V-Ray Profiler tool.

Overview

The V-Ray Profiler tool helps determine what parts of the scene are taking the longest time to render, compare the performance of different material settings and figure out the best settings for your scene. It does that by tracking the time spent in sampling shaders (materials and textures) and volumes during rendering and breaking down the different types of calculations done for each shader, such as GI, Reflections, Refractions, etc. It writes a JSON formatted report and an HTML report. Both can be read by a browser tracking software, the .json file can also be opened in a text editor offline.

The V-Ray Profiler report breaks down the tracked time into a few categories: Initialization, GI, Reflection, Refraction, and Others. These categories are only tracked if they were used by the shader. For example, a VRayMtl with no refraction enabled does not report anything for Refraction. The same happens if a shader with no Reflection layer is used.

For volumes, the V-Ray Profiler reports the time spent calculating each volume in your scene.

See the introductory article in Chaos' blog for more information.

UI Path

||Rendering|| > Render Setup > Settings > System (advanced) > V-Ray Profiler

Settings

Profiler – Enables the V-Ray Profiler. It generates profile reports on process duration. This report can be used to diagnose and optimize performance.

Mode – Determines the mode in which the V-Ray Profiler works.

All - Provides an in-depth report that includes both the system and rendering processes. For example, it shows detailed information per shader, like time spent calculating a shader's reflection, what shaders are reflected in it, and how long it took to sample them. This mode is suitable for scenes that include views through glass windows or in a mirror reflection. It can slow down the render by up to 30%.
System - Reports the time spent on system processes such as compiling geometries, building the Light Cache, etc.

Max depth – Determines the amount of bounces the rays make after coming into contact with an object. Keep in mind that this option depends on the materials' Reflection and Refraction Max depth parameters. If the GI is set to Brute Force, its Depth parameter influences the value of the V-Ray V-Ray Profiler's Max depth. This is reflected in the resulting profile. The Max depth value can go up to 8, however this is not recommended as it significantly slows down the render.

Output directory – Specifies the location of the V-Ray Profiler report files.

Open profile folder – Opens the specified directory.

Workflow

1. Turn on the V-Ray V-Ray Profiler by the checkbox
2. Change settings according to preference - Mode, Max depth and Path.
3. Render your scene3. Once you finish the render, you are able to find the .html and .json files in your designated directory. Rendering a second or third time generates more reports. Up to 3 reports can be generated in the same folder. Generating more, without changing the Output directory, causes the oldest report to be replaced by the new one. Tip: if you forget where you set the output files to be, the location is recorded in the log file.
4. Open the generated report2 :

• If you want to open the .json file:

Go to a third-party tracking software. Drag and drop your .json report into your browser and explore. The report shows the duration it took to render each element in nanoseconds. Alternatively, you can open the .json file in any text editing software on your machine.

• If you want to open the .html file:

Double-click on the file and it opens the report in the default browser. Most browsers are suitable for this. Explore the report. The report shows the duration it took to render each element in nanoseconds.

5. You can view the report's metadata either through the button in the browser report, or at the top of the .json file, when read through a text editor, under "product".

High bundle size example

Example of a result in All mode opened in a browser

Example of a result in System mode opened in a browser

Notes

1. If there are only layered materials in the scene (e.g., VRayBlendMtl) and the Max depth parameter of the V-Ray Profiler is set to 8, no more than 5 ray bounces are displayed in the profile. Make sure to lower the Max depth to get an accurate reading in such a scene.
2. When reading a V-Ray Profiler report in a browser, keep in mind that only up to 16 simultaneous events can be displayed. Simultaneous events are stacked on top of each other when displayed this way, and only up to 16 can fit at the same time, even though V-Ray can render more.
3. If you render a scene with Bitmaps multiple times, the V-Ray Profiler does not read them after the first render. To profile the Bitmaps after the initial render, you need to go to Render Setup > Settings > Tiled textures options and enable Clear cache on the render end.